GREAT BASIN NATIVE PLANT PROJECT

2015 PROGRESSREPORT

USDA FOREST SERVICE, ROCKY MOUNTAIN RESEARCH STATION AND

USDI BUREAU OF LAND MANAGEMENT, BOISE, ID

APRIL 2016

COOPERATORS

USDA Forest Service, Rocky Mountain Research Station

Grassland, Shrubland and Desert Ecosystem Research Program, Boise, ID, Provo, UT, and Albuquerque, NM USDI Bureau 

of Land Management, Plant Conservation Program, Washington,DC

Boise State University, Boise, ID Brigham Young University, Provo, UT College of Western Idaho, Nampa, ID

Eastern Oregon Stewardship Services, Prineville, OR

Northern Arizona University, Flagstaff, AZ

Oregon State University, Bend, OR

Oregon State University Malheur Experiment Station, Ontario,OR

Private Contractors and Land Owners

Native Seed Industry

Texas Tech University, Lubbock, TX

University of California, Browns Valley, CA

University of Idaho, Moscow, ID

University of Nevada, Reno, NV

University of Nevada Cooperative Extension, Elko and Reno, NV Utah State University, Logan, UT

US Army Corps of Engineers, Junction City, OR

USDA Agricultural Research Service, Pollinating Insects Research Center, Logan, UT

USDA Agricultural Research Service, Eastern Oregon Agriculture Research Center, Burns,OR USDA Agricultural 

Research Service, Forage and Range Research Laboratory, Logan, UT USDA Agricultural Research Service, Great Basin 

Rangelands Research Unit, Reno,NV

USDA Agricultural Research Service, Western Regional Plant Introduction Center, Pullman,WA USDA Forest Service, 

National Seed Laboratory, Dry Branch, GA

USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR

USDA Natural Resources Conservation Service, Aberdeen Plant Materials Center, Aberdeen,ID USDI Bureau of Land 

Management, Morley Nelson Birds of Prey National Conservation Area, Boise,ID

USDI Bureau of Land Management, California, Idaho, Nevada, Oregon, and Washington State Offices

US Geological Survey Forest and Rangeland Ecosystem Science Center, Boise,ID

US Geological Survey Snake River Field Station, Boise,ID

US Geological Survey Western Ecological Research Center, Las Vegas, NV

Utah Division of Wildlife Resources, Great Basin Research Center, Ephraim,UT
ii

The Interagency Native Plant Materials Development Program outlined in the 2002 United States 

Department of Agriculture (USDA) and United States Department of Interior (USDI) Report to 

Congress encouraged use of native plant materials for rangeland rehabilitation and restoration where 

feasible. The Great Basin Native Plant Project is a cooperative project lead by the Bureau of Land 

Management (BLM) Plant Conservation Program and the United States Forest Service (USFS), Rocky 

Mountain Research Station that was initiated to provide information that will be useful to managers 

when making decisions about the selection of genetically appropriate materials and technologies for 

vegetation restoration. The Project is supported by the USDI Bureau of Land Management, Plant 

Conservation Program and administered by the USFS Rocky Mountain Research Station’s Grassland, 

Shrubland and Desert Ecosystem Research Program.

Research priorities are to:

 Increase the variety of native plant materials available for restoration in the Great Basin.

 Provide an understanding of species variability and potential response to climate change 

to improve seed transfer guidelines.

 Develop seeding technology and equipment for successful reestablishment of native

plant communities.

 Transfer research results to land managers, private sector seed growers, and restoration 

contractors.

We thank our many collaborators for their dedication and their institutions for their in-kind 

contributions. The wide array of expertise represented by this group has made it possible to address the 

many challenges involved with this endeavor. We especially thank Alexis Malcomb for the many hours 

she spent carefully editing and compiling this report and other outreach materials and Jessica Irwin for 

help in editing, as well as Corey Gucker for help in managing our financial reporting. Special thanks 

also to our resident technicians and volunteers: Nancy Shaw, Matt Fisk, Jameson Rigg, and Kristof 

Bihari for managing our field and laboratory research.

Francis Kilkenny 

USDA Forest Service

Rocky Mountain Research Station 

Boise, ID

ffkilkenny@fs.fed.us

Great Basin Native Plant Project

www.GreatBasinNPP.org

Citation

Kilkenny, Francis; Edwards, Fred; Malcomb, Alexis. 2016. Great Basin Native Plant Project: 2015 Progress 

Report. Boise, ID: U.S. Department of Agriculture, Rocky Mountain Research Station. 238 p.

GREAT BASIN NATIVE PLANT PROJECT

2015 PROGRESS REPORT
iii

GBNPP PROJECTS

Closing Projects 6

Continuing Projects 17

New Projects 11

PROJECT ACTIVITY

Presentations 38

Publications 30

Webinars 2

FY2015 Summary

NE

W 

PR

OJE

CTS
iv

Results in this report should be considered preliminary in nature and should not be quoted or cited 

without the written consent of the Principal Investigator for the study. The accuracy, reliability, and 

originality of work presented in this report are the responsibility of the individual authors. 

The use of trade or firm names in this report is for reader information only and does not imply 

endorsement by the USDA or USDI of any product or service.

Pesticide Precautionary Statement: This publication reports some research involving pesticide use. 

It does not contain recommendations for their use, nor does it imply that the uses discussed here 

have been registered. All uses of pesticides must be registered by appropriate State and/or Federal 

agencies before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or 

other wildlife― if they are not handled or applied appropriately. Use all pesticides selectively and 

carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide 

containers.

The USDA and USDI are equal opportunity providers and employers.
v

TABLE OF CONTENTS

I. GBNPP PROJECT OVERVIEW

COOPERATORS i

PROGRESS REPORT INTRODUCTION ii

FY2015 SUMMARY iii

DISCLAIMER iv

II. PROJECT HIGHLIGHTS

NEW PROJECTS 1

CONTINUING PROJECTS 6

III. GENETICS AND CLIMATE CHANGE

Testing the Efficacy of Seed Zones for Re-Established and Adaptation of Bluebunch Wheatgrass 

(Pseudoroegneria spicata)

Holly Prendeville, Francis Kilkenny, and Brad St. Clair 15

Conservation, Adaptation, and Seed Zones for Key Great Basin Species

Richard C. Johnson, Elizabeth Leger, Mike Cashman, and Ken Vance-Borland 22

Ecophysiological Analyses of Common Gardens to Inform Seed Transfer Guidelines

Matthew J. Germino, Martha Brabec, and Bryce Richardson 31

Species and Population-level Variation in Germination Strategies of Cold Desert Forbs

Elizabeth A. Leger and Sarah Barga 39

Dynamics of Cold Hardiness Accumulation and Loss in Sulphur-flower Buckwheat (Eriogonum 

umbellatum)

Anthony S. Davis, Matthew R. Fisk, and Kent G. Apostol 47

NEW PROJECTS

Morphological and Genetic Characterization of Blue Penstemon (Penstemon cyaneus)

Mikel Stevens and Robert Johnson 54
vi

A Field Test of Local Adaptation in Bluebunch Wheatgrass (Pseudoroegneria spicata)

Kathryn Alexander, Matt Orr, Ron Reuter, Francis Kilkenny, Brad St. Clair, and Holly Prendeville 58

Genetic and Environmental Regulation of Functional Traits: New Approaches for Restoration in 

Climate Change

Brad Butterfield and Troy Wood 63

Climate Change Effects on Native Plant Establishment and Annual Grass Invasion: Implications 

for Restoration

Beth Newingham and Keirith Snyder 67

Evaluation of Local Adaptation in Achnatherum hymenoides and Artemisia spp.: Implications for 

Restoration in a Changing Regional Climate

Lesley DeFalco, Daniel Shyrock, and Todd Esque 70

IV. PLANT MATERIALS AND CULTURAL PRACTICES

Smoke-Induced Germination of Great Basin Native Forbs

Robert Cox 78

Developing Protocols for Maximizing Establishment of Great Basin Legume Species

Douglas A. Johnson and B. Shaun Bushman 83

Bee Pollination and Breeding Biology Studies

James H. Cane 93

Native Forb Increase and Research at the Great Basin Research Center

Kevin Gunnell and Danny Summers 96

Plant Material Work at the Provo Shrub Sciences Lab

Scott Jensen 109

Aberdeen Plant Materials Center Report of Activities

Derek Tilley 112

Seed Production of Great Basin Native Forbs (7 Reports)

Clint C. Shock, Erik B. Feibert, Joel Felix, Nancy Shaw, and Francis Kilkenny

1. Irrigation Requirements for Native Buckwheat Seed Production in a Semi-Arid Environment 116

2. Irrigation Requirements for Seed Production of Five Lomatium Species in a Semi-Arid 

Environment 124

3. Irrigation Requirements for Seed Production of Five Native Penstemon Species in a Semi-Arid 

Environment 137

4. Prairie Clovers and Basalt Milkvetch Seed Production in Response to Irrigation 149

5. Native Beeplant (Cleome spp.) Seed Production in Response to Irrigation in a Semi-Arid 

Environment 155
vii

6. Irrigation Requirements for Seed Production of Various Native Wildflower Species Started in Fall of 

2012 160

7. Direct Surface Seeding Systems for the Establishment of Native Plants in 2015 168

NEW PROJECTS

Characterizing Germplasm Relationships and Maximizing Seedling Establishment of Utah Trefoil 

(Lotus utahensis Ottley)

B. Shaun Bushman and Douglas A. Johnson 177

V. SEED INCREASE

Coordination of Great Basin Native Plant Materials Development, Seed Increase, and Use

Berta Youtie 182

Seed Increase of Great Basin Native Forbs and Grasses for Restoration Research Projects

Clint C. Shock, Erik B. Feibert, Joel Felix, Nancy Shaw, Francis Kilkenny, Holly Prendeville, Brad St. Clair, 

and Anne Halford 186

VI. SPECIES INTERACTIONS

Drought Effects on the Symbiosis Between Wyoming Big Sagebrush Seedlings and Arbuscular 

Mycorrhizal Fungi

Marcelo D. Serpe and Bill E. Davidson 190

NEW PROJECTS

Comprehensive Assessment of Restoration Seedings to Improve Restoration Success

Kari Veblen and Thomas Monaco 197

Impacts of Climate Change and Exotic Species to Native Plant-Microbial Interactions

Kevin Grady, Paul Dijkstra, Catherine Gehring, Egbert Schwartz, and Hillary Cooper 199

VII. SCIENCE DELIVERY

Science Delivery for the Great Basin Native Plant Project

Corey Gucker 206

NEW PROJECTS

SeedZone Mapper Smartphone App Development

Andrew Bower and Charlie Schrader-Patton 207
viii

CRESTED WHEATGRASS DIVERSIFICATION

Presence of Native Vegetation in Crested Wheatgrass (Agropyron cristatum) Seedings and the 

Influence of Crested Wheatgrass on Native Vegetation

Krik Davies and Aleta Nafus 210

VIII. RESTORATION STRATEGIES

Herbicide Impacts on Forb Performance in Degraded Sagebrush Steppe Ecosystems

Marie-Anne De Graff and Aislinn Johns 218

NEW PROJECTS

Restoring Sagebrush After Large Wildfires: An Evaluation of Different Restoration Methods 

Across a Large Elevation Gradient

Kirk Davies 229

Forb Islands: Possible Techniques to Improve Seedling Establishment for Diversifying SagebrushSteppe Communities 

Douglas Johnson and Thomas Monaco 231

IX. APPENDIX I

PLANT INDEX 235
1

 

GENETICS AND CLIMATE CHANGE

Morphological and Genetic Characterization of Blue Penstemon (Penstemon 

cyaneus)

Mikel Stevens and Robert Johnson 54

 Our overall objective is to characterize the morphological and genetic variation within

blue penstemon (Penstemon cyaneus Pennell). 

 We will develop a genetic “fingerprint” of each the blue penstemon accessions using 

recent “next-generation DNA sequencing” techniques. The genetic variation will be 

evaluated for specific genotypes correlating between geography and morphological 

traits that may have value in plant restoration. 

 In order to evaluate morphological variability of blue penstemon we plan to establish at 

least two common gardens to assess variation between collected accessions of this 

species. 

 Tissue samples were collected and stored for later DNA isolation during the 2015 

growing season, from broadly distributed sites ranging from near Boise, ID on the west, 

to just north of Challis, ID on the north, across to several areas near Cody and Dubois, 

WY on the east, and samples collected south of Twin Falls, ID on the south. 

 Seeds were also collected from one to over a hundred plants from 50 of the accessions 

in which we had collected leaf tissue earlier in the season.

 It is anticipated that this project will take approximately four years to complete as part 

of a graduate students dissertation. We will be initiating both the first steps of common 

gardens of at least 20 accessions and molecular fingerprinting of more than 50 

accessions of blue penstemon beginning January, 2016. 

A Field Test of Local Adaptation in Bluebunch Wheatgrass (Pseudoroegneria 

spicata)

Kathryn Alexander, Matt Orr, Ron Reuter, Francis Kilkenny, Brad St. Clair, and Holly 

Prendeville 58

 Objectives of this project are to quantify early development and above ground traits 

(leaf shape, biomass, root to shoot ratio, and stomatal density) across seed zones 1, 3a, 

4, & 7b for bluebunch wheatgrass. Variation has been documented for mature plants, 

but information is limited on seed-to-seedling development. Since initial establishment 

often constitutes an obstacle to restoration success, it is important to analyze this stage 

of development. We expect to find significant differences in some or all of the traits 

listed above, and that these differences will be roughly grouped according to the seed 

zones from which each population was collected from.

2015 HIGHLIGHTS

NEW PROJECTS
HIGHLIGHTS ∙ NEW PROJECTS

2

 Quantify phenological variation within each of the eight seed zones. We expect to find 

variation in the timing of seed maturation sufficient enough to justify multiple harvest 

dates by commercial growers.

 Test for local adaptation to soil texture and water holding capacity. We expect that soil 

variation within a seed zone may be a significant driver of local adaptation for this 

species.

Genetic and Environmental Regulation of Functional Traits: New Approaches for 

Restoration in a Changing Climate

Brad Butterfield and Troy Wood 63

 Functional traits – organismal characteristics that mediate responses to and effects on 

the environment – are useful predictors of plant population establishment as well as the 

effects of those populations on the ecosystem services that are targeted in restoration 

activities.

 In order for functional traits to be useful predictors of restoration success, an 

understanding of the broad-sense heritability in those functional traits (i.e. how 

genetically entrained they are) and the environmental drivers of that heritability are 

necessary. We are taking a two-pronged approach to addressing this need.

 First, we are conducting a meta-analysis of functional trait broad-sense heritability, and 

its environmental dependence, from published literature on grasses.

 Second, we will measure broad-sense heritability of root functional traits in a common 

environment across a suite of grass species that are important for restoration across the 

western United States. Despite their importance in establishment, root traits are rarely 

measured, and the broad-sense heritability of those traits is completely absent from the 

literature on grasses. Thus, our proposed research will fill a critical need in 

understanding the diversity of available resources for restoration.

Climate Change Effects on Native Plant Establishment and Annual Grass 

Invasion: Implications for Restoration

Beth Newingham and Keirith Snyder 67

 This project investigates the effects of climate change (warming and/or drought) on 

invasive and native plant emergence, growth, and reproduction. In addition, we will 

investigate what native species mixtures may compete with invasive annual grasses in 

future climate.

 In field experiments, we will plant Bromus tectorum or Bromus rubens with and without 

various native grass and forb mixtures. 

 To date, we have explored various field sites but are still in the site selection process.

 Our results will provide information on: 1) the basic biology and competiveness of 

native and invasive plant species under future climate scenarios, and 2) the ability of 

Bromus rubens to expand its range in the Great Basin.

 Results will provide managers information on appropriate native species selection under 

future climate and their ability to compete with invasive annual grasses.
HIGHLIGHTS ∙ NEW PROJECTS

3

Evaluation of Local Adaptation in Achnatherum hymenoides and Artemisia spp.: 

Implications for Restoration in a Changing Regional Climate

Lesley DeFalco, Daniel Shyrock, and Todd Esque 70

 Global climate change is predicted to increase aridity across the southwestern United 

States, potentially shifting the distributions of plant taxa. Our project aims to evaluate 

the vulnerability of Great Basin restoration species to climate change by placing 

populations in common gardens located within the arid Mojave Desert. Transplanting 

Great Basin populations to warmer conditions will mimic future climate changes. 

 We developed a novel sampling design for Indian ricegrass (Achnatherum hymenoides), 

incorporating empirically-derived climate zones, climate change velocity predictions, 

and ecological distances to evaluate the degree to which Great Basin populations exhibit 

intraspecific variability in response to climate change and in restoration of arid sites. 

 We classified the southern Great Basin into six climate zones based on precipitation and 

temperature. We ranked climate zones according to their predicted velocity of climate 

change. Three zones showing both high climate change velocities and a gradient of 

decreasing ecological similarity to the Mojave Desert were selected for sampling. 

 Based on our approach, ricegrass populations will be sampled in 2016 and planted in 

up to five Mojave Desert common gardens. These experiments will develop 

management guidelines for selecting germplasm suitable for the restoration of arid sites 

in transition to warmer, drier conditions. 

PLANT MATERIALS AND CULTURAL PRACTICES

Characterizing Germplasm Relationships and Maximizing Seedling Establishment 

of Utah Trefoil (Lotus utahensis Ottley)

B. Shaun Bushman and Douglas A. Johnson 177

 Collections of Utah trefoil (Lotus Utahensis) were transplanted in two locations in 

Northern Utah and the first year’s data from the common garden plots was collected. 

The second year is underway. 

 Due to the high tannin content of other trefoil species, we are collaborating with Utah 

State University to measure tannin content in these collections.

 AFLP marker genotyping has been completed and analysis of relationships among 

collections is underway.

SPECIES INTERACTIONS

Comprehensive Assessment of Restoration Seedings to Improve Restoration 

Success

Kari Veblen and Thomas Monaco 197

 This project will assess the short-term establishment and long-term persistence of 

seeded shrub, grass, and forb species in the Great Basin, Colorado Plateau, and Rocky 

Mountain physiographic provinces.

 We will use >150 restoration sites that are monitored as part of the Utah Watershed 

Restoration Initiative (WRI) to: 1) investigate the roles of different pre-seeding 
HIGHLIGHTS ∙ NEW PROJECTS

4

restoration treatments, seeding approaches, environmental factors, and plant species 

traits on success of seeded species, and 2) quantify the cost effectiveness and efficiency 

of these seeding efforts.

 This effort will provide critical information to compare the biological- and costeffectiveness of different restoration treatments and seeding approaches. Our effort will 

also quantitatively assess the performance of species based on biological traits, which 

can be used to enhance plant material development and influence seeding success over 

both short and long-term periods.

Impacts of Climate Change and Exotic Species to Native Plant-Microbial 

Interactions

Kevin Grady, Paul Dijkstra, Catherine Gehring, Egbert Schwartz, and Hillary Cooper 199

 We propose to investigate the importance of maintaining community interactions for 

restoration using a common garden provenance approach. 

 This research will build upon current research in which we are investigating the 

effectiveness of adding live and commercial soil microbial inoculum during 

revegetation of Artemisia tridentata, Elymus elymoides, and Achnatherum hymenoides

with and without competition by Bromus tectorum at three common gardens (Mountain 

Home, Idaho; west Salt Lake, Nevada; Fredonia, Arizona). 

 This study will increase our knowledge of both abiotic and biotic adaptations and the 

importance of both to restoration.

 Collected all germplasm samples needed to run experiment.

 Planted and growing all germplasm samples at NAU greenhouse facility with 

preparation to transplant to common garden Spring/Summer of 2016.

SCIENCE DELIVERY

SeedZone Mapper Smartphone App Development

Andrew Bower and Charlie Schrader-Patton 207

 Development of prototype SeedZone mapper app for use in an on-line environment.

 Solicitation of proposals from app developers.

 Research and testing of multiple “off-the-shelf” apps for suitability. 

RESTORATION STRATEGIES

Restoring Sagebrush after Large Wildfires: An Evaluation of Different 

Restoration Methods Across a Large Elevation Gradient

Kirk Davies 229

 Evaluate five different methods to restore sagebrush after wildfires across a 3,000 ft. 

elevation gradient.

 Determine the effects of site characteristics on restoration treatment success and natural 

recovery. 
HIGHLIGHTS ∙ NEW PROJECTS

5

Forb Islands: Possible Techniques to Improve Forb Seedling Establishment for 

Diversifying Sagebrush-Steppe Communities

Douglas A. Johnson and Thomas Monaco 231

 Experimental designs were finalized for establishing two field study sites in Utah 

(Spanish Fork, Clarkston) and one in Idaho (Virginia). Each study site had three main 

site treatments (snow fence, N-sulate, control) laid out in a randomized complete block 

design with four replications. 

 The snow fence used was the unique patented Hollow Frame Fence System (HFFS) that 

allowed for the capture of snow in a uniform, densely packed drift between HFFS panels 

oriented perpendicular to the prevailing winds at each site. The N-sulate fabric treatment 

was a white fabric covering typically used to enhance seedling growth in small-seeded 

horticultural species. The third site treatment was a control treatment. 

 Plots at each study site were seeded on a PLS (pure live seed) basis during November 

2015. Thirty-three rows were seeded in each site treatment/replication combination with 

rows being 3-m (10 ft.) long and 61-cm (2 ft.) spacing between rows. Half of the row 

was a study that involved 16 various seed treatments for each of two Great Basin legume 

species: basalt milkvetch (Astragalus filipes) and western prairie clover (Dalea ornata). 

The other half of the row involved an evaluation of 10 diverse Great Basin forb species 

with three seed treatments for each species compared to two check species. 
6

 

 

GENETICS AND CLIMATE CHANGE

Testing the Efficacy of Seed Zones for Re-establishment and Adaptation of 

Bluebunch Wheatgrass (Pseudoroegneriaspicata)

Holly Prendeville, Francis Kilkenny and Brad St. Clair 15

 A reciprocal transplant experiment is being conducted in the Interior Northwest with 16 

common garden sites in two transects in regions with different environmental 

conditions. Each site was planted with 20 replicates from 39 populations plus two 

propagated lines of bluebunch wheatgrass (Pseudoroegneria spicata).

 First year survival was high with 80% of plants surviving through the 2015-growing 

season. Only one garden site failed shortly after planting due to extreme weather. A new 

site was planted in October 2015 to replace the site.

Conservation, Adaptation, and Seed Zones for Key Great Basin Species

Richard C. Johnson, Elizabeth Leger, Mike Cashman, and Ken Vance-Borland 22

 Seed zones for Sandberg bluegrass across the Inter-mountain West and the Great Basin 

have been mapped, published and posted at Seed Zone Mapper.

(http://www.fs.fed.us/wwetac/threat_map/SeedZones_Intro.html).

 Seed zones for Thurber’s needlegrass for the Great Basin have been completed and 

submitted for publication.

 Seed zones for Basin wildrye have been completed and submitted for publication. 

 Sulfur-flowered buckwheat evaluation data were collected from a common garden 

study of populations from the Intermountain West and Great Basin. 

Ecophysiological Analyses of Common Gardens to Inform Seed Transfer 

Guidelines

Matthew J. Germino, Martha Brabec, and Bryce Richardson 31

 A quantitative tool has been developed for assessing weather/climate effects on native 

perennial establishment in seeding or planting trials done for science or actual 

restoration. This tool allows learning about adaptation even when trials have little or no 

survival. 

 Physiological differences freezing and water-deficit thresholds are being identified for 

populations of sagebrush species and bluebunch wheatgrass (Pseudoroegneria spicata) 

in existing or new GBNPP common gardens.

 Common gardens arrayed across elevation gradients on the 2015 Soda Wildfire site are 

being established for big and low sagebrush species, local seeds from remnant/unburned 

plants inside the burn area, seeds collected by volunteer groups from around the 

2015 HIGHLIGHTS

CONTINUING PROJECTS
HIGHLIGHTS ∙ CONTINUING PROJECTS

7

perimeter of the burn area, and seed sources originating from surrounding regions 

procured by the BLM for aerial seeding.

Species and Population-Level Variation in Germination Strategies of Cold Desert 

Forbs

Elizabeth A. Leger and Sarah Barga 39

 We identified the dominant germination strategies of ten Great Basin annual and 

perennial herbaceous species.

 A majority of species had no preference for after-ripening temperature, but species 

exhibited differences in their preference for cold stratification.

 Five species were identified as facultative winter germinators by their ability to 

germinate at cold (2o C) temperatures, including: Agoseris grandiflora, Blepharipappus 

scaber, Collinsia parviflora, and Cryptantha pterocarya.

 We found that Agoseris grandiflora, Collinsia parviflora, Cryptantha pterocarya, and 

Microsteris gracilis were able to germinate under a wide range of conditions.

 In contrast, Gilia inconspicua, Mentzelia albicaulis, and Phacelia hastata possessed 

high levels of dormancy.

 Nine out of ten species displayed population level differences in germination strategies.

 Preliminary habitat maps were created for each species using herbarium data.

 The environmental variables that were most predictive were found to be unique to each 

species; though precipitation in summer, winter, and spring, a relative drought index, 

and winter maximum temperatures were important for multiple species.

 Accurate habitat maps can improve the efficiency of forb restoration efforts, increasing 

the likelihood that valuable seeds are planted into habitats where establishment is most 

likely to be successful.

Dynamics of Cold Hardiness Accumulation and Loss in Sulphur-flower

Buckwheat (Eriogonum umbellatum)

Anthony S. Davis, Matthew R. Fisk, and Kent G. Apostol 47

 Results indicate geographic, seasonal, and date*population interaction differences 

among accessions. Statistical significance was found between the two October 

collection periods and the wildland/common garden location. 

 Between the populations there was a low LT50 cold hardiness resistance level ranging 

from -10 to -16o C during the spring collection months and a high LT50 cold hardiness 

resistance level raining from -56 to -58o C in December. 

 December was the sample collection that appeared to be the most cold resistant, whereas 

April – August months tended to be similar in their lack of cold hardiness resistance.

PLANT MATERIALS AND CULTURALPRACTICES

Smoke-induced Germination of Great Basin Native Forbs

Robert Cox 78

 Extensive literature reviews for all focal species have been conducted and species have 

been prioritized by germination requirements and potential for smoke response.
HIGHLIGHTS ∙ CONTINUING PROJECTS

8

 19 species have been tested for smoke response in germination, with results being 

analyzed now.

Developing Protocols for Maximizing Establishment of Great Basin Legume 

Species

Douglas A. Johnson and B. Shaun Bushman 83

 A series of greenhouse studies were conducted to determine the effects of scarification, 

planting depth, and soil composition on germination and seedling emergence in western 

prairie clover (Dalea ornata), Searls’ prairie clover (Dalea searlsiae), and basalt milkvetch 

(Astragalus filipes). A planting depth of 19 mm (0.75 inches) retarded the rate of 

emergence for all species compared to a depth of 6 mm (0.25 inches), but only reduced 

total seedling emergence for basalt milkvetch. 

 With seed scarification in sandy soils, prairie clover seedling emergence exceeded 80%, 

while basalt milkvetch was less than 10%. With seed scarification in soils with higher 

clay content, total seedling emergence for prairie clover was reduced to 58-70%, while 

basalt milkvetch increased to about 30%.

 Laboratory studies showed that the combination of seed scarification, pre-chilling, and 

a sand substrate increased germination of basalt milkvetch to 35% compared to only 

10% for non-pre-chilled, unscarified seeds.

 Field studies at two sites in northern Utah showed that pre-chilled, scarified seed of 

basalt milkvetch established considerably better than unscarified or non-chilled seed. 

The pre-chilled, scarified seed treatments for basalt milkvetch could be scaled up to 

produce large quantities of germinable seed.

 Seed collections of Utah trefoil (Lotus utahensis) were made in southern Utah, Nevada, 

and Utah. These collections were evaluated for biomass production, phenology, 

flowering, seed production, tannin content, and forage quality at three common garden 

sites in northern Utah during 2014 and 2015. A DNA marker technique was used to 

evaluate genetic diversity among collections. Data are currently being analyzed from 

these studies. 

Bee Pollination and Breeding Biology Studies

James H. Cane 93

 Bees are necessary pollinators for seed production by silverleaf phacelia, Phacelia 

hastata.

 Silverleaf phacelia is self-compatible, with isolated individuals setting abundant seeds. 

Variable seed set among individuals masked any possible gain from outcrossing. 

 Silverleaf phacelia attracts the most abundant and richly diverse fauna of native bees of 

any of the 15 common native sage-steppe forbs systematically sampled for its wild bee 

guilds.

Native Forb Increase and Research at the Great Basin Research Center

Kevin Gunnell and Danny Summers 96

 Finalized data collection from the cushion buckwheat (Eriogonum ovalifolium) 

common garden study. Initial data analysis suggests that seed production may be too 

low in cushion buckwheat for commercial production, but could potentially be 
HIGHLIGHTS ∙ CONTINUING PROJECTS

9

increased with irrigation. Despite low seed production, the species does exhibit good 

drought tolerance in most accessions.

 Finalized data collection from the forb island, N-Sulate fabric study. Initial analysis 

suggests that the use of N-Sulate fabric in wildland settings has the potential to increase 

the initial emergence of native forb species, but the treatment has limited impact on the 

long-term persistence of most species tested in this study.

 Finalized data collection from the wildland forb seeding study. Initial analysis suggests 

that survival of seeded forb species can be improved in a Wyoming big sagebrush 

(Artemisia tridentata var. wyomingensis) community with the appropriate seeding 

methodology. However, selection of the best methodology is contingent on a number 

of factors including: species to be seeded, objectives in sagebrush reduction, and weedy 

species that may be released.

 Continued work to increase seed from wildland collections to support further research 

and increase distribution of native seed to commercial growers.

Plant Material Work at the Provo Shrub Sciences Lab

Scott Jensen 109

 26 wildland seed collections representing four species.

 Distributed 60 sources of seed to accommodate a variety of cooperative projects.

 Study installationfor the research project “Forb Islands: Possible Techniques to Improve 

Forb Seedling Establishment for Diversifying Sagebrush-Steppe Communities”.

Aberdeen Plant Materials Center Report ofActivities

Derek Tilley 112

 Release of Amethyst Germplasm Hoary Tansyaster.

 Progress towards release of Wyeth buckwheat.

 Development of 21 NRCS Plant Guides.

 Development of 7 Propagation Protocols.

 Modification to the Flail-Vac ® harvester for light airborne seed.

Seed Production of Great Basin Native Forbs (7 Part Report)

Clinton C. Shock, Erik B. Feibert, Joel Felix, Nancy Shaw, and Francis Kilkenny

1. Irrigation Requirements for Native Buckwheat Seed Production in a Semi-Arid 

Environment 116

 The seed yield of Eriogonum umbellatum and E. heracleoides were evaluated over 

multiple years in response to four biweekly irrigations applying either 0, 1 inch of 

water, or 2 inches of water (total of 0, 4 inches, or 8 inches/season). 

 Eriogonum umbellatum seed yield was maximized by 5 to 8 inches of water applied 

per season in warmer, drier years and no irrigation was needed in cooler, wetter years. 

 Averaged over ten years, seed yield of Eriogonum umbellatum was maximized by 6.5 

inches of water applied per season. 

 Over five seasons, seed yield of Eriogonum heracleoides was only responsive to 

irrigation in 2013, a dry year when seed yield was maximized by 4.9 inches of applied 

water.
HIGHLIGHTS ∙ CONTINUING PROJECTS

10

2. Irrigation Requirements for Seed Production of Five Lomatium Species in a Semi-Arid 

Environment 124

 The seed yield response to four biweekly irrigations applying either 0, 1 inch of water, 

or 2 inches of water (total of 0, 4 inches, or 8 inches/season) was evaluated for four 

Lomatium species over multiple years starting in 2007. 

 Over seven seed production seasons, Lomatium dissectum (fernleaf biscuitroot) seed 

yield was maximized by 5 to 6 inches of water applied per season in cooler, wetter 

years and by 8 inches of water applied per season in warmer, drier years. 

 Over nine seed production seasons, Lomatium grayi (Gray’s biscuitroot) seed yield 

was maximized by 0 to 5 inches of water applied per season in cooler, wetter years 

and by 5 to 8 inches of water applied per season in warmer, drier years. 

 Over nine seed production seasons, Lomatium triternatum (Nineleaf biscuitroot) seed 

yield was maximized by 4 to 8 inches of water applied per season in cooler, wetter 

years and by 8 inches of water applied per season in warmer, drier years. 

 Over four seed production seasons, Lomatium nudicaule (barestem biscuitroot) seed 

yield did not respond to irrigation. 

 In the two seed production seasons observed, seed yield of Lomatium suksdorfii

(Suksdorf’s desert parsley) responded to irrigation in 2015. 

3. Irrigation Requirements for Seed Production of Five Native Penstemon Species in a SemiArid Environment 137

 The seed yield response of five Penstemon species to four biweekly irrigations 

applying either 0, 1, or 2 inches of water (a total of 0, 4, or 8 inches of water/season) 

was evaluated over multiple years. 

 Penstemon acuminatus (sharpleaf penstemon), Penstemon speciosus (royal 

penstemon), and Penstemon cyaneus (blue pentstemon) seed yields were maximized 

by 4 to 8 inches of water applied per season in warmer, drier years and were not 

responsive to irrigation in cooler, wetter years. 

 Penstemon pachyphyllus (thickleaf beardtongue) seed yields were maximized by 8 

inches of water applied per season in warmer, drier years and were not responsive to 

irrigation in cooler, wetter years. 

 In 6 years of testing, seed yields of Penstemon deustus (scabland penstemon) only 

responded to irrigation in 2015, with 5.4 inches of water applied resulting in the 

highest yields.

4. Prairie Clover and Basalt Milkvetch Seed Production in Response to Irrigation 149

 The seed yield response of three native legume species to irrigation was evaluated 

starting in 2011. Four biweekly irrigations applying either 0, 1, or 2 inches of water 

(a total of 0, 4 inches, or 8 inches/season) were tested. 

 Over the five year period of study, Dalea searlsiae (Searl’s prairie clover) seed yield 

was maximized by 6 - 9 inches of water applied per season in warmer, drier years 

and by 0 inches of water applied per season in cooler, wetter years. 

 Dalea ornata (western prairie clover) seed yield was maximized by 4-8 inches of 

water applied per season in warmer, drier years and by 0 inches of water applied per 

season in cooler, wetter years. 

 Astragalus filipes (basalt milkvetch) seed yield was not responsive to irrigation. 
HIGHLIGHTS ∙ CONTINUING PROJECTS

11

5. Native Beeplant (Cleome spp.) Seed Production in Response to Irrigation in a Semi-Arid 

Environment 155

 The seed yield response of Cleome serrulata (Rocky Mountain beeplant) and Cleome 

lutea (yellow spiderflower or yellow beeplant) to four biweekly irrigations applying 

either 0, 1 inch of water, or 2 inches of water (total of 0, 4 inches, or 8 inches/season) 

was evaluated over multiple years. 

 Cleome serrulata seed yield was maximized by 8 inches of water applied per season 

in 2011, but did not respond to irrigation in 2012, 2014, or 2015. 

 Cleome lutea seed yield did not respond to irrigation in 2012, 2014, or 2015. 

 Cleome stands were lost to flea beetles in 2013.

6. Irrigation Requirements for Seed Production of Various Native Wildflower Species 

Started in the Fall of 2012 160

 By burying drip tapes at 12-inch depth and avoiding wetting the soil surface, 

experiments were designed to assure flowering and seed set without undue 

encouragement of weeds or opportunistic diseases. 

 The trials reported here tested the effects of three low rates of irrigation on the seed 

yield of 13 native wildflower species.

7. Direct Surface Seeding Systems for the Establishment of Native Plants in 2015 168

 In 2015, the seven planting systems were tested for emergence of 11 important 

species, most of which are problematic to establish.

 Planting systems including row cover have been the most consistent factor for 

improving stand establishment over the years of trials at the Malheur Experiment 

Station.

 Seed treatment, sawdust, and sand are factors that, for some species, in some years, 

have shown value in improving stand but their performance has not been consistent.

SEED INCREASE

Coordination of Great Basin Native Plant Project Plant Materials Development, 

Seed Increase, and Use

Berta Youtie 182

 Preparation and planting of bluebunch wheatgrass (Pseudoroegneria spicata) test sites

in recently burned areas within seed zones to test the efficacy of using species-specific 

provisional seed zones and seed transfer guidelines in native plant restoration efforts

after fires.

 Increase of native seed collections for the Great Basin Native Plant Project (GBNPP)

in Eastern Oregon and Northern Nevada.
HIGHLIGHTS ∙ CONTINUING PROJECTS

12

Seed Increase of Great Basin Native Forbs and Grasses for Restoration Research

Projects

Clint Shock, Erik Feibert, Joel Felix, Nancy Shaw, Francis Kilkenny, Holly Prendeville, Brad 

St. Clair, and Anne Halford 186

 Seed was to be increased of selected Great Basin native forbs and grasses for 

restoration research projects. 

 During the last year seed was increased for bluebunch wheatgrass (Pseudoroegneria 

spicata) and winterfat (Krascheninnikovia lanata).

SPECIES INTERACTIONS

Drought Effects on the Symbiosis Between Wyoming Big Sagebrush Seedlings 

and Arbuscular Mycorrhizal Fungi

Marcelo D. Serpe and Bill E. Davidson 190

 Artemisia tridentata spp. wyomingensis (Wyoming big sagebrush) seedlings were 

exposed to a gradual and terminal drought to investigate the effect of water stress on 

colonization by the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis. 

 Per unit root length, no differences in total and arbuscular colonization were detected 

between well-watered and water-stressed seedlings. This was observed after the waterstressed seedlings had fully closed their stomata, thus indicating that Wyoming big 

sagebrush seedlings did not exclude R. irregularis under drought. 

 The pattern of colonization observed combined with results from seedling survival 

suggest that the association between Wyoming big sagebrush and R. irregularis ranges 

from mutualistic under mild water stress to parasitic under severe water deficits. 

SCIENCE DELIVERY

Science Delivery for the Great Basin Native Plant Project

Corey Gucker 206

 Maintaining contact with Great Basin Native Plant Program (GBNPP) cooperators 

through regular correspondence, event alerts, and communication of project due dates.

 Updating and producing hard copy posters and brochures for Great Basin events and 

meetings.

 Regularly updating the GBNPP website with meeting announcements, new

publications, and updated cooperator information.

 Helping to develop the agenda and secure presenters for the annual GBNPP meeting.

 Tracking and reporting GBNPP accomplishments.

CRESTED WHEATGRASS DIVERSIFICATION

Presence of Native Vegetation in Crested Wheatgrass (Agropyron cristatum) 

Seedings and the Influence of Crested Wheatgrass on Native Vegetation

Kirk Davies and Aleta Nafus 210
HIGHLIGHTS ∙ CONTINUING PROJECTS

13

 We measured basal cover, density, species richness and diversity on 121 sites that 

spanned a 54230 km2(20.166 mi2) area in southeastern Oregon. 

 Plant community composition of crested wheatgrass (Agropyron cristatum) stands was 

quite variable. Some seedings were a monoculture of crested wheatgrass while others 

contained a more diverse assemblage of native species. 

 Environmental factors explained a range of functional group variability ranging from 

0% of annual grass density to 56% of large bunchgrass density. 

 Soil texture appeared to be the most important environmental characteristic explaining 

functional group cover and density 10-50 years post seeding and was included in the 

best regression models for all plant functional groups. 

 All native vegetation functional groups were positively correlated with soils lower in 

sand content. 

 Pre-seeding treatments/disturbance and precipitation in the year following seeding have 

long-term effects on plant community dynamics.

 Moderate grazing reduced crested wheatgrass monoculture characteristics relative to 

ungrazed sites.

RESTORATION STRATEGIES

Herbicide Impacts on Forb Performance in Degraded Sagebrush Steppe 

Ecosystems

Marie-Anne De Graff and Aislinn Johns 218

 Fuel load reduction treatments (i.e. mowing, herbicide applications, a combination of

mowing and herbicide applications, and grazing) had no impact on soil microbial 

activity and soil nitrogen availability.

 Imazapic applications significantly impacted performance of Astragalus filipes, 

Achillia millefolium, and Sphaeralcea grossularifolia, regardless of concentration and

timing of application, suggesting that imazapic is not specific to cheatgrass, and that 

the use of imazapic could negatively impact native forbs.

 Although imazapic negatively impacted Astragalus filipes, Achillia millefolium, and 

Sphaeralcea grossularifolia, the response of Astragalus filipes to imazapic 

applications was significantly less negative than that of the other species.
14

 GENETICS AND CLIMATE CHANGE 
GENETICS AND CLIMATE CHANGE

15

Project Title Testing the Efficacy of Seed Zones for Re-Establishment 

and Adaptation of Bluebunch Wheatgrass 

(Pseudoroegneria spicata)

Project Agreement No. 13-IA-11221632-161

Principal Investigators and Contact Information

Holly Prendeville, Research Geneticist

United States Forest Service

Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7300, Fax 541.750.7329

hollyrprendeville@fs.fed.us

Francis Kilkenny, Research Biologist

United States Forest Service

Rocky Mountain Research Station

322 E Front Street Suite 401

Boise, ID 83702

208.373.4376, Fax 208.373.4391

ffkilkenny@fs.fed.us

Brad St. Clair, Research Geneticist

United States Forest Service

Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7294, Fax 541.750.7329

bstclair@fs.fed.us

Project Description

Introduction

Land managers face numerous challenges when managing and restoring healthy ecosystems that 

are resilient to climate change. One challenge is determining and procuring the appropriate plant 

material to restore an area. In the western United States, plant species span a wide range of 

climates from arid desert to temperate rain forest to alpine areas. Climatic extremes can lead to 

natural selection on populations leading to improved survival and reproduction in local 

environments, i.e. local adaptation. Adaptation can occur on a regional level particularly along

climatic gradients. Thus, federal agencies have directives to use genetically appropriate materials 

that are locally adapted to ensure success in restoration activities and healthy ecosystems. To 

guide the movement of appropriate plant materials in restoration and reforestation, seed zones 

have been developed (Campbell and Sorensen 1978, Johnson et al. 2004). Seed zones separate 

areas by plant performance and/or climatic conditions important to plant growth, survival, and 
GENETICS AND CLIMATE CHANGE

16

reproduction. Provisional seed zones combine minimum winter temperature with aridity (mean 

annual temperature/mean annual precipitation) to delineate areas of similar climate (Bower et al. 

2014). Empirical seed zones are for a particular species and incorporate climatic data along with 

genetically differentiated traits important to survival and reproduction. Empirical seed zones 

have been developed for over 20 species in the western United States. 

Bluebunch wheatgrass (Pseudoroegneria spicata) is an ecologically important restoration 

species (Daubenmire 1942, Harris 1967) that occurs in a wide range of habitats in the western 

United States. Populations of bluebunch wheatgrass differ in several traits important for 

adaptation to precipitation and temperature (St. Clair et al. 2013). Seed zones for bluebunch 

wheatgrass demarcate areas with similar climate and populations with climate-associated genetic 

variation. To examine if populations are locally or regionally adapted requires comparing 

performance of local and non-local populations in a reciprocal manner (Kawecki and Ebert 

2004). We are using a reciprocal transplant experiment to investigate the efficacy of bluebunch 

wheatgrass seed zones. Results from this experiment will determine if seed zones for bluebunch 

wheatgrass are delineated appropriately or if they need modification. 

Objectives

 Evaluate adaptation of bluebunch wheatgrass (Pseudoroegneria spicata) populations 

from local seed zones relative to non-local seed zones.

 Model adaptation as a function of source location and common garden climates.

 Characterize traits and climatic factors important for adaptation.

 Model effects of climate change on native populations and consequences of assisted 

migration for responding to climate change.

Methods

Bluebunch wheatgrass is a C3, long-lived perennial bunchgrass native to the western United 

States. It exists in habitats that range in mean annual temperature (3-11° C), annual precipitation 

(21-187 cm), and elevation (230-2460 m). We investigate the effectiveness of empirical seed 

zones for bluebunch wheatgrass by comparing establishment, survival, and reproduction of 

populations from local seed zones to non-local seed zones. We hypothesize that in the long-term 

populations from local seed zones will better establish, survive, and reproduce. To test this 

hypothesis, we established a reciprocal transplant study at 16 sites located in two broad regions 

(i.e. transects) (Figure 1). The two broad regions include: (1) a transect through hot, dry climates 

of the lower Snake River Plain to cool, somewhat wet climates of the transverse ranges of the 

Great Basin to the cold, dry climates of the upper Snake River Plain, and (2) a transect from hot, 

dry climates of the Columbia Plateau to cool, wet climates of the Blue Mountains to the cold, dry 

climates east of the Blue Mountains. Within each transect, we reciprocally planted native 

populations from eight seed zones into eight sites that represent the climate of each seed zone 

(Figure 1). In addition, we planted two propagated lines at all sites. 

Seed was collected from 78 populations throughout the two broad regions in 2013. The 

University of Idaho was contracted to produce containerized planting stock for the study in 2014. 

Collaborators provided land for common garden sites. The 16 common gardens were identified, 

prepared and established in 2014. Several common gardens were fenced to protect plants from 

herbivory. Each common garden was planted with 39 populations and two propagated lines 

(Anatone and Goldar) for a total of 820 plants surrounded by two rows of buffer plants. A few 

common garden sites had an additional treatment included: (1) a seed zone from the other 
GENETICS AND CLIMATE CHANGE

17

transect, or (2) an extra propagated line (Wahluke) for a total of 1000 plants per common garden. 

The experimental design at each common garden is a split-plot design with populations planted 

by seed zone into subplots and all seed zones present within a plot. Each site includes four 

replicate plots. Each subplot has 25 plants: five replicates of five populations or all one 

propagated line. However, only four populations were available from the hottest, driest seed zone 

within each transect and had additional replicates to reach 25 plants per subplot. Spacing is 0.6 m 

x 0.8 m between plants.

Each site was visited in 2015 to record leaf length, width and roll, survival, reproductive 

phenology, herbivory, root crown diameter, and number of reproductive stalks. Reproductive 

stalks were collected from a subset of individuals per population at each site to estimate seed 

production. Sites will be revisited in 2016 and 2017. Weather data loggers were installed at plant 

height at each site to record local temperature for comparison with regional weather stations and 

climate interpolation models. Common gardens are managed to control weeds to ensure

establishment and to reduce the effect of competing vegetation to allow better evaluation of 

differences associated with local climates.

Expected Results and Discussion

Since there is genetic differentiation among populations of bluebunch wheatgrass (St. Clair et al. 

2013) and these populations exist in a wide range of environmental extremes, we expect that 

bluebunch wheatgrass is locally adapted. We focus on the regional level of adaptation (ref. 

regional adaptation) as restoration on this level is more logistically and financially feasible to 

procure, produce and disseminate native seeds. 

Across 16 common garden sites, survival through the 2015-growing season was high (>80%). 

However, the majority of plants at one common garden site did not survive a month after 

transplant due to an extreme weather event. Among the remaining sites, we found differences in 

traits (except leaf length) due to transect; which is likely due to different regional climatic 

patterns between transects. This variation between transects allows us to investigate how plants 

perform within a seed zone with natural environmental variation (i.e. deviations from average 

temperature and/or precipitation). Populations varied in survival and reproduction within many 

sites, which is evidence of genetic differentiation among populations for these traits. We 

observed plants from local seed zones with statistically different phenology and reproduction 

than plants from non-local seed zones. Bluebunch wheatgrass is a perennial plant that can live 

for decades; thus, it is challenging to interpret variation observed in reproductive phenology, leaf 

traits, size, and reproduction in year one among plants from different seed zones planted in 

various seed zones. For instance, high reproduction in year one may reduce future survival. Data 

collected in 2016 and 2017 will clarify the implications of results.

Management Applications and/or Seed Production Guidelines

Since bluebunch wheatgrass is an ecologically important restoration species (Daubenmire 1942,

Harris 1967), it is essential to have effective seed-transfer zones to improve restoration success. 

This study will examine the efficacy of seed zones for bluebunch wheatgrass to ensure successful 

establishment and allow for long-term adaptation by maintaining genetic diversity. The results of 

this study will help land managers to determine sources of bluebunch wheatgrass populations for 

post-fire restoration of an area. Furthermore, this study will explore the consequences of 

changing climates for adaptation by substituting space for time to evaluate various populations in 

different climates. Results from this portion of the study will aid land managers in maintaining 
GENETICS AND CLIMATE CHANGE

18

and restoring areas considering future climate changes. Long-term productivity and adaptation 

will be modeled to allow evaluation of trade-offs between different management options for 

current and future climates. Plant material movement guidelines and associated seed zones can 

be adjusted based on results from this study and management objectives.

Presentations

Conferences

Prendeville, H. R.; Kilkenny, F.; St. Clair, J. B. 2015. Reciprocal transplant study to test 

adaptation of bluebunch wheatgrass. Great Basin Consortium Conference; 2015 February 17-19; 

Boise, ID.

Prendeville, H. R.; St. Clair, J. B. 2015. Geographic variation in adaptation and population

movement guidelines in restoration species in the western United States. Ecological Society of 

America Annual Meeting; 2015 August 9-14; Baltimore, MD. Organized Oral Session; Native 

Plant Materials Development Research: Synthesis, Cutting Edge and Use Implications.

Abstract: Populations are often adapted to local environments. Restoration efforts on public 

lands in the Western U.S. have had mixed success for a number of reasons including the extreme 

climatic conditions. To yield successful outcomes in restoration efforts the use of native plant 

Per transect

8 sites 

34 pops

1 2a 3a 4 5 6a 6b 7a 7b

BLUEBUNCH WHEATGRASS SEED ZONES

Warmer/Dryer Climate (small plants) - > Wetter/Cooler Climate (larger plants)

Figure 1. Map of bluebunch wheatgrass (Pseudoroegneria spicata) populations 

(black circles) used in eight common gardens (stars) in each transect (delineated) 

in the northwest US.

Per Transect

8 sites

39 populations
GENETICS AND CLIMATE CHANGE

19

material from areas similar to the restoration site is essential. Thus, seed transfer zones have been 

developed to guide restoration efforts. A provisional seed zone map has been developed for 

species without species-specific seeds zones. This provisional map integrates climatic variables 

along with level III ecoregions and has been found to account for the majority of variation 

among populations of grass and forb species. For a handful of species, seed zone maps specific 

to the species have been developed, but have yet to be tested. Here we present a summary of seed 

transfer guidelines for restoration in the western United States. We then focus on our current 

investigation of the efficacy of seed zones for bluebunch wheatgrass (Pseudoroegneria spicata) 

to ensure successful establishment and allow for long-term adaptation by maintaining genetic 

diversity. We test the hypothesis that in the long-term populations from local seed zones will 

better establish, survive, and reproduce. To test this hypothesis, we established a reciprocal 

transplant study in two broad regions each with eight seed zones with each seed zone represented 

by four to five wild populations.

To increase the success of restoration, we suggest that land managers use provisional or species 

specific seed zones in conjunction with species-specific information and knowledge of microsite 

differences to guideline seed transfers/population movements. Results from previous works and 

this study support this suggestion and will improve success rates of restoration in the Western 

United States. Focusing on one species we examined the effectiveness of seed zones by 

comparing differences in establishment, survival, and reproduction of bluebunch wheatgrass 

from local seed zones compared to non-local seed zones planted in 16 common gardens. In the 

first year of this study, we found that overwinter survival was high among all source populations 

planted in different seed zones. This likely is due to above average temperatures and 

precipitation among sites. By substituting space for time to evaluate different populations in 

different climates, this study explores the consequences of changing climates for adaptation. 

Population movement guidelines and associated seed zones can be adjusted based on results 

from this study and management objectives.

St. Clair, J. B. 2015. The development and use of seed zones to ensure adapted plant materials 

for sustainable restoration. Society of Ecological Restoration 6th World Conference; 2015 August 

24-27; Manchester, United Kingdom.

Abstract: A seed zone is an area in which plant material collected from native stands can be 

transferred with little risk of being poorly adapted to the new location. Seed zones and 

population movement guidelines have a long history in forestry in the western United States to 

help ensure successful reforestation and productivity of forest stands. More recently seed zones 

have been developed for shrubs, grasses and forbs based on knowledge of geographic genetic 

variation in adaptive traits. Initially seed zones may be delineated using the best available 

knowledge of environmental factors driving adaptation. For example, provisional seed zones 

based on winter temperature and aridity have been developed in the United States for species 

which lack genetic information. But the specific environmental factors and the scale to which 

populations are adapted to their local climates may vary among species (generalists versus 

specialists). Empirical seed zones for specific species may be developed using short-term 

genecology studies in which population variation in adaptive traits as determined in common 

gardens is modeled as a function of the seed-source climates in which the populations evolved. 

Seed zones based on genecology studies, however, assume local adaption. Local adaptation is 

best tested using reciprocal transplant studies in which samples of genotypes from local 
GENETICS AND CLIMATE CHANGE

20

populations are compared with samples from distant populations in a series of common garden 

trials. Reciprocal transplant studies also provide the best information of the long-term 

consequences of maladaptation. Researchers in the western United States have used genecology 

studies to develop seed zones for many restoration species, and are testing the efficacy of those 

seed zones using reciprocal transplant studies. Resource managers in federal agencies in the 

western United States are now using both provisional and empirical seed zones to guide the 

collection, storage, increase, and deployment of native plant materials in restoration projects.

Webinars

Kilkenny, F. F. 2015. Seed zones and climate change. May 20, 2015. Available: 

https://youtu.be/c1944poBtr8

St. Clair, J. B.; Erikson, V.; Bower, A. 2015. The development and use of seed zones, use of seed 

zones in procurement and deployment of native plant materials, and provisional seed zones for 

native plants; 2015 January 29. Available: http://greatbasinfirescience.org/eventswebinars/2015/1/29/the-development-and-use-of-seed-zones-use-of-seed-zones-in-theprocurement-and-deployment-of-native-plant-materials-and-provisional-seed-zones-for-nativeplants?rq=seed%20zone

Publications

Kilkenny, F. F. 2015. Genecological approaches to the effects of climate change on plant 

populations. Natural Areas Journal 35: 500-512.

Additional Products

 Plant materials development for eight seed zones for bluebunch wheatgrass at Oregon 

State University Malheur Experimental Station.

 Field tour at Oregon State University Malheur Experimental Station on seed zones, native 

seed production, and bluebunch wheatgrass; May 14, 2015.

 Seed zone maps and map layers for bluebunch wheatgrass are available for download and 

use at the USFS Western Wildland Environmental Threat and Assessment Center at:

http://www.fs.fed.us/wwetac/threat_map/SeedZones_Intro.html

References

Campbell, R. K.; Sorensen, F. C. 1978. Effect of test environment on expression of clines and on 

delimitation of seed zones in Douglas-fir. Theoretical Applied Genetics 51: 233-246.

Daubenmire, R. F. 1942. An ecological study of the vegetation of southeastern Washington and 

adjacent Idaho. Ecological Monographs 12: 53-79.

Harris, G. A. 1967. Competitive relationships between Agropyron spicatum and Bromus 

tectorum. Ecological Monographs 37: 89-111.

Johnson, G. R.; Sorensen, F. C.; St. Clair, J. B.; Cronn, R. C. 2004. Pacific Northwest forest tree 

seed zones: a template for native plants? Native Plants Journal 5: 131-140.
GENETICS AND CLIMATE CHANGE

21

Kawecki, T. J.; Ebert, D. 2004. Conceptual issues in local adaptation. Ecology Letters 7: 1225-

1241.

St. Clair, J. B.; Kilkenny, F. F.; Johnson, R. C.; Shaw, N. L.; Weaver, G. 2013. Genetic variation 

in adaptive traits and seed transfer zones for Pseudoroegneria spicata (bluebunch wheatgrass) in 

the northwestern United States. Evolutionary Applications 6: 933-948.
GENETICS AND CLIMATE CHANGE

22

Project Title Conservation, Adaptation and Seed Zones for Key Great 

Basin Species

Project Agreement No. 14-IA-11221632-013

Principal Investigators and Contact Information

R. C. Johnson, Research Agronomist

USDA-ARS, Western Regional Plant Introduction Station

Washington State University

Box 646402

Pullman, WA 99164 

509.335.3771

rcjohnson@wsu.edu

Elizabeth Leger, Associate Professor of Plant Ecology

Department of Natural Resources and Environmental Science

Fleishmann Agriculture, Room 130

University of Nevada, Reno

775.784.7582

ealeger@gmail.com

Ken Vance-Borland, GIS Coordinator

Conservation Planning Institute 

NW Wynoochee Drive

Corvallis, OR 97330

kenvb@consplan.net

Project Description 

Native plant species are critical for wildlife habitat, livestock grazing, soil stabilization, and 

ecosystem function in the Western U.S. and the Great Basin. Yet current germplasm releases of 

these species do not specifically match natural genetic diversity with local climates, which often 

drive adaptation. Seed zones that match climate with genetic variation have been developed that 

will facilitate management decisions, ensure restoration with adapted plant material, and promote 

biodiversity needed for future natural selection with climate change. Over the course of this 

project seed zones have been completed and published for Tapertip onion (Allium acuminatum

Hook.), Indian ricegrass (Achnatherum hymenoides (Roem. & Schult.) Barkworth), Bluebunch 

wheatgrass (Pseudoroegneria spicata (Pursh) Á. Löve)) and Sandberg bluegrass (Poa secunda J. 

Presl (Johnson et al. 2012, 2013, 2015; St. Clair et al. 2013). This year seed zones have been 

completed for Basin wildrye (Leymus cinereus (Scribn. & Merr.) Á. Löve) and Thurber's 

needlegrass (Achnatherum thurberianum (Piper) Barkworth). Also, evaluation of plant traits for 

Sulfur-flowered buckwheat (Eriogonum umbellatum Torr.) in a common garden was initiated 

and will continue into 2016.
GENETICS AND CLIMATE CHANGE

23

Objectives

1. Collect key Great Basin species and establish common garden studies quantifying genetic 

variation in plant traits associated with phenology, production, and morphology.

2. Uncover adaptive plant traits in common gardens linked to seed source population 

climates and develop composite plant traits using multivariate statistics. 

3. Develop regression models linking composite plant traits with source climates and map 

seed zones to guide seed production of genetically appropriate plant material for 

restoration.

 

Thurber's needlegrass

Thurber's needle grass common gardens were established at Central Ferry, WA and Reno, NV in 

2010. The study consisted of 67 source populations predominantly from the Northern, Central 

Basin, and Range ecoregions. Data was collected in 2012 and 2013 on numerous phenology, 

production, and morphological traits. Analyses revealed extensive genetic variation in Thurber’s 

needlegrass across the Great Basin sampling region (Table 1). This was consistent with other 

grasses and forbs from the Great Basin and Intermountain West (Johnson et al. 2010, 2012, 

2013, 2015; St. Clair et al. 2013), and is generally observed in species’ other regions (St. Clair et 

al. 2005, Leimu and Fischer 2008, Horning et al. 2010). 

Traits were averaged over sites and years when correlations between specific traits were positive 

and significant (p <0.01), indicating considerable correspondence for plants growing in different 

environments. This process reduced traits from a potential of 48 for all site-year combinations 

(12 traits times 4 environments) to 24. These were used for canonical correlation with 17 

‘annual’ climate variables (Table 2) as defined by Wang et al. (2012). Canonical variates 1 and 2 

explained 60% of the total variation between plant traits and climate variables, 42% for variate 1, 

and 18% for variate 2 with p -values for canonical variate 1 and 2 of p <0.0002 and p <0.0424, 

respectively. No combination of variates were significant. Thus canonical variates 1 and 2 

established a strong link between genetic variation in common gardens and climate variables at 

source populations. 

Regression models with canonical variates 1 and 2 were exceptionally strong, explaining 94% 

and 87% of the variation in plant phenotypes, respectively. Thus, those canonical variates 

effectively represented the association of plant traits with different climates, and provided a 

strong basis for mapping seed zones. 

The seed zone map was derived by dividing the range of canonical scores predicted by 

regression models into segments and then overlaying the results. Regression with canonical 

scores for variate 1 was divided into 4 segments, and those for variate 2 into 3 segments resulting 

in an overlay with 12 seed zones (Figure 1). Canonical variate 1 was given somewhat more 

weight than variate 2 as it explained more of the total trait variation. 

These models were used to map 12 seed zones encompassing 465,079 km2in the Great Basin 

and surrounding areas. We recommend using these seed zones to guide restoration of Thurber’s 

needlegrass. Just six zones (4, 5, 7, 8, 11, and 12) represented 90% of the mapped area and 

predominated in semi-arid to arid climates. The wetter and cooler zones (1, 2, 3, and 6) 

represented only 6% of the mapped area. Zones 4, 7, and 10 had relatively small differences in 

climate, but with genetic variation it was enough to result in different seed zones. Still, those 

zones were often juxtaposed, suggesting potential coalescence could be considered by land 
GENETICS AND CLIMATE CHANGE

24

managers. Thus, the number of populations needed for restoration by zones is within practical 

limits. This has also been the case in other genecology studies on perennial bunchgrasses in the 

intermountain West (Johnson et al. 2010, 2012, 2015; St. Clair et al. 2013). Likely more limiting 

to seed availability of Thurber’s needlegrass then the number of seed zones are difficulties in 

seed cleaning presented by the extensive awns. Although initially more labor intensive, 

transplanting seedlings in one way to obtain more viable, surviving plants with fewer seeds.

Since the scope for future selective adaption and evolution depends on the availability of genetic 

variation, we also recommend numerous wild populations be collected and used as a restoration 

population within each seed zone. 

Basin wildrye

Collections of Basin wildrye were made in the Columbia Plateau in Washington state where 

octoploids are common, and in the Great Basin where both tetraploids and octoploids are found. 

We expected ploidy to have an important effect on ecological differentiation in relation to 

climate, so ploidy for all collections were determined as described by Jakubowski et al. (2011). 

The analysis of field collected sources revealed 57 octoploids and 52 tetraploids.

Common gardens of Basin wildrye were established at Pullman and Central Ferry, WA sites in 

2010 with plants from 109 wild populations plus the cultivars Trailhead (tetraploid) and Magnar 

Table 1. Summary of F-ratios and P-values from analyses of variance for Thurber’s needlegrass traits measured in 

common gardens at Central Ferry, WA and Reno, NV on source populations collected from the Great Basin over 

two years (2012 and 2013). 

Trait mean Site(S) Pop. (P) SxP Year(Y) YxS

F P F P F P F P F P

Phenology†

 Heading, day of year 135 27.9 <.01 8.9 <.01 2.01 <.01 187.6 <.01 27.8 <.01

 Blooming, day of year 133 17.2 <.01 6.9 <.01 1.8 <.01 78.8 <.01 2.0 0.16

 Maturity, day of year 161 36.1 <.01 3.4 <.01 1.47 0.01 2109.8 <.01 . .

Morphology‡

 Leaf length x width, cm21.64 263.2 <.01 4.2 <.01 1.47 0.01 125.4 <.01 147.4 <.01

 Leaf length to width 74.5 41.4 <.01 1.7 <.02 1.42 0.02 27.9 <.01 85.6 <.01

 Culm length, cm 37.0 715.2 <.01 3.2 <.01 2.67 <.01 98.6 <.01 0.3 0.56

 Panicle length, cm 12.2 3.9 0.07 4.7 <.01 2.32 <.01 30.7 <.01 7.2 <.01

 Awn length, cm 4.1 0.0 0.91 6.6 <.01 1.27 0.09 2.3 0.13 1.6 0.21

Production§

 Survival 0.71 11.2 <.01 6.5 <.01 3.01 <.01 54.9 <.01 11.0 <.01

 Panicle number 32.4 145.8 <.01 2.5 <.01 1.61 <.01 186.7 <.01 96.4 <.01

 Biomass, g 12.8 230.2 <.01 3.0 <.01 2.66 <.01 17.4 <.01 14.3 <.01

 Crown area, cm262.8 96.5 <.01 2.0 <.01 1.67 <.01 213.0 <.01 13.7 <.01

†Heading was at complete emergence of a lead panicle from its sheath, blooming was the initial appearance of anthers, and 

maturity when seed appeared mature in more than half the panicles. 

‡Leaf length and width were measured on the last fully emerged leaf of a lead culm after heading. Culm length, panicle length, 

and awn length (twice geniculate measured in three sections and summed) were measured on a lead culm after full extension.

§Panicles on each plant were counted after heading, harvest for dry weight was after maturity to within 4 cm of the soil, and 

after harvest, and crown area was estimated as the product of two perpendicular crown diameter measurements.
GENETICS AND CLIMATE CHANGE

25

(octoploid) were randomized in complete blocks with six replications. Data collection for 

phenology, production, and morphology traits was completed in 2012 and 2013. Data analyses 

indicated strong differences in ploidy and also in population within ploidy (Table 3). 

Octoploids had larger leaves, longer culms, and greater crown circumference than tetraploids but 

the numerical ranges of plant traits and their source climates overlapped between ploidy forms. 

Still, octoploids often had greater genetic variation for traits among collections and occupied 

more diverse climates than tetraploids. A single canonical correlation analysis linked climate and 

genetic variation for both ploidy types. Regression of canonical variates 1 and 2, which 

explained 70% of the variation, with seed source climate variables produced models that 

explained 64% and 38% of the variation, respectively, and were used to map 15 seed zones 

covering 673258 km2(Figure 2). Utilization of these seed zones will help ensure restoration with 

adaptive seed sources for both ploidy types. The higher trait variation and diverse climates 

occupied by octoploids suggests a higher capacity for adaptation than observed for tetraploids. 

Table 2. Plant and climatic traits used in canonical correlation of Thurber’s needlegrass growing 

at common gardens at Central Ferry (CF), WA and Reno (RE), NV in 2012 and 2013.

Final plant traits† Climatic traits

Heading Mean average temperature (MAT)

Blooming Mean warmest monthly temperature (MWMT)

Maturity CF Mean coldest monthly temperature (MCMT)

Maturity RE Continentality, MWMT-MCMT (TD)

Leaf length x width (leaf area) Mean Annual Precipitation (MAP)

Leaf length to width CF 2012 (leaf ratio) Mean summer precipitation (MSP)

Leaf length to width CF 2013 (leaf ratio) Annual heat moisture index, (MAT+10)/(MAP/1000)

Leaf length to width RE 2012 (leaf ratio) Summer heat moisture index ((MWMT)/(MSP/1000))

Leaf length to width RE 2013 (leaf ratio) Frost free period (FFP)

Culm length CF Day of year when FFP ends (FFPe)

Culm length RE Precipitation as snow (PAS)

Panicle length CF Extreme minimum temperature over 30 years (EMT)

Panicle length RE12 Extreme maximum temperature over 30 years (EXT)

Panicle length RE13 Hargreaves reference evaporation (Eref)

Awn length Hargreaves climatic moisture index (CMD)

Survival CF Mean annual solar radiation (MAR)

Survival RE Mean annual relative humidity (%)

Panicle number CF

Panicle number RE

Biomass CF

Biomass RE

Crown area CF

Crown area RE 2012

Crown area RE 2013

Sulfur-flowered buckwheat

Collection of Sulfur-flowered buckwheat was completed by the Western Regional Plant 

Introduction Station (WRPIS) in 2012 resulting in 21 accessions. There has also been ongoing 

collection through the BLM Seeds of Success (SOS) program resulting in 48 accessions. Seeds 

from the WRPIS and SOS collections were used to establish plants in the greenhouse in 2014. In 

the fall of 2014, these were transplanted to a common garden at the WRPIS farm at Pullman, 
GENETICS AND CLIMATE CHANGE

26

WA. The first year of data collection was completed in 2015. Taxonomy will be verified and

data collected continue in 2016 on phenology, production, and morphology plant traits in 2016.

Table 3. Summary of analyses for 109 Basin wildrye source populations growing in common 

gardens at Central Ferry and Pullman, WA in 2012 and 2013. 

Trait Ploidy

Population 

within ploidy Site Site x ploidy

Site x 

Population 

within ploidy 

________________________________________F (P-values)______________________________________________

Heading day 62.6 (<.002) 4.0 (<.003) 2082 (<.001) 15.5 (<.004) 1.5 (<.005)

Blooming day 61.7 (<.001) 3.7 (<.001) 1901 (<.001) 12.5 (<.001) 2.1 (<.001)

Maturity day 29.3 (<.001) 3.2 (<.001) 13376 (<.001) 2.5 (0.112) 1.3 (0.013)

Morphology

Leaf weight 472 (<.001) 10.3 (<.001) 16.8 (0.002) 18.9 (<.001) 2.4 (<.001)

Leaf ratio 0.16 (0.69) 1.8 (<.001) 0.21 (0.65) 0.12 (0.72) 0.94 (0.64)

Leaf area 359 (<.001) 11.0 (<.001) 21.7 (0.001) 25.9 (<.001) 2.7 (<.001)

Specific leaf wt. 108 (<.001) 2.3 (<.001) 3.9 (0.076) 2.9 (0.088) 1.5 (<.001)

Culm length 150 (<.001) 2.8 (<.001) 20.2 (<.001) 1.3 (0.25) 1.5 (0.001)

Head length 22.0 (<.001) 3.0(<.001) 11.1 (0.007) 0.0 (0.95) 1.7 (<.001)

Production

Survival 41.4 (<.001) 2.0 (<.001) 46.3 (<.001) 14.2 (<.001) 2.6 (<.001)

Head number 64.0 (<.001) 2.2 (<.001) 0.7 (0.44) 19.1 (<.001) 1.9 (<.001)

Crown circum. 272 (<.001) 6.0 (<.001) 7.7 (0.019) 71.2 (<.001) 3.1 (<.001)
GENETICS AND CLIMATE CHANGE

27

Figure 1. Proposed seed zones for Thurber’s needlegrass resulting from an overlay of 

canonical scores from regression models of canonical variates 1 and 2 with climate 

variables in the Great Basin. The canonical variates were derived from canonical 

correlation of plant traits and climate variables. Ecoregion boundaries are shown as 

black lines. Model predictions outside two times the data range for observed values of 

canonical scores were not mapped, and are shown in white. 
GENETICS AND CLIMATE CHANGE

28

Figure 2. Proposed seed zones for basin wildrye based on regression models of canonical variates 

1 and 2 with climate variables over intermountain west. The canonical variates were derived from 

canonical correlation of plant traits and climate variables. Ecoregion boundaries are shown as 

red lines. Model predictions outside the data range for observed values of canonical scores were 

not mapped, and were shown in white. 
GENETICS AND CLIMATE CHANGE

29

Management Applications and Seed Production Guidelines

 Maps visualizing the interaction of genetic variability and climate for restoration species 

allow informed decisions regarding the suitability genetic resources for restoration in 

varying Great Basin and Southwestern environments. 

 The recommended seed zone boundaries may be modified based on management 

resources and land manger experience without changing their basic form or the 

relationship between genetic variation and climate.

 We recommend utilization of multiple populations of a given species within each seed 

zone to promote the biodiversity needed for sustainable restoration and genetic 

conservation.

 Collections representing each seed zone should be released, grown, and used for ongoing 

restoration projects.

Publications

Espeland, E. K.; Perkins, L. B.; Horning, M. E.; Johnson, R. C. [Accepted August 2015]. Seed 

production farms affect germination and emergence of native grass materials: the source by 

planting environment interaction. Crop Science: (Accepted 5 August 2015).

Johnson, R. C.; Horning, M. E.; Espeland, E.; Vance-Borland, K. 2015. Genetic variation and 

climate interactions of Poa secunda (Sandberg bluegrass) form the Intermountain Western 

United States. Evolutionary Applications 8: 172-184.

Dugan, F. M.; Cashman, M. J.; Johnson, R. C.; Wang, M.; Chen, X. 2014. Differential resistance 

to Stripe rust (Puccinia striiformis) in collections of Basin wild rye (Leymus cinereus). Plant 

Health Progress 15: 34-38.

Presentations

Johnson, R. C. 2015. Seed zones for Sandberg bluegrass and friends. Great Basin Consortium 

Conference; 16-18 February; Boise, ID.

Products

 Seed zones are for key Great Basin restoration species to ensure plant materials used for 

restoration are adapted, suitable, and diverse.

 Collection and conservation of native plant germplasm though cooperation between 

National Plant Germplasm System (NPGS), the Western Regional Plant Introduction 

Station, Pullman, WA, the U.S. Forest Service, and the Seeds of Success (SOS) program 

under BLM. This ensures availability of native plant genetic resources that otherwise 

may be lost as a result of disturbances such as fire, invasive weeds, and climate change.

References

Horning, M. E.; McGovern, T. R.; Darris, D. C.; Mandel, N. L.; Johnson, R. 2010. Genecology 

of Holodiscus discolor (Rosaceae) in the Pacific Northwest, U.S.A. Restoration Ecology 18: 

235-243.
GENETICS AND CLIMATE CHANGE

30

Jakubowski, A. R.; Jackson, R. D.; Johnson, R. C.; Hu, J.; Casler, M. D. 2011. Genetic diversity 

and population structure of Eurasian 1 populations of reed canarygrass: cytotypes, cultivars, and 

interspecific hybrids. Crop and Pasture Science 62: 982-991.

Johnson, R. C.; Erickson, V. J.; Mandel, N. L.; St. Clair, B.; Vance-Borland, K. W. 2010. 

Mapping genetic variation and seed zones for Bromus carinatus in the Blue Mountains of 

Eastern Oregon, U.S.A. Botany-Botanique 88: 725-736.

Johnson, R. C.; Cashman, M. J.; Vance-Borland, K. 2012. Genecology and seed zones for Indian 

Ricegrass across the Southwest USA. Rangeland Ecology and Management 65: 523-532.

Johnson, R. C.; Hellier, B. C.; Vance-Borland, K. W. 2013. Genecology and seed zones for 

tapertip onion in the U.S. Great Basin. Botany 91: 686-694.

Johnson, R. C.; Horning, M. E.; Espeland, E.; Vance-Borland, K. 2015. Genetic variation and 

climate interactions of Poa secunda (Sandberg bluegrass) from the Intermountain Western 

United States. Evolutionary Applications 8: 172-184.

Leimu, R.; Fischer, M. 2008. A meta-analysis of local adaptation in plants. PLoS One 3(12): 

e4010.

St. Clair, J. B.; Mandel, N. L.; Vance-Borland, K. W. 2005. Genecology of Douglas fir in 

western Oregon and Washington. Annals of Botany 96: 1199-1214.

St. Clair, J. B.; Kilkenny, F. F.; Johnson, R. C.; Shaw, N. L.; Weaver, G. 2013. Genetic variation 

in adaptive traits and seed transfer zones for Pseudoroegneria spicata (bluebunch wheatgrass) in 

the northwestern United States. Evolutionary Applications 6: 933-948.

Wang, T.; Hamann, A.; Spittlehouse, D. L.; Murdock, T. Q. 2012. ClimateWNA–Highresolution spatial climate data for western North America. Journal of Applied Meteorology and 

Climatology 51: 16-29.
GENETICS AND CLIMATE CHANGE

31

Project Title Ecophysiological Analyses of Common Gardens to 

Inform Seed Transfer Guidelines

Project Agreement No. 11.IA.11221632.098 & 14.IA.11221632.012 

Principal Investigators and Contact Information 

Matthew Germino, Supervisory Research Ecologist

USDI U.S. Geological Survey

Forest and Rangeland Ecosystem Science Center

970 Lusk Street, Boise ID 83702

208.456.3353

mgermino@usgs.gov

Martha Brabec, Biological Sciences Technician

USDI U.S. Geological Survey

Forest and Rangeland Ecosystem Science Center

970 Lusk St

Boise, ID 83706

208.426. 5207, Fax 208.426.5210

mbrabec@usgs.gov

Bryce Richardson, Research Geneticist 

USDA Forest Service

Rocky Mountain Experimental Station

735 North 500 

East Provo, UT 84606

801.356.5112

brichardson02@fs.fed.us

Project Description

Determining how different seed sources, or plant provenances, vary in their physiological 

response to climate is an important component of common-garden studies and contributes 

substantially to the basis for seed-transfer guidelines for restoration. We are measuring a 

comprehensive set of variables that provide relatively quick insight on how seed provenances of 

foundational restoration species, specifically sagebrush species and bluebunch wheatgrass 

(Pseudoroegneria spicata), differ in their climate responses. Measurements focus on how 

different populations from around the Great Basin vary in their threshold responses or resistances 

to water and temperature stresses. Publications from 2015 demonstrate the importance of seed 

sources for initial establishment of sagebrush, along with the importance of associated 

management treatments such as herbicides, mowing, and seeding herbs. A large dataset of 

physiological, morphological, and anatomical traits of seedlings or adult plants at GBNPP 

common gardens around the Great Basin continues to be developed.
GENETICS AND CLIMATE CHANGE

32

Introduction

Increased wildfire activity poses a major challenge for big and low sagebrushes (Artemisia sp.) 

communities. Seeding and plantings of sagebrushes and desirable bunchgrasses, such as 

bluebunch wheatgrass, have been extensive and will continue as a central part of the Department 

of Interior Secretarial Order #3335. However, restoration success has been mixed. Climate and 

weather variability, appropriateness of seeds, and site conditions relating to management are all 

factors that may help explain success of sagebrush restoration efforts. Consideration of these 

factors may improve seeding or planting success and therefore they are the focus of our GBNPP 

research and extension/outreach.

We are continuing to develop techniques and applications for laboratory capable high-throughput 

“phenotyping” of the many plants in GBNPP gardens in the Great Basin. Measurement of a 

greater variety of functional traits in individual plants or populations increases the objectivity of 

assessments of climate adaptation. This increases the reliability of conclusions about which 

processes and climate parameters most limit plant establishment and distinguish different seed 

sources. Our measurements focus on traits that relate to temperature and water stress, which are 

the dominant factors affecting plant establishment in the cold deserts of the Great Basin. Several

of our measurements quantify threshold temperatures or water levels for plant survival.

Objectives

1) Provide quantitative and standardized analyses of climate adaptation for plants in common 

gardens in the Great Basin. 

2) Determine how the climate adaptation varies among populations, subspecies or cultivars, 

seed zones, and species.

Methods

Our efforts are done in close collaboration with Bryce Richardson, who performs lab tests for 

sagebrush identification and established some of the big sagebrush gardens we work on, and with 

Francis Kilkenny, Holly Prendeville, Brad St. Clair, Matt Fisk, and others who facilitate our 

measurements on their bluebunch wheatgrass common gardens.

For our overall GBNPP efforts, we have devised a “sequential filtering” approach to isolating 

factors affecting survival and establishment. We quantify variation in ecophysiological traits of 

the following aspects of populations in common gardens:

 At the native site (i.e., measured upon seed collection).

 In common nursery settings (i.e., in cone-tainer stock without strong environmental 

selection).

 After acclimation to garden sites has occurred, but before post-planting mortality has 

occurred (while maladapted plants are culled, allow us to identify which plant 

climate/weather parameters are most important).

 After appreciable culling and selection have occurred (identifies the ecophysiological 

trait values that confer survival or mortality, and their specific climate drivers).

This approach is partially applied to sagebrushes and is being fully applied to bluebunch 

wheatgrass. Assessing trait variation before and after environmental stress and mortality greatly 

increases what can be learned about climate adaptation beyond measurements of growth and 

survival, and can provide key insight within a few years of garden planting (contrasting the many 
GENETICS AND CLIMATE CHANGE

33

years typically required to learn from survival of garden outplants). The resulting ecophysiology 

information will corroborate, or refine, the specific climate parameters most appropriate for seed 

zones. Furthermore, this information will provide data that can help refine the selection of 

temperature or precipitation increments with which to separate seed zones. 

Our screening protocol across populations and gardens of each species includes: 

1. Carbon isotopes as an indicator of differences in water use efficiency and stress.

2. Pressure-volume relationships to identify minimum water status thresholds.

3. Freezing point and photosynthetic resistance to freezing (and heating; temperature 

thresholds).

4. Standard allometric measures that indicate growth strategy, inform interpretation of 

ecophysiological variables, and relate to water and temperature responses (e.g., 

specific leaf area, wood density).

Bluebunch Wheatgrass 

Prior to outplanting, we measured stable isotopes of carbon to estimate differences in 

photosynthetic water-use efficiency and specific leaf area (which entails a direct tradeoff of 

stress mitigation vs. photosynthesis). Following outplanting, we are using three different 

sampling schemes across some, or all, of the 16 gardens established by Kilkenny et al.: 

1) Extensively, across all 16 gardens, we are using stable isotopes of carbon to estimate 

differences in photosynthetic water-use efficiency, specific leaf area, and leaf width.

2) In four gardens that vary considerably in temperature, we are measuring freezing 

avoidance (temperature causing ice formation, lowered in cold-adapted/acclimated 

plants), and freezing resistance (temperature causing a 50% reduction in chlorophyll 

fluorescence). Gardens from warmest to coldest are Central Ferry, WA; Orchard, ID; 

Richfield, ID; and Baker, OR.

3) Intensive effort at Orchard, ID is assessing differences in photosynthesis, water status, 

phenology, chlorophyll fluorescence (a measure of stress response), and leaf curling (a 

stress avoidance mechanism).

Big Sagebrush

Two studies are referred to here: Brabec et al. (2015) and Brabec et al. (in review, which is from 

the Brabec thesis (2014)). We established common gardens of young seedlings in the Birds of 

Prey National Conservation Area in Idaho, including: 1) five replicate gardens for physiological 

measurements and frequent survival counts to enable correlation of survival with weather 

(Brabec et al. 2015), and 2) replicate gardens in areas that had been treated with herbicide, 

mowing, or drill seeding (Brabec et al. in review and 2014). 

One of the most significant outcomes of these experiments with young sagebrushes was the 

development of a new statistical approach that enables learning from mortality patterns in 

seedings. Many planting or seeding trials in the Great Basin have few surviving plants owing to 

harsh growing conditions, and most often nothing is learned from the trials- as is common with 

negative results in general. The temperature or precipitation/moisture parameters that often 

coincide with mortality are rarely incorporated with mortality because standard Cox survival 

statistics cannot incorporate time-varying factors, such as weather data. We were able to 

overcome this limitation by adding logistic models to analyze survival-weather relationships. 
GENETICS AND CLIMATE CHANGE

34

New Sagebrush Seed Collections and Common Gardens

We made over 10 seed collections from Wyoming big sagebrush and low sagebrushes on the 

2015 Soda Wildfire, and several more assisting the Idaho Fish and Game’s lead collections on 

other sites. For all seed sources, we verified the identity of the sagebrush using morphology and 

leaf chemical traits. 

Expected Results and Discussion

In the Brabec et al. (2015) study, mowing the site prior to planting seedlings led to greater initial 

survival probabilities for sagebrush outplants, except where seeding also occurred, and these 

effects were related to corresponding changes in bare soil exposure (Table 1). Initial survival 

probabilities were >30% greater for the local population of big sagebrush relative to populations 

imported to the site from typical seed transfer distances of ~320-800 km (199-497 mi) (Table 1). 

In the Brabec 2014 and Brabec et al. (in review) studies: 1) A.t. wyomingensis had the most 

growth and survival, and tetraploid populations had greater survival and height than diploids. 

Seasonal timing of mortality varied among the subspecies/cytotypes and was related more to 

minimum temperatures rather than water deficit, and 2) temperatures required to induce ice 

formation were up to 6° C more negative in 4n-A.t. tridentata and A.t. wyomingensis than other 

subspecies/cytotypes, indicating greater freezing avoidance. In contrast, freezing resistance of 

photosynthesis varied only 1° C among subspecies/cytotypes, being greatest in A.t. 

wyomingensis and least in the subspecies normally considered most cold-adapted, A.t. vaseyana. 

A large spectrum of reliance on freezing-avoidance vs. freezing-tolerance was observed and 

corresponded to differences in post-fire survivorship among subspecies/cytotypes. Differences in 

water-deficit responses among subspecies/cytotypes were not as strong and did not relate to 

survival patterns. 

Table 1. Coefficients of sagebrush seedling survival model results from outplantings into treatment plots 

(averaged across treatments) at the Birds of Prey National Conservation Area (BOP NCA). Hazard ratios 

>1 indicate increased hazards of death relative to the base level of the explanatory variable (i.e., similar to 

a relative death rate). The base level is unseeded control for the treatment factor and the local Idaho seed 

source for the population factor. Seed sources and their mean annual temperatures and precipitation were 

as follows: 1) Idaho, BOP NCA, 10.8° C / 297 mm · yr-1, diploid, 2) New Mexico, San Luis Mesa, 9.9° C 

/ 265 mm · yr-1, tetraploid, 3) California, near Benton, 8.9° C / 250 mm · yr-1, diploid, 4) Oregon, near 

Echo, 11.5° C / 239 mm · yr-1, diploid (from Brabec et al. 2015).

Variable Parameter 

Estimate

Hazard 

Ratio SE z p-Value

Population: California 0.487 1.628 0.156 3.120 0.002

Population: New Mexico 0.276 1.318 0.153 1.800 0.072

Population: Oregon 0.260 1.298 0.154 1.690 0.090

Seeded -0.160 0.852 0.220 -0.730 0.467

Mowed -0.634 0.530 0.218 -2.920 0.004

Mowed x Seeded 0.797 2.219 0.309 2.580 0.010

Herbicide 0.066 1.068 0.221 0.300 0.765

Herbicide x Seeded -0.430 0.650 0.311 -1.380 0.166

Mowed+Herbicide -0.200 0.819 0.219 -0.910 0.361

Mowed+Herbicide x Seeded 0.708 2.029 0.314 2.250 0.024
GENETICS AND CLIMATE CHANGE

35

We concluded from the Brabec 2014 and Brabec et al. (in review) studies that low-temperature 

responses are a key axis defining climate adaptation in young sagebrush seedlings and vary more 

with cytotype than with subspecies, which contrasts the traditional emphases on 1) water 

limitations to explain establishment in these deserts, and 2) on subspecies in selecting restoration 

seedings. These important and novel insights on climate adaptation are critical for seed selection 

and parameterizing seed transfer zones, and were made possible by incorporating weather data 

with survival statistics. 

Management Applications and/or Seed Production Guidelines

The combination of our ecophysiological measurements with growth and survival of sagebrushes 

or perennial grasses in common gardens provides key insights for seed selection. Our tests 

clearly indicate geographic transfer of seed can have important effects on survival (Brabec et al. 

2015). Physiological avoidance and tolerance of freezing varies considerably among different 

populations of big sagebrush, justifying a focus on minimum temperatures in seed transfer 

guidelines (Brabec 2014, Brabec et al. in review). 

Our preliminary data on bluebunch wheatgrass will provide key insight on 1) the relative 

importance of winter/cold compared to summer/drought to adaptation and which climate 

parameters most distinguish seed sources, and 2) if/how the empirically determined seed zones 

(based on phenology, leaf width, and plant height) differ in physiological climate adaptation; and 

how the very commonly used cultivars differ from natural seed sources in response to 

temperature stress and water deficit.

Finally, many plantings or seedings in the Great Basin fail with no lessons learned, but the 

survival/weather statistics used here could be applied to any restoration plantings to enable 

adaptive management. 

Presentations

Germino, Matthew. 2015. Climate, weather, and sagebrush seed sources: experimental insights 

on challenges and opportunities. The Right Seed in the Right Place at the Right Time: Tools for 

Sustainable Restoration; 13 May; webinar series. 

Germino, Matthew. 2015. Climate adaptation in dominant plants of the sagebrush steppe. 

Seminar to Department of Biological Sciences; 1 October; Boise, ID.

Brabec, Martha; Germino, Matthew; Richardson, Bryce. 2015. Response of seedlings of each big 

sagebrush subspecies to experimental warming reveals importance of minimum temperatures to 

establishment. GBNPP session at the Great Basin Consortium, 4th annual meeting; 17-19

February; Boise, ID.

Germino, Matthew; Brabec, Martha; Raymondi, Ann Marie; Richardson, Bryce. 2015. Climate 

adaptation of big sagebrush revealed from success of 24 historic post-fire seedings: insights for 

assisted migration. GBNPP session at the Great Basin Consortium, 4th annual meeting; 17-19 

February; Boise, ID.

Richardson, Bryce A.; Chaney, Lindsay; Shaw, Nancy L.; Germino, Matthew J. 2015. Clines in 

growth, seed yield and survivorship among subspecies of big sagebrush: relationships to climate 
GENETICS AND CLIMATE CHANGE

36

and development of seed transfer zones. Great Basin Consortium, 4th annual meeting; 17-19 

February; Boise, ID. Poster.

Abstract: Plant species that occupy large geographic distributions contend with highly varied 

climates. Such climatic differences frequently require genetic adaptation. Failure to understand 

how these species are adapted to climate will impede restoration. In this study we assess the 

growth, seed yield and survivorship of big sagebrush (Artemisia tridentata subspecies tridentata, 

vaseyana, and wyomingensis) from three common gardens over four years. Using linear-mixed 

models (growth and seed yield) and survivor analysis (survivorship), trait variation is associated 

with source-location derived climate variables (temperature, precipitation, and their interactions). 

Seed yield and growth showed similar significant clines affected by summer dryness and winter 

precipitation. Seed yield and growth climate models were highly correlated (r = 0.73, p <0.0001). 

However, survivorship showed clines affected by winter temperatures and the ratio of winter to 

summer precipitation. Overall, continentality strongly affects climate adaptation in big 

sagebrush. We discuss the development of seed transfer zones based on these data.

Brabec, Martha; Germino, Matthew; Richardson, Bryce; Shinneman, Doug; McIlroy, Susan; 

Arkle, Robert. 2015. Response of young sagebrush seedlings to management of herbs. Great 

Basin Consortium, 4th annual meeting; 17-19 February; Boise, ID. Poster.

Abstract: Seeding or planting of big sagebrush in post-fire rehabilitation or restoration projects 

involves alteration of a variety of plant community, soil, and site conditions. Herbicide 

application, mowing, drill seeding with forbs and grasses, and combinations of any of these 

treatments often happen with or before seeding or out-planting big sagebrush, and could affect 

herb competition or hydrological conditions for successful sagebrush establishment. The 

objective of this study was to evaluate how initial establishment of big sagebrush seedlings is 

influenced by management treatments on the herb layer, and to determine how these effects vary 

among different populations (seed sources) of big sagebrush. Results suggest that seedling 

survival may be negatively affected by land management treatments that alter the herb layer and 

soil surface, including drill seeding. Survival probabilities were relatively greater for the local 

and fast-growing populations of big sagebrush relative to other populations in an extremely dry 

spring at the lower edge of the sagebrush steppe ecosystem (Birds of Prey National Conservation 

Area in Southwestern Idaho).

Germino, Matthew J.; Davidson, Bill; Brabec, Martha; Halford, Anna. 2015. Establishing islands 

of sagebrush in an early-seral, post-fire landscape: effects of topographic position, cluster 

plantings, and artificial microclimate shelters. Great Basin Consortium, 4th annual meeting; 17-

19 February; Boise, ID. Poster.

Abstract: Methods to increase post-fire restoration of big sagebrush are needed, particularly in 

relatively dry regions of its range where annual exotic and other early seral grasses and harsh 

wind exposure often prevail. Patchy establishment of sagebrush within such landscapes is 

increasingly recognized as an appropriate target for restoration or rehabilitation treatments. We 

planted replicate clusters of Wyoming Big Sagebrush seedlings using the collaborative nursery 

and planting team and research area designation in the Birds of Prey National Conservation Area 

in Idaho. Over 1000 seedlings were planted over many hectares. One year after planting, survival 

was near 90% in drainages, 65% on slopes, and 40% on flat areas. Use of straw wattle, snow 

fences, or both to decrease windspeed reduced survival from 60% to as low as 23%, contrary to 
GENETICS AND CLIMATE CHANGE

37

our expectations. There were no effects of planting clusters in rows or grids of various sizes and 

configurations. Insect defoliation was inversely related to survival and was as high as 70% of 

foliage. Whereas wind sheer is presumed to be a stress factor for sagebrush in this relatively flat 

landscape, we did not find evidence for it. Instead, our data suggests that targeting certain 

topographic positions and allowing for non-uniform and non-random post-fire establishment may 

be realistic.

Publications 

Brabec, Martha; Germino, Matthew; Pilliod, David; Shinneman, Doug; McIlroy, Susan; Arkle, Robert. 

2015. Challenges of establishing Big sagebrush (Artemisia tridentata) in rangeland restoration: effects of 

herbicide, mowing, whole-community seeding, and sagebrush seed sources. Rangeland Ecology & 

Management 68(5): 432-435. 

Brabec, M.; Germino, M.; Richardson, B. [Revision submitted November 2015]. Climate adaption and

post-fire restoration of a foundational perennial in cold desert: insights from intraspecific variation in 

response to weather. Journal of Applied Ecology. (Submitted).

Additional Products 

 We made many seed collections from Wyoming Big Sagebrush (and, unwittingly, Basin 

big sagebrush, as inferred from diploid status) and early sagebrush (A. longiloba) in and 

around the 2015 Soda Wildfire sites, and assisted the Idaho Fish and Game (led by 

Michael Young) on 5 Saturday volunteer collection days. We made voucher specimens and 

confirmed taxonomic identity at all collection sites.

 Assessment of all in-house sagebrush seed sources at Lucky Peak Nursery (fall 2015) and 

of all sources from the 2014 and 2015 BLM seed buys to be applied on the Soda Wildfire 

site.

 Consultations on Soda Fire rehabilitation and monitoring, to BLM and FWS, five meetings 

with BLM and partner groups, and six phone discussions/interviews.

 Developed proposals that leverage GBNPP research, specifically to the Department of 

Interior FWS “SSP” program and to Joint Fire Sciences Program.

 Invited presentations on soil stability and restoration in field tours on Soda Fire site, for 

20-30 BLM and partner agency staff (including DOI Assistant Secretary Janice Schneider).

 Lead organizer of Great Basin Consortium meeting (GBC#4), February 2015 in Boise.

 Initiated, motivated, and arranged incorporation of GBNPP into the GBC.

 Conceived of and convened symposia on “Restoration of Dry Sites” and “Water in the 

Desert” and combined poster-oral presentation sessions involving GBNPP research at 

GBC#4.

 Developed high-throughput protocols for assessing freezing point, resistance, carbon 

isotopes, and other plant traits.

 Discovery and first-time application of tools for learning about factors contributing to 

establishment of seedlings even when plantings or seedings are not successful, drawn from 

epidemiology and applied to sagebrush seedling common gardens (in review at Journal of 

Applied Ecology).

 Cover feature article in Rangeland Ecology and Management (Brabec et al. 2015).

 Quoted or featured in three articles on the topics of GBNPP common gardens of big 

sagebrush, sagebrush seeding, and climate change in rangelands, all through Associated 
GENETICS AND CLIMATE CHANGE

38

Press, and disseminated in the Idaho Statesman newspaper (main paper for Boise, ID) and 

others nationally.

 Serving on several committees regarding native plant materials for restoration for the 

Department of Interior secretarial order #3336.

 Participant in the Department of Interior 2015 Weed Summit meeting (November 17-19, 

Boise, ID).
GENETICS AND CLIMATE CHANGE

39

Project Title Species and Population-Level Variation in Germination 

Strategies of Cold Desert Forbs

Project Agreement No. 10-CR-11221632-174

Principal Investigators and Contact Information

Elizabeth Leger, Associate Professor of Plant Ecology

Dept. of Natural Resources and Environmental Science

University of Nevada

MS 186

Reno, NV 89557 

775.784.7582, Fax 775.784.4789

eleger@cabnr.unr.edu

Sarah Barga, PhD Student

Dept. of Natural Resources and Environmental Science

University of Nevada

MS 186

Reno, NV 89557 

306.528.7368, Fax 775.784.4789

sarahcatherinebarga@gmail.com

Project Description

Background

Native forbs are an important component of sagebrush plant communities and provide resources 

for native pollinators and other wildlife in these systems. Native forbs not only provide forage 

and cover to native wildlife, they also potentially suppress annual invasive plants such as 

cheatgrass (Bromus tectorum). Degraded sagebrush communities often lack this important plant 

component, and active restoration may be required to return forbs to altered communities. 

Though germination requirements of some forb species have been investigated, many native 

forbs from the Great Basin are unstudied. The lack of information about the germination 

strategies of many cold desert forbs makes it difficult for growers to increase seeds of these 

species, and difficult for land managers to successfully incorporate herbaceous species into their 

restoration protocols.

Increasing our knowledge of species-specific germination strategies of native forbs can inform 

seed increase protocols, the choice of restoration species in different areas, and the relative 

importance of local seed sourcing for different species. The seed germination of forbs can be 

more challenging than germination of many grasses, and exposing forb seeds to their preferred 

dormancy breaking conditions can dramatically increase their germination success. In addition, 

different species express different amounts of within-species variation in germination cues, 

which may positively correlate with the importance of local seed sourcing for a species. 
GENETICS AND CLIMATE CHANGE

40

In our continuing work, we are attempting to identify environmental variables and other factors 

that are correlated with population-level variation in germination strategies, which might allow 

for generalizations about species for which information is lacking. For example, we may find 

more population-level variation in species with larger geographic ranges, or less variation in 

species that occupy only very specific set of environmental conditions. Creating range maps for 

potential restoration species is the first step in the process of identifying these key environmental 

variables. We used herbarium data to create fine-scaled range maps that can be used for this 

purpose, as well as provide indications of suitable habitat for restoration with this important 

component of sagebrush steppe ecosystems. 

Figure 1. Seeds of forb species used in this experiment, from left to right: Mentzelia albicaulis, 

Chaenactis douglasii, Blepharipappus scaber, Phacelia hastata, Crepis intermedia, Cryptantha 

pterocarya, Microsteris gracilis, Collinsia parviflora, Gilia inconspicua, and Agoseris 

grandiflora. 

Objectives

The main objective of this project was to assess the seed germination strategies of ten cold desert 

forbs (Fig. 1), including identifying their dominant germination strategies and their level of 

within-species variation in germination cues. We determined seed germination requirements for 

some common species that have not yet been studied and identified species which possess high 

levels of seed dormancy.

We were also interested in whether there is a relationship between population-level variation at a 

small scale and environmental variability at a large scale. For example, do species with high 

environmental variability across their range experience a higher degree of population-level 

variation in germination strategies? 

Methods

Seed Germination Experiment

This study focused on ten species of annual and short-lived native forbs that are commonly 

found in sagebrush steppe ecosystems and are of interest due to their potential importance as a 

food source for sage-grouse during early life stages. Species investigated were: Agoseris 

grandiflora (bigflower agoseris), Blepharipappus scaber (rough eyelashweed), Chaenactis 

douglasii (Douglas' dustymaiden), Collinsia parviflora (blue eyed mary), Crepis intermedia 

(limestone hawksbeard), Cryptantha pterocarya (wingnut cryptantha), Gilia inconspicua (shy 

gilia), Mentzelia albicaulis (whitestem blazingstar), Microsteris gracilis (slender phlox), and

Phacelia hastata (silverleaf phacelia). 

Seeds were collected from multiple populations in the vicinity of Reno, NV and Carson City, NV 

in the spring and summer of 2013. Seeds were placed in petri dishes on wet germination paper, 

and treatments varied after-ripening temperatures (either room temperature or 40° C) and 

exposure to wet, cold conditions (2° C for 0, 2, 4, or 6 weeks) before placement in a moderate 
GENETICS AND CLIMATE CHANGE

41

(15° C) temperature in a factorial design, with each treatment replicated in five dishes. These 

treatments were designed to determine if seeds require warm or cold temperatures to break 

dormancy, which are both common dormancy mechanisms in desert plants. The Survival

package within Program R (2.12.2) was used to perform survival analysis using the germination 

data.

Range Mapping

We created range maps for each of our ten species using herbarium data from online resources. 

We used points from the Intermountain Region Herbarium Network, the Jepson Herbarium, and 

The University of Washington’s Burke Museum Herbarium in order to acquire points from 

across the entire range of each species. We limited our points to those representing plants that 

were found from 1950 to the present. With our collaborator Tom Dilts, University of Nevada, 

Reno, we tabulated 29 biologically relevant variables for use in our range models, including: 

annual and seasonal minimum temperatures, maximum temperatures, precipitation, and annual 

temperature range. We also calculated actual evapo-transpiration (AET), potential evapotranspiration, climate water deficit (CWD), water supply (WS), and soil water balance (SWB) 

(see Dilts et al. 2015 for methods). We used these variables directly in our model and also used 

them to calculate other complex variables based on bioclimatic variables (Booth et al. 1989) for 

use in our models, including: water from the soil (i.e., water remaining from previous years -

ratio of SWB:AET), water from the sky (i.e., precipitation as snow or rain from a given year’s 

events - ratio of AET:SWB), relative drought (ratio of PET:AET), precipitation seasonality (the 

coefficient of variation of monthly precipitation), annual water use efficiency (ratio of WS:AET), 

cumulative unused water (positive difference between WS and the greater of either AET or 

SWB), relative unused water in the spring (ratio of water supply to AET or SWB, whichever is 

higher, for spring season only), and atmospheric source of moisture (positive difference between 

AET and SWB). We created these variables using climate data from PRISM for the past 64 years 

(Daly et al. 2008), along with soil, elevation, and data for other topographic variables (aspect, 

slope, etc.). We mapped the ranges for each of the species using Maxent modeling and ArcMap 

10.1 software. We prepared the points for modeling by verifying point location information, 

thinning points using a 20 kilometer buffer, creating a bias file for unequal sampling across 

states, and splitting the points into training (65%) and test (35%) samples. We performed model 

optimization using Maxent software by running factorial combinations of all feature types and 

regularization multipliers. We performed model selection using Area Under the Curve (AUC) 

values and AIC values. We are using county maps for each of our species from the Biota of 

North American Plants website as a coverage guide for our range maps and calculating omission 

error and standard deviation maps to examine model fit. 

Results and Discussion

Species varied in preference for after ripening temperature and cold stratification, and our ten 

focal species represented a variety of germination strategies (Table 1). Hot after-ripening 

stimulated earlier germination in A. grandiflora, M. gracilis, and P. hastata; however, the total 

number of germinated seeds did not differ between after-ripening treatments. Cool after-ripening 

resulted in both earlier and higher total number of germinated seeds for C. douglasii. Species 

with high levels of germination during cold stratification (potential fall germinators) included: A. 

grandiflora, B. scaber, C. parviflora, C. pterocarya, and M. gracilis. Other species germinated 

best in warmer temperatures after exposure to cold, including: B. scaber, C. douglasii, C. 

intermedia, and P. hastata. Those that germinated best when placed directly into 15o C included 

M. albicaulis and G. inconspicua.
GENETICS AND CLIMATE CHANGE

42

Using survival analysis, we found differences among species in both the timing of germination 

and the overall quantity of germinated seeds based on different treatments (Fig. 2). We identified 

four generalist species (A. grandiflora, C. parviflora, C. pterocarya, and M. gracilis) that 

germinated under a broad range of conditions, and others that possess high levels of dormancy, 

including G. inconspicua, M. albicaulis, and P. hastata (Fig. 2). While seed dormancy is a 

strategy that can increase plant fitness over longer time scales, it can be undesirable when 

restoration outcomes depend on seed germination over shorter time scales. We also identified 

population level differences in germination strategies for nine out of ten of our study species, 

although some differences were more dramatic than others (Fig. 3). Collinsia parviflora was the 

only species that did not experience population-level differences in germination strategies, 

perhaps due to the fact that it is a broad generalist. This high level of population-level 

differentiation may indicate that seeds may possess germination strategies that are closely 

associated with the environmental conditions at their collection location, or they may be the 

result of genetic drift. Field plantings would be required to differentiate between these two 

possibilities.

Additionally, we have created potential habitat maps for each of the focal species included in this 

study (Fig. 4). While some of the maps closely parallel the ranges predicted by the county maps 

provided by the Biota of North American Plants database (www.bonap.org), others still require 

optimization. We found only 19 of the 29 variables included in our modeling efforts were highly 

predictive of the range for any of our species though some variables (precipitation in summer, 

winter, and spring, a relative drought index, and winter maximum temperatures) were important 

for multiple species (Table 2). In addition, although species responded similarly to a specific 

variable, no two species were predicted by the same combination of variables. We will use these 

maps in future research to identify which environmental characteristics are correlated with 

A) B)

Figure 2. Examples of survival analysis using the results of cold stratification for A) a generalist 

species, and B) a species with high dormancy. As the colored lines decline from left to right, 

they indicate an increase in total seed germination with time. Almost all C. pterocarya seeds 

germinated under every treatment combination, while almost no M. albicaulis seeds germinated 

under any treatment.
GENETICS AND CLIMATE CHANGE

43

variation within a species. Specifically, we are asking whether higher levels of variation in 

different environmental variables over the range of a species are correlated with increased 

population-level variation in germination requirements. 

Management Applications

Screening plants for their ability to tolerate a variety of field growing conditions will provide 

seed developers with promising species to add to production fields. Further, knowledge about 

species-specific germination preferences can help managers identify methods for incorporating 

native forbs into restoration protocols and help growers germinate seeds of species with high 

levels of dormancy. 

This work has provided information on how to germinate forb species of interest for improving 

sage-grouse nesting habitat, which has the potential to improve recruitment success in areas 

where food resources are limiting for chick development. Additionally, the population-level 

differences in germination strategies we observed confirms that seed collection source can have a 

large influence on restoration outcomes. In the case of the forb species studied here, it would be 

possible to select populations with different degrees of dormancy, and managers should be aware 

of this possibility when selecting seeds for increase. 

Finally, our area of occupancy maps provide new information on likely habitat for these 

important sagebrush steppe species, and can help provide information on appropriate habitat for 

seeding these forbs in areas where surveys may be lacking, or in highly disturbed sites where no 

evidence remains of the former native forb community. 

Figure 3. Example of survival analyses showing dramatic population-level difference for an annual 

(Blepharipappus scaber) and a perennial (Crepis intermedia) species studied in this experiment. As 

the colored lines decline from left to right, they indicate an increase in total seed germination with 

time.

A) B)
GENETICS AND CLIMATE CHANGE

44

Table 1. Results of germination experiment for three populations per species and estimated area of 

occupancy estimations based on modeling efforts. For spring germinators, “Cold” indicates that the 

species would germinate better after being seeded in the fall, so it can experience winter conditions, and 

“No Cold” indicates that it would germinate better if it were seeded in the spring. Habitat area is based on 

our current best Maxent model for each species; values may change as models are refined.

Species

After 

Ripening

Winter 

Germ.

Spring 

Germ.

Variation 

Among 

Pops.

Life 

Form

Habitat 

Area (km2)

Agoseris 

grandiflora

Hot Yes Yes Yes Peren. 483,160

Blepharipappus 

scaber

None Yes No Yes Ann. 257,126

Chaenactis 

douglasii

Cool No Yes, 

Cold

Yes Peren. 1,400,344

Collinsia 

parviflora

None Yes Yes No Ann. 1,507,658

Crepis intermedia None No Yes, 

Cold

Yes Peren. 1,599,704

Cryptantha 

pterocarya

None Yes Yes Yes Ann. 805,189

Gilia inconspicua None No Yes, No 

Cold

Yes Ann. 1,082,895

Mentzelia 

albicaulis

None No Yes? Yes Ann. 1,792,732

Microsteris 

gracilis

Hot Yes Yes Yes Ann. 1,663,505

Phacelia hastata Hot No Yes? Yes Peren. 1,388,650

*Germ. = Germination; Pops. = populations; Peren. = perennial; Ann. = annual
GENETICS AND CLIMATE CHANGE

45

Table 2. Model variables most predictive of area of occupancy for focal species represented by four letter 

codes, separated by A) water-related variables, and B) temperature-related variables. Minus signs (-) 

represent negative relationships, plus signs (+) represent positive relationships, blank indicates no 

association, and “mid” indicates an asymptotic relationship. Variables with threshold values, meaning there 

is a specific value at which the species increases or decreases dramatically, are indicated with “T.” A list 

of the environmental variables included in the models can be found in the Methods section. 

A. Water-related variables Species Sum ppt Fall ppt Win ppt Spr ppt Cum drought Rel drought Season ppt Culm soil water Water from 

skyWater from soilAnnual water use efficiencyUnused water

AGGR - -

BLSC - - -

CHDO - - - -

COPA T+ T + T +

CRIN - - -

CRPT T + T -

GIIN T - -

MEAL T + T -

MIGR T + + T + T +

PHHA

*Ppt = precipitation; Sum = Summer (June, July, August), Fall = September, October, November; Win = Winter 

(December, January, February); Spr = Spring (March, April, May); Cum drought = cumulative drought; Rel 

drought = relative drought; Season ppt = Seasonality of precipitation; Culm soil water = cumulative soil water.

B. Temperature-related variables Species Fall min temp Win min temp Win max temp Spr min temp Spr max temp Min 

tempTemp range

AGG

R

+

BLSC mid

CHD

O

COP

A

T -

CRIN

CRPT mid

GIIN mid + -

MEA

L

MIG

R

T + mid

PHH

A

mid +

*Temp = temperature; Min = minimum; Max = maximum; see Table A for other abbreviations.
GENETICS AND CLIMATE CHANGE

46

Figure 4. Examples of habitat maps for a perennial (Agoseris grandiflora) and an annual 

(Microsteris gracilis) species included in this study created using herbarium records and 

Maxent modeling.

Presentations

Barga, Sarah. 2015. Estimating the geographic distribution of cold desert forbs using Maxent. 

Ecology, Evolution, and Conservation Biology Program Ecolunch; 4 December; Reno, NV.

Barga, Sarah; Leger, Elizabeth A. 2015. Germination strategies and geographic distribution of 

cold desert forbs. Nevada Native Plant Society meeting; 4 October; Reno, NV. 

Barga, Sarah; Leger, Elizabeth A. 2015. Species and population-level variation in germination 

strategies of cold desert forbs. National Native Seed Conference; 13-16 April; Santa Fe, NM.

Barga, Sarah; Leger, Elizabeth A. 2015. Species and population-level variation in germination 

strategies of cold desert forbs. Great Basin Native Plant Project Annual Meeting; 17-19 

February; Boise, ID.

References

Booth, Trevor H.; Searle, Suzette D.; Boland, Douglas J. 1989. Bioclimatic analysis to assist 

provenance selection for trials. New forests 3(3): 225-234.

Daly, Christopher; Halbleib, Michael; Smith, Joseph I.; Gibson, Wayne P.; Doggett, Matthew K.; 

Taylor, George H.; Curtis, Jan; Pasteris, Phillip P. 2008. Physiographically sensitive mapping of 

climatological temperature and precipitation across the conterminous United States. International 

Journal of Climatology 28(15): 2031-2064.

Dilts, Tom E.; Weisberg, Peter J.; Dencker, Camie M.; Chambers, Jeanne C. 2015. Functionally 

relevant climate variables for arid lands: a climate water deficit approach for modeling desert 

shrub distributions. Journal of Biogeography 42(10): 1986-1997.
GENETICS AND CLIMATE CHANGE

47

Project Title Dynamics of Cold Hardiness Accumulation and Loss

in Sulphur-flower Buckwheat (Eriogonum

umbellatum)

Project Agreement No. 13-JV-11221632-066

Principal Investigators and Contact Information

Anthony S. Davis, Associate Professor

College of Natural Resources

University of Idaho

P. O. Box 441133

Moscow, ID 83844

208.885.7211

asdavis@uidaho.edu

Matthew R. Fisk, Graduate Student and Biological Science 

Technician (Plants)

University of Idaho and USDA Forest Service

Rocky Mountain Research Station Grassland, Shrubland and 

Desert Ecosystems Research Program 

322 E. Front St.

Boise, ID 83702

208.373.4358

mfisk@fs.fed.us

Kent G. Apostol, Associate Extension Agent

Forest Health Gila County Cooperative Extension

University of Arizona

PO Box 2844

Payson, AZ 85547-2844

928.472.5286

kapostol@email.arizona.edu

Project Description

Objectives

Cold hardiness, defined as the capacity of a plant tissue to survive exposure to freezing 

temperatures, is variable across species geographic distribution and annual seasonality. It is a 

well-known indicator of species tolerance and distribution ranges and limits. This is an

important factor to consider in Great Basin restoration work as diurnal and seasonal

temperature fluctuations within the region can be extreme. Knowing where the thresholds of

temperature tolerances lie within individual species is a key component in determining 

population and regional potential for restoration success.

The current research goals are to provide a streamlined strategy for plant producers and 
GENETICS AND CLIMATE CHANGE

48

restoration specialists in the Great Basin to test cold hardiness of forb species and specific 

genetic sources in an effort to provide better guidelines for developing and testing seed zones,

as well as producing a greater understanding of the influence of changing climatic conditions

on plant populations. Using common and valuable candidate Great Basin species, we are

working with public and private collaborators to build a short guide to cold hardiness. This 

will greatly enhance our ability to both understand the role cold temperatures play in native

plant establishment following planting, as well as potential implications of changing climatic 

conditions for restoration in the Great Basin.

Materials and Methods

Sulphur-flower buckwheat (Eriogonum umbellatum) is a common, native, valuable subshrub 

whose natural range covers much of the Great Basin region. It has been selected for initial 

investigation to help provide the basis for understanding seasonal cold tolerance accumulation 

and loss within Great Basin native species.

In the fall of 2006 a sulphur-flower buckwheat common garden consisting of seventeen

distinct populations was established in Boise, ID (Figure 1). In October 2013, five accessions 

of the surviving populations were selected as representatives for the species geographic

distribution (Table 1). From these five specific accessions, we examined different aspects of 

the species, including geographical range, longitudinal seed production, seed zones, 

ecoregions, and elevational and longitudinal gradients. A sixth population component was 

also added to the study. This sixth component was designed to include one original wildland 

collection site from the five selected accessions growing in the common garden to evaluate 

localized effects on populations.

Figure 1. Sulphur-flower buckwheat common garden located in Boise, ID.
GENETICS AND CLIMATE CHANGE

49

Table 1. Sulphur-flower buckwheat population site details.

The freeze-induced electrolyte leakage (FIEL) technique was deployed to evaluate the cold 

tolerance of leaf tissue samples. Index of injury, that is the relative amount of electrolytes

leaked, was calculated across a range of temperatures and used to determine LT50 values. LT50,

the temperature at which 50% of cell damage occurs, was selected as the basis of population 

comparison. Tissue samples were collected from the field across an entire calendar year,

starting in October 2013 on a 6 week cycle. Nine sets of samples were collected and processed

to complete the year. All samples were transported to Moscow, ID for processing at the

University of Idaho Seedling Quality Assessment laboratory. Sample collection and 

processing all took place within 48 hours. Figure 2 shows variation in leaf morphology 

between the different populations and tissue sample selection and processing for evaluation. 

Data Analysis and Results

Using the calculated Index of Injury for each sample, statistical models were designed to 

calculate LT50 values based on fitting 3-parameter logistic sigmoidal functions to each plant.

Repeated measure analysis of variance was used to identify significance between the 

collection date*population, Tukey’s honest Significance test was deployed to separate means 

describing differences between populations within sample dates (Figure 3), and a two-way 

analysis of variance was conducted to compare location effects on cold hardiness between the 

common garden and the wildland site as well as differences between the two October sample 

dates. 

Results indicate geographic, seasonal, and date*population interaction differences among 

accessions. Statistical significance was found between the two October collection periods and 

the wildland / common garden location. 

Between the populations there was a low LT50 cold hardiness resistance level ranging from -

10 to -16o C during the spring collection months and a high LT50 cold hardiness resistance 

level raining from -56 to -58o C in December (Table 2). December was the sample collection 

that appeared to be the most cold resistant, whereas April – August months tended to all be 

similar in their lack of cold hardiness resistance.

Future Plans

The remaining tissue samples from field collections not used in the FIEL tests have been oven 

dried, organized, and stored with the future potential to further investigate cold tolerance 
GENETICS AND CLIMATE CHANGE

50

acclimation and loss via carbohydrate analysis or other means. These types of analysis are not 

time sensitive and can be completed at any future date. Interest in further investigation will be 

based on the results from the FIEL work.

A Master’s thesis and manuscripts are expected to come out of this work in 2016. 

Management Applications and/or Seed Production Guidelines

The techniques from this work can easily be deployed to other species. Upon further 

investigation on plant materials across geographic distributions, we will be able to determine

the degree to which cold hardiness results can be extrapolated and applied across species and 

populations. This project will provide a streamlined strategy for plant producers and

restoration specialists in the Great Basin to test cold hardiness of native species, particular 

genetic sources, and other plant materials in an effort to provide better guidelines for 

developing and testing seed zones. These techniques will also provide a greater understanding 

of the influence of changing climatic conditions on plant distributions. In order to fill major 

knowledge gaps, there is a definite need for further developed guidelines on cold hardiness.

Table 2. LT50 high and low values for nine sampling dates from October 

25, 2015 to October 16, 2015 for five ERUM populations at the Boise 

Common Garden.

ERUM Population

M J B C W

-

o C

LT50 low 10 14 16 13 16

LT50 high 56 56 56 56 58
GENETICS AND CLIMATE CHANGE

51

Figure 2. Left photo shows variation in size of healthy, complete representative Eriogonum 

umbellatum leaves from five common garden populations and one wildland site used for cold 

hardiness investigation. Three photos on the right show sampling selection of a leaf and sampled 

discs used in freezing tolerance evaluation.
GENETICS AND CLIMATE CHANGE

52

Figure 3. October 2013 - October 2014 population M, J, B, C, and W LT50 Tukey’s honest 

significance (HSD) mean separation box and whisker plots for Eriogonum umbellatum. Mean 

values not sharing a letter within population differ significantly at P <0.05. Whiskers represent 

standard error of the mean (SEM).
GENETICS AND CLIMATE CHANGE

53

Presentations

Fisk, M. F. 2015. The right plants, in the right place, at the right time: a decade’s effort in native 

plant materials development and restoration research in the Great Basin (and beyond). Idaho 

Outdoor Association Meeting; 2015 May 12; Boise, ID.

Fisk, M. F.; Davis, A. S.; Apostol, K. G.; Shaw, N. L. 2015. To freeze or not to freeze? An 

investigation into sulphur-flower buckwheat. Great Basin Consortium Conference; 2015 

February 17-19; Boise, ID.

Instructor

Fisk, M. F. 2015. Native plants: selection-collection-processing. Tree Nursery Improvement 

Project - Target Plant Concept Workshop; 2015 March 1-5; Amman, Jordan.
GENETICS AND CLIMATE CHANGE

54

Project Title Morphological and Genetic Characterization of Blue 

Penstemon (Penstemon cyaneus)

Project Agreement No. 15-JV-11221632-181

Principal Investigators and Contact Information 

Mikel R. Stevens, Professor

Department of Plant and Wildlife Sciences

Brigham Young University

5131 LSB

Provo, UT 84602 

801.422.4032, Fax 801.422.0008

mikel_stevens@byu.edu 

Robert L. Johnson, Associate Research Professor

Department of Biology

Brigham Young University

3115A MLBM

Provo, UT 84602

801.422.7094, Fax 801.422.0093

robert_johnson@byu.edu 

Project Description

Introduction

Blue penstemon (Penstemon cyaneus Pennell) is considered a valuable forb for revegetation and 

restoration uses in the Great Basin region (Winslow 2002, Shaw et al. 2004). Research on blue 

penstemon irrigation and propagation has been conducted to develop cultural practices that 

contribute to seed production (Winslow 2002, Tilley et al. 2012, Shock et al. 2014); however, to 

our knowledge, there has not been a systematic assessments of blue penstemon genetic diversity 

across the landscape. 

Blue penstemon has a latitudinal range over 350 miles with an elevational distribution between 

4700 and 8700 ft. The species as a whole has adapted across a broad and varied ecological range 

occurring from sagebrush steppe to spruce-fir forest. These adaptations can potentially impact 

restoration success if seed origins are not considered and genetic ecotypes not defined. It is 

important to identify appropriate germplasm sources of blue penstemon for restoration use within 

specific Great Basin regions to: 1) maximize potential establishment success by matching 

appropriate genotypes with restoration sites, 2) ensure sufficient genetic variation to allow for 

natural selection and adaptation posts revegetation (e.g. climate change effects), 3) minimizing 

the possibility of out-breeding depression (genetic swamping), and 4) identifying collections 

with greatest potential for commercial seed production (McKay et al. 2005, Broadhurst et al. 

2008, Bushman et al. 2010).
GENETICS AND CLIMATE CHANGE

55

Objectives

Our objectives in this study are to: 1) characterize the morphological variation in blue 

penstemon, and 2) gain an understanding of the genetic variation within the taxon. To achieve 

these objectives we will collect both tissues and seeds from wild plant populations. Seeds will be 

used for common garden evaluation which will provide vital data for the morphological 

questions we are aiming at evaluating. Plant tissues will be used for molecular genetic analysis in 

order to assess genetic variation across the range of P. cyaneus. It is anticipated that this project 

will take approximately four years to complete.

It is our intention to collect up to 50 collections of blue penstemon across its known ecological 

and geographical distribution. Herbarium records reveal the occurrence of blue penstemon in 23 

counties in central Idaho, two in Montana, and four in Wyoming. It is our objective to collect 

samples scattered across this entire region. The collected seed will be used to assess phenotypic 

variation between the collected accessions of blue penstemon. We will establish at least two 

common gardens in separate sites representing unique geographies and climates. At present, we 

have tentative agreements to plant one garden at the Aberdeen, ID Research and Extension 

Center, in cooperation with Dr. Stephen Love, and a second at the Brigham Young University 

Life Science Greenhouses field plots in Provo, UT. These common gardens will be used not 

merely as additional replications, but to quantitatively measure the interaction between genotype 

and environment.

The field of molecular genetics is rapidly changing in a minimum of two ways. First, the cost to 

accomplish an objective is steadily declining, and second the depth in which a question can be 

probed is greatly increasing; but, so is the cost to analyze the resulting data. Application of 

molecular techniques such as amplified fragment length polymorphism (AFLP), simple sequence 

repeats (SSRs or microsatellites), and genotype by sequencing (GBS) have all demonstrated the 

ability to genotype large numbers of samples (Hardesty et al. 2008; Bushman et al. 2010; Elshire 

et al. 2011). These techniques vary in the amount of effort required and the depth of information 

provided; however, the cost for doing the most powerful technique mentioned, that is, GBS, has 

steadily decreased and the computational requirements to do such a project are now available at 

Brigham Young University (BYU). While the costs are essentially the same per sample with 

each of these techniques, GBS provides much higher resolution for each sample by orders of 

magnitude. Therefore, the objective of this portion of the study will be to use GBS, unless, other 

more cost effective methods are developed. In using these techniques we will assess the genetic 

variation in order to determine if specific genotypes exist and if those genotypes are correlated 

both geographically and with morphological traits that may have value in plant restoration. 

Methods

At each of the wild collection sites we collected 4-6 young healthy leaves (200 mg dry weight) 

from at least eight plants and preserved them in the freezer in silica gel desiccant. A 

representative specimen from each site was preserved as a voucher to correlate genetic variation 

with morphological variation and confirm taxon identity. Voucher specimens will be deposited at 

the Stanley L. Welsh Herbarium, Brigham Young University. Seed was also harvested from 

multiple plants at each site for the common garden trial. The collected seed will be used to 

establish at least two common gardens in separate sites. Each common garden will be a 

completely randomized block design with four replicated blocks. Each block will consist of five 

plants from each seed collection site. Replications within each common garden will provide a 

range of phenotypic measurements for each trait at each seed collection site. The differences 
GENETICS AND CLIMATE CHANGE

56

between the common garden sites for each seed collection site will allow us to quantify the 

interaction of genotype by environment for each phenotypic trait. The measurements we will 

take will include survival, days to flower, number of flowering stems, number of flowers per 

inflorescence, seed production, leaf area of last vegetative node, and plant height at maturity. 

Information relating to the genetic population structure and diversity of blue penstemon is 

critical to wisely proceed in the germplasm development for seed production for reseeding uses 

in revegetation projects. In this study we are investigating either using GBS or a closely related 

genomic reduction technique such as RADseq (restriction associated DNA sequencing), or GRRSC (genomic reduction based on restriction-site conservation), (Maughan et al. 2009; Peterson 

et al. 2012). Once we have the molecular data we will then analyze it with Bayesian clustering 

analysis and related computational analytic tools. 

Expected Results and Discussion

The molecular data in combination with the common garden results planned in this study will 

allow for the identification of morphological and genetically differences in native blue 

penstemon populations. We will then correlate genetic, morphology, and geography aspects of 

this study in population genetic studies. It is anticipated that the common garden evaluations 

combined with molecular characterization, followed by the population genetic statistical studies 

will allow us to make recommendations for approaches to seed collecting, germplasm 

development, and seed increases for use in land reclamation and native community restoration 

throughout the northern Great Basin.

References

Broadhurst, Linda M.; Lowe, Andrew; Coates, David J.; Cunningham, Saul A.; McDonald, 

Maurice; Vesk, Peter A.; Yates, Colin. 2008. Seed supply for broadscale restoration: maximizing 

evolutionary potential. Evolutionary Applications 1(4): 587-597. 

Bushman, B. Shaun; Bhattarai, Kishor; Johnson, Douglas A. 2010. Population structures of 

Astragalus filipes collections from western North America. Botany-Botanique 88(6): 565–574.

Elshire, Robert J.; Glaubitz, Jeffrey C.; Sun Qi, Poland; Jesse A., Kawamoto; Ken, Buckler; 

Edward S.; Mitchell, Sharon E. 2011. A robust, simple genotyping-by-sequencing (GBS) 

approach for high diversity species. PLoS One 6(5): e19379. 

Hardesty, B. D.; Hughes, S. L.; Rodriguez, V. M.; Hawkins, J. A. 2008. Characterization of 

microsatellite loci for the endangered cactus Echinocactus grusonii, and their cross-species 

utilization. Molecular Ecology Resources 8(1): 164-167.

Holmgren, Noel H. 1984. Penstemon. In: Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, 

Noel H.; Reveal, James L.; Holmgren, Patricia K., eds. Intermountain flora: vascular plants of 

the Intermountain west. Bronx, NY: New York Botanical Garden: 370-457.

McKay, John K.; Christian, Caroline E.; Harrison, Susan; Rice, Kevin J. 2005. “How local is 

local?” - A review of practical and conceptual issues in the genetics of restoration. Restoration 

Ecology 13(3): 432-440.
GENETICS AND CLIMATE CHANGE

57

Maughan, Peter J.; Yourstone, Scott M.; Jellen, Eric N.; Udall, Joshua A. 2009. SNP Discovery 

via Genomic reduction, barcoding, and 454-pyrosequencing in Amaranth. The Plant Genome 

2(3): 260-270.

Peterson, Brant K.; Weber, Jesse N.; Kay, Emily H.; Fisher, Heidi S.; Hoekstra, Hopi E. 2012. 

Double digest RADseq: an inexpensive method for de novo SNP discovery and genotyping in 

model and non-model species. PLoS One 7(5): e37135.

Shaw, Nancy L.; Lambert, Scott M.; DeBolt, Ann M.; Pellant, Mike. 2004. Increasing native 

forb seed supplies for the Great Basin. In: Dumroese, R. K.; Riley, L. E.; Landis, T. D., comp. 

National proceedings: Forest and Conservation Nursery Associations-2004; 2004 July 12–15; 

Charleston, NC; and 2004 July 26–29; Medford, OR. Proc. RMRS-P-35. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station: 94-102.

Shock, Clinton C.; Feibert, Erik B. G.; Saunders, Lamont D.; Shaw, Nancy; Sampangi, Ram S. 

2014. Irrigation requirements for native perennial wildflower seed production in a semi-arid 

environment. Ann. Rep. 2013. Corvallis, OR: Oregon State University Agricultural Experiment 

Station, Malheur Experiment Station: 166-183.

Tilley, Derek; St. John, Loren; Ogle, Dan; Shaw, Nancy. 2012. Plant guide: Blue penstemon, 

Penstemon cyaneus Pennell. Aberdeen, ID: U.S. Department of Agriculture, Natural Resources 

Conservation Service, Aberdeen Plant Materials Center. 3 p.

Winslow, Susan R. 2002. Propagation protocol for production of Penstemon cyaneus seeds, 

[Propagation Protocol Database]. Reforestation, Nurseries, and Genetic Resourses. Available: 

http://www.nativeplantnetwork.org/Network/ViewProtocols.aspx?ProtocolID=1173/ 

?searchterm=penstemon cyaneus [accessed 23 December 2015].
GENETICS AND CLIMATE CHANGE

58

Project Title A Field Test of Local Adaptation in Bluebunch 

Wheatgrass (Pseudoroegeneria spicata)

Project Agreement No. 15-JV-11221632-174

Principal Investigators and Contact Information

Kathryn Alexander, Graduate Research Assistant

College of Forestry

Oregon State University

3180 SW Jefferson Way

Corvallis, OR 97333

541.973.4303

kathryn.alexander@oregonstate.edu

Matt Orr, Assistant Professor, Biology

Oregon State University-Cascades

2600 NW College Way 

Bend, OR 97701

541.771.8846 

Matt.orr@osucascades.edu

Ron Reuter, Associate Professor

Oregon State University-Cascades

2600 NW College Way

Bend, OR 97703

541.322.3109

ron.reuter@oregonstate.edu

Francis Kilkenny, Research Biologist

USDA Forest Service

Rocky Mountain Research Station

322 E Front Street Suite 401

Boise, ID 83702

208.373.4376, Fax 208.373.4391

ffkilkenny@fs.fed.us
GENETICS AND CLIMATE CHANGE

59

Brad St. Clair, Research Geneticist

USDA Forest Service

Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7294, Fax 541.750.7329

bstclair@fs.fed.us

Holly Prendeville, Research Geneticist

USDA Forest Service

Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7300, Fax 541.750.7329

hollyprendeville@fs.fed.us

Project Description

Introduction

The early developmental stages (germination - seedling growth) associated with bluebunch 

wheatgrass are poorly understood within the context of restoration and local adaptation. While 

many functional trait studies focus on linking adult plant traits with resource use and acquisition, 

the progression through early development stages may have a large impact on overall restoration 

outcomes (Larson et al. 2015). In addition, the impact of soils on early development and local 

adaptation is poorly understood. For this project, we will examine this species’ early 

development traits, phenological variation in seed production, and local adaptation to soil 

texture. Our project is part of a larger effort designed to test the efficacy of seed zones in 

bluebunch wheatgrass (Kilkenny and St. Clair 2014). By examining the early development traits 

of bluebunch wheatgrass in more detail, it may be possible to uncover additional mechanisms of 

local adaptation and maximize the effectiveness of seed zones in the restoration setting. 

Additionally, this study will help land managers to better understand the life history and 

morphological traits underpinning population differences and plant fitness.

The overriding goal for these three complementary studies (i.e. early development, phenology, 

and soils) is to support or refine the seed zones developed for bluebunch wheatgrass, and to gain 

a more nuanced understanding of the species’ adaptation to local conditions. This enhanced 

understanding will add to the knowledge base for this species in particular, and the study of local 

adaptation in general. By adding to this body of knowledge, land managers will have more tools 

with which to carry out effective restoration. In particular, the early development study will help 

land managers better understand the link between local adaptation and early development of 
GENETICS AND CLIMATE CHANGE

60

these plants in the field, the phenology study will help to improve the cultivation protocols for 

bluebunch wheatgrass, and the soils study has the potential to refine the existing seed zones 

which will then be more effective.

Objectives

Our hypothesis is that bluebunch wheatgrass populations sourced and grown at a test site within 

a previously delineated seed transfer zone will exhibit early developmental traits that indicate 

greater fitness than populations gathered from other zones. We also hypothesize that declines in 

plant fitness will correlate with increasing soil and climatic differences among sites. Lastly, we 

hypothesize that a single-pass approach to harvest in the seed production setting will limit the 

genetic diversity of the harvest and may impair the future survival of these propagules in restored 

areas.

This research will accomplish the following: 1) a detailed understanding of the early 

development traits of bluebunch wheatgrass (both above and below ground), and how these traits 

vary within and among the bluebunch wheatgrass seed zones, 2) seed harvest protocol 

recommendations for seed producers that a selects for the most genetically diverse seeds, and 3) 

an overview of soil variability among bluebunch wheatgrass seed zones and an understanding of 

how soil texture and water holding capacity contribute to local adaptation and early success of 

this species.

Methods

For the early development study, we will propagate 810 plants in a greenhouse setting that, as a 

whole, represent four seed zones comprising the greatest land area within the range of the 

species. The seeds from each zone will include collections from three different populations 

within each zone and will be representative of the northern and southern portions of the seed 

zones. Seeds will be placed in sand-filled propagation tubes and grown for 10 days after 

germination. The seedlings will then be removed from growth tubes and roots cleaned. Each 

plant will be imaged with a high definition scanner and analyzed using image analysis software 

to measure root and leaf morphology. A stomatal impression will be taken from the center of the 

longest leaf on each plant to quantify stomatal density. Lastly, the plant will be divided into 

leaves and roots using a razor blade and dried. Once dry, each portion of the plant will be 

weighed separately to determine the leaf and root biomass. We will perform an analysis of 

variance to determine if there are significant trait differences between seedlings that were grown 

within one seed zone and/or different zones.

To determine the range of flowering and seed maturity dates for bluebunch wheatgrass we will 

monitor each individual in an on-going, common garden experiment. The common garden was 

planted with 39 populations from eight seed zones and two propagated lines (Anatone and 

Goldar) for a total of 820 plants surrounded by two rows of buffer plants. We will record when 
GENETICS AND CLIMATE CHANGE

61

each plant develops flowers, when seeds are produced and become mature, and when these seeds 

are dispersed. The data will be analyzed to determine the range of dates when mature seeds are 

present for propagules within each seed zone. Using this information, we will make seed zone 

specific recommendations for growers that maximize seed collection volume and genetic 

diversity.

To better understand the role soils play in terms of local adaptation, we will collect bluebunch 

wheatgrass seeds from native populations as well as representative soil samples from the top 15 

cm at each collection site. Collections will be made within one or more seed zones in Central 

Oregon. The soils will be textured using the Particulate Organic Matter method (Kettler et al. 

2001), and the USDA’s soil texture calculator. The soil water holding capacity will also be 

measured in the field. The soils from each collection area will be homogenized and placed into 

pots to be used as a growth medium. The bluebunch wheatgrass seeds will then be grown 

outdoors starting in fall 2016 and monitored for germination and pre-frost survival. The plants 

will then be monitored for spring germination and survival after winter dormancy. An analysis of 

variance will be used to determine if there are differences in traits that correspond to soil texture 

and water holding capacity.

Expected Results and Discussion

We expect to find that the variability in certain early developmental traits such as root to shoot 

ratio, leaf length, stomatal density, early survival, and germination can be partially explained by 

local adaptation. We also expect to find that geographic distances over which these phenomena 

occur correspond to the empirically delineated seed zones for bluebunch wheatgrass and the soil 

gradients that exist within and among these zones. By measuring these traits in detail, we will be 

able to determine how large an impact local adaptation has on the early development and 

survival of this species. This information will serve to strengthen the justification for, and the 

applicability of, these seed zones in the restoration setting. Additionally, by exploring the 

variability in seed production timing, and making meaningful suggestions to seed growers about 

how to capture the greatest possible genetic diversity, we expect that the resulting restored 

populations will have enhanced fitness and long-term survival in the field. The three studies 

proposed here will answer questions regarding the early development of bluebunch wheatgrass, 

and how local adaptation, soils, and propagation protocols may impact restoration outcomes.

References

Kettler, T. A.; Doran, J. W.; Gilbert, T. L. 2001. Simplified method for soil particle-size 

determination to accompany soil-quality analyses. Soil Science Society of America Journal 

65(3): 849.
GENETICS AND CLIMATE CHANGE

62

Kilkenny, F.; St. Clair, B. 2014. Testing the efficacy of seed zones for re-establishment and 

adaptation of bluebunch wheatgrass (Pseudoroegneria spicata). In: Kilkenny, Francis; Shaw, 

Nancy; Gucker, Corey. 2014. Great Basin Native Plant Project: 2013 Progress Report. Boise, ID: 

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 222 p.

Larson, Julie E.; Sheley, Roger L.; Hardegree, Stuart P.; Doescher, Paul S.; James, Jeremy J. 

2015. Seed and seedling traits affecting critical life stage transitions and recruitment outcomes in 

dryland grasses. Journal of Applied Ecology 52(1): 199-209.
GENETICS AND CLIMATE CHANGE

63

Project Title Genetic and Environmental Regulation of Functional 

Traits: New Approaches for Restoration in a Changing 

Climate

Project Agreement No. 15-JV-11221632-203

Principal Investigators and Contact Information 

Brad Butterfield, Assistant Research Professor

Northern Arizona University

Dept. of Biological Sciences

617 S. Beaver St.

PO Box 5640

Flagstaff, AZ 86011-5640

928.853.0359, Fax 928.523.7500

Bradley.Butterfield@nau.edu

Troy Wood, Research Ecologist

U.S. Geological Survey

Colorado Plateau Research Station

Flagstaff, AZ 86011-5614

928.523.7704, Fax 928.523.7500

twood@usgs.gov

Project Description

Introduction

Identifying genetically suitable native plant materials for specific restoration sites and 

establishing populations that can persist under climate change are two critical challenges facing 

ecological restoration efforts. Climate change in particular means that “local is best” may not be 

true in the future. Effective solutions to these problems have included common garden and 

genecology studies used to develop seed transfer zones or transfer functions for individual 

species (Kilkenny 2015). However, extending such species-specific analyses, which have been 

conducted for relatively few focal groups, to the thousands of other important restoration species 

is difficult. Because of funding constraints, and because climate impacts on plant populations 

have already begun, it is critical to develop methods that rely on detailed analyses of workhorse 

species but that can be extended to other important restoration taxa.

One way to extend common garden research is through identification of the functional traits 

associated with local adaptive divergence among populations in existing common gardens. Plant 

performance is mediated by functional traits – organismal characteristics that determine 

responses to the local environment (Lavorel and Garnier 2002). We know that there are strong 

relationships between functional traits and the environment (Wright et al. 2004; Swenson et al. 

2011). However, we know little about which functional traits are relatively genetically 

constrained, and which are more plastic; a distinction that is critical for development of seed 

transfer guidelines.
GENETICS AND CLIMATE CHANGE

64

Objectives

We have shown that specific leaf area (SLA), a critical integrator of the “leaf economics 

spectrum” (Wright et al. 2004), exhibits significant broad-sense heritability among populations 

of Bouteloua gracilis (blue grama grass) grown in a common garden, and is strongly correlated 

with source location temperature (Butterfield and Wood 2015). While population-specific SLA 

may serve as a good indicator of suitable climate niche in this species, more data are needed 

from a reasonable sample of model restoration species. Whether such easy to measure functional 

traits can be used to predict habitat suitability of different seed sources for many species, both 

under current and future climates, remains an open question.

To this end, our specific objectives are to:

 Conduct a meta-analysis of broad-sense heritability in functional traits of grasses.

 Perform measurements of root traits on multiple species and populations in a common 

environment.

Methods

A literature search for functional trait measurements on multiple populations of a species in a 

common environment has been conducted. This literature search has yielded more than 50 

studies with suitable data, which includes at a minimum of: (1) information on the source 

locations of the experimental populations in order to extract data on the source environment from 

WorldClim (Hijmans et al. 2005), and (2) population mean values for functional traits. These 

data will be used to assess correlations between functional traits and source environment. The 

strength of the correlations will be positively related to the ratio of between- versus withinpopulation trait variance, which is in turn proportional to broad-sense heritability. More direct 

estimates of broad-sense heritability will be calculated when sufficient data are provided (means 

and variances for each population) in order to support the correlative data. Confidence intervals 

for correlation coefficients will be back-transformed from Fisher’s-Z estimates, and grand means 

and confidence intervals will be calculated from the correlation coefficients to determine: (1) 

which functional traits exhibit greater or lesser broad-sense heritability, and (2) the 

environmental dependence of that heritability.

When available, existing common gardens will be used to measure a suite of aboveground 

functional traits. An additional experiment will be conducted with plants grown in containers in a 

common environment in order to measure root and whole-plant functional traits as well (Table 1). 

Leaf and stem traits will be measured on several stems of each plant sampled, and root traits (if 

not detrimental to primary study goals) will be measured on tissues sampled with small diameter 

soil cores. Methods will follow Perez-Harguindeguy et al. (2013). Two analyses will be conducted 

on each trait for each species. First, analysis of variance will be used to assess significant genetic 

differentiation in functional trait values among populations and/or population groups. Second, all 

subsets multiple regression and Bayesian information criteria will be used to determine the most 

parsimonious set of climate variables for explaining trait variation across individuals, populations, 

and species. Climate variables will include the standard 19 bioclimatic variables used in 

macroecology research (Hijmans et al. 2005), and, when sufficient extent is available, 

complementary variables from PRISM or Climate WNA will be analyzed.
GENETICS AND CLIMATE CHANGE

65

Table 1. Functional traits to be measured in the controlled-environment container experiment.

Organ Functional trait Relevance References

Whole Root-to-shoot ratio Competition, grazing tolerance Monk 1966

plant Height Light competition Westoby 1998

Lateral spread Space competition, clonality Navas and Moreau-Richard 2005

Leaf Specific leaf area Photosynthetic capacity, heat 

tolerance Wright et al. 2004

Leaf dry matter Water use efficiency Butterfield and Briggs 2011

Leaf size Aridity tolerance Niklas 1994

Stem Stem density Frost tolerance Zanne et al. 2013

Root Specific root length Belowground competition Cornelissen et al. 2003

Root density Drought tolerance Butterfield and Suding 2013

The above results will be placed in a meta-analytic framework in order to look for general 

patterns in environmental control of functional trait variation. Effect sizes will be calculated for 

both genetic variation (scaled to the ratio of within to among population variance) of functional 

traits and its environmental predictors. Consistent effect sizes across species will be used to 

identify traits and associated environmental variables to target for measurements on additional 

species in the field, to guide seed selection for restoration, and to design explicit experimental 

(targeted out-planting) tests of key study conclusions.

Expected Results and Discussion

Based on our experimental work with blue grama grass (Butterfield and Wood 2015) and 

preliminary assessment of studies for the meta-analysis, we anticipate that some functional traits 

exhibit significant broad-sense heritability and that there is a strong environmental dependence to 

that heritability. We anticipate our proposed measurement of root traits will help to identify 

patterns of variation that should be highly relevant to restoration success in dryland ecosystems. 

We also expect to identify traits that will be critical in determining population establishment 

success under a combination of climatically-regulated (e.g. aridity, growing degree days, etc.) 

conditions.

The results of this research will provide the basis for experimental restorations to test the 

applicability of functional traits in predicting restoration success. If reinforced through such outplanting experiments. Our research could help guide seed increase efforts and seed zone 

guidelines to maximize population establishment, as well as to tailor seed use to specific 

ecosystem service targets, such as erosion control and forage quality.

References

Butterfield, B. J.; Briggs, J. M. 2011. Regeneration niche differentiates functional strategies of 

desert woody plant species. Oecologia 165: 477-487.
GENETICS AND CLIMATE CHANGE

66

Butterfield, B. J.; Suding, K. N. 2013. Single-trait functional indices outperform multi-trait 

indices in linking environmental gradients and ecosystem services in a complex landscape. 

Journal of Ecology 101: 9-17.

Butterfield, B. J.; Wood, T. E. 2015. Local climate and cultivation, but not ploidy, predict 

functional trait variation in Bouteloua gracilis (Poaceae). Plant Ecology 216: 1-9.

Cornelissen, J. H. C.; Lavorel, S.; Garnier, E.; et al. 2003. A handbook of protocols for 

standardized and easy measurement of plant functional traits worldwide. Australian Journal of 

Botany 51: 335-380.

Hijmans, R. J.; Cameron. S. E.; Parra, J. L.; Jones, P. G.; Jarvis, A. 2005. Very high resolution 

interpolated climate surfaces for global land areas. International Journal of Climatology 25: 

1965-1978.

Kilkenny, F. 2015. Genecological approaches to predicting the effects of climate change on plant 

populations. Natural Areas Journal 35: 152-164.

Lavorel, S; Garnier, E. 2002. Predicting changes in community composition and ecosystem 

functioning from plant traits: revisiting the Holy Grail. Functional Ecology 16: 545-556.

Monk, C. D. 1966. Ecological importance of root/shoot ratios. Bulletin of the Torrey Botanical 

Club 93: 402-406.

Navas, M. L.; Moreau-Richard, J. 2005. Can traits predict the competitive response of 

herbaceous Mediterranean species? Acta Oecologica 27: 107-114.

Niklas, K. J. 1994. Plant allometry: the scaling of form and process. The University of Chicago 

Press: Chicago, IL. 412 p.

Pérez-Harguindeguy, N.; Diaz, S.; Garnier, E; et al. 2013. New handbook for standardized 

measurement of plant functional traits worldwide. Australian Journal of Botany 61: 167-234.

Swenson, N. G.; Enquist, B. J.; Pither, J; et al. 2011. The biogeography and filtering of woody 

plant functional diversity in North and South America. Global Ecology and Biogeography 21: 

798-808.

Westoby, M. 1998. A leaf-height-seed (LHS) plant ecology strategy scheme. Plant and Soil 199: 

213-227.

Wright, I. J.; Reich, P. B.; Westoby, M.; et al. 2004. The worldwide leaf economics spectrum. 

Nature 428: 821-827.

Zanne, A. E.; Tank, D. C.; Cornwell, W. K.; et al. 2013. Three keys to the radiation of 

angiosperms into freezing environments. Nature 506: 89-92.
GENETICS AND CLIMATE CHANGE

67

Project Title Climate Change Effects on Native Plant Establishment 

and Annual Grass Invasion: Implications for Restoration

Project Agreement No. 15-IA-11221632-202

Principal Investigators and Contact Information

Beth A. Newingham, Research Ecologist

U.S. Department of Agriculture

Agricultural Research Service

920 Valley Road

Reno, NV 89512

775.784.6057 ext. 233, Fax 775.784.1212

Beth.newingham@ars.usda.gov

Keirith Snyder, Research Ecologist

U.S. Department of Agriculture

Agricultural Research Service

920 Valley Road, Reno, NV 89512

775.784.6057 ext. 245, Fax 775.784.1212

keirith.snyder@ars.usda.gov

Project Description

Introduction

Predicted climate changes in the Great Basin include increased temperature and altered 

precipitation, which are likely to increase wildfire and annual invasive grasses (Abatzaglou and 

Kolden 2011). Although research exists on the effects of elevated CO2 on Bromus tectorum

(Ziska et al. 2005) and Bromus rubens (Smith et al. 2000, Nagel et al. 2004), little is known 

about how warming or drought may affect either invasive grass. Bromus rubens has been found 

to be as cold tolerant as Bromus tectorum but does not survive rapid temperature drops (Bykova 

and Sage 2012). Considering that Bromus rubens is currently dominant in warm deserts and 

sensitive to drastic temperature drops, increased temperatures in the Great Basin cold desert, may 

result in further invasion. When growing individually, preliminary results found that drought and 

warming reduced Bromus tectorum emergence, specific leaf area, and biomass to a greater extent 

than Elymus elymoides (Newingham et al. 2015); however, we do not know how this will affect 

plant competition.

Variable effects of altered climate may result in shifts in competitive abilities between native and 

invasive species. Previous studies have explored native species that may be resistant to invasion 

by Bromus tectorum (Leger 2008, Uselman et al. in review) and Bromus rubens (Abella et al. 

2012). These studies suggest that early seral natives (Poa and Elymus grasses for B. tectorum and 

early seral forbs for Bromus rubens) may be effective competitors. However, little is known 

about how these native species may perform under altered climate. Additionally, there have been 

no studies examining the potential competitiveness of Vulpia octoflora, which is an early season, 

annual native, with B. tectorum. Although there are limited studies on competitive interactions 
GENETICS AND CLIMATE CHANGE

68

between Vulpia octoflora and Bromus rubens, a few studies evaluated the effects of elevated 

CO2 (Nagel et al. 2004) and altered resource conditions (DeFalco et al. 2003) on these two 

species. No studies have been conducted on the effects of precipitation and temperature on 

Vulpia octoflora – Bromus rubens or Vulpia octoflora – Bromus tectorum interactions to our 

knowledge.

Objectives

In a field experiment, we will:

 Determine the effects of warming and drought on invasive and native plant emergence, 

growth, and reproduction.

 Investigate what native species mixtures may compete with Bromus tectorum or Bromus

rubens in future climate.

Methods

In a field experiment, we will examine the effects of increased temperature and altered 

precipitation on native and invasive plant growth, reproduction, and community dynamics. In 

field plots, we will establish three-3 x 3 m plots with the following four treatments: control, 

warming, drought, and warming + drought (12 plots total). Passive warming chambers will be 

constructed to increase soil temperatures approximately 5° C. Rainout shelters will be 

constructed to reduce precipitation by 50%.

We will plant eight different seed treatments into 15x15cm plots underneath each 

chamber/shelter; each treatment will have two subplots for a total of 16 plots in each 

chamber/shelter. We will use native species that occur at the Wyoming big sagebrush/mountain 

big sagebrush ecotone. Seed will be obtained from the BLM, commercial growers (such as 

Benson Farms), and/or the Malheur Experiment Station. We will attempt to obtain species from 

similar seed zones to the greatest extent possible and avoid cultivars. Native species include: 1) 

native perennial grasses (Poa secunda; POSE / Elymus elymoides; ELEL5), and 2) native annual 

grass (Vulpia octoflora; VUOC), and forbs (Achillea millefolium; ACMI2/ Machaeranthera 

canescens; MACA2). Native species will be planted with either of two invasive annual grasses: 

Bromus tectorum (BRTE) or Bromus rubens (BRRU2). Poa secunda and Elymus elymoides were 

chosen due to their competitive ability with Bromus tectorum. Vulpia octoflora is in a similar 

functional group to the invasive Bromus species, and the two forbs are adequately produced plant 

materials that are both competitive with Bromus.

Seeding treatments will include the following: 1) POSE-forbs-BRTE, 2) ELEL5-forbs-BRTE, 3) 

VUOC-forbs-BRTE, 4) POSE-forbs- BRRU2, 5) ELEL5-forbs- BRRU2, 6) VUOC-forbsBRRU2, 7) BRTE alone, and 8) BRRU2 alone. Species mixtures will be planted in grids to track 

individual plants and randomized within subplot and plot. For each species, we will measure 

plant emergence, height, specific leaf area, biomass, reproduction, δ13C, δ15N, and C:N. Results 

will be analyzed in ANOVAs; dependent variables will include temperature and precipitation as 

fixed factors.

Expected Results and Discussion

We have commenced site selection, which has included a common garden area on the University 

of Nevada, Reno campus and various locations on Bureau of Land Management land. Site 

selection will continue until an appropriate site is found; shelter construction and obtaining seed 

will begin in the spring. Our study will: 1) increase our understanding of the basic biology and 
GENETICS AND CLIMATE CHANGE

69

ecology of several native species, 2) determine native plant sensitivity to altered climate, 3) 

provide recommendations on native plant material selections under future climate, and 4) offer 

insight into the resilience of native plant communities to climate change and resistance to 

invasion. 

Additional Products

 Additional project funds were obtained for a technician through the USDAAgricultural Research CRIS project.

References

Abatzoglou, J. T.; Kolden, C. A. 2011. Climate change in western U.S. deserts: potential for 

increased wildfire and invasive annual grasses. Rangeland Ecology & Management 64: 471-478.

Abella, S. R.; Craig, D. J.; Smith, S. D.; Newton, A. C. 2012. Identifying native vegetation for 

reducing exotic species during the restoration of desert ecosystems. Restoration Ecology 20: 

781-787.

Bykova, O.; Sage, R. F. 2012. Winter cold tolerance and the geographic range separation of 

Bromus tectorum and Bromus rubens, two severe invasive species in North America. Global 

Change Biology 18: 3654–3663.

DeFalco, L. A.; Bryla, D. R.; Smith-Longozo, V.; Nowak, R. S. 2003. Are Mojave Desert annual 

species equal? Resource acquisition and allocation for the invasive grass Bromus madritensis

subsp. rubens (Poaceae) and two native species. American Journal of Botany 90: 1045-1053.

Leger, E. A. 2008. The adaptive value of remnant native plants in invaded communities: an 

example from the great basin. Ecological Applications 18: 1226-1235.

Nagel, J. M.; Huxman, T. E.; Griffin, K. L.; Smith, S. D. 2004. CO2 enrichment reduces the 

energetic cost of biomass construction in an invasive desert grass. Ecology 85: 100-106.

Newingham, B. A.; Suazo, A. A.; Germino, M. J. 2015. Bromus tectorum and native grass 

establishment under drought and warming in sagebrush steppe after fire. Great Basin Consortium 

Meeting; 2015 February 17-19; Boise, ID.

Smith, S. D.; Huxman, T. E.; Zitzer, S. F.; Charlet, T. N.; Housman, D. C.; Coleman, J. S.; 

Fenstermaker, L. K.; Seemann, J. R.; Nowak, R. S. 2000. Elevated CO2 increases productivity 

and invasive species success in an arid ecosystem. Nature 408: 79-82.

Uselman, S. M.; Snyder, K. A.; Leger, E. A.; Duke, S. E. [Submitted]. Emergence and early 

survival of early vs. late seral species in Great Basin restoration in two different soil types. 

Applied Vegetation Science. (In review).

Ziska, L. H.; Reeves, J. B.; Blank, B. 2005. The impact of recent increases in atmospheric CO2

on biomass production and vegetative retention of cheatgrass (Bromus tectorum): implications 

for fire disturbance. Global Change Biology 11: 1325-1332.
GENETICS AND CLIMATE CHANGE

70

Project Title Evaluation of Local Adaptation in Achnatherum 

hymenoides and Artemisia spp.: Implications for 

Restoration in a Changing Regional Climate

Project Agreement No. 15-IA-11221632-178

Principal Investigators and Contact Information

Lesley DeFalco, Research Plant Ecologist

U.S. Geological Survey

160 N. Stephanie St.

Henderson, NV 89074

702.564.4507, Fax 702.564.4600

ldefalco@usgs.gov

Daniel Shryock, Plant Ecologist

U.S. Geological Survey

160 N. Stephanie St.

Henderson, NV 89074

702.564.4500, Fax 702.564.4600

dshryock@usgs.gov

Todd Esque, Research Ecologist

U.S. Geological Survey 

160 N. Stephanie St.

Henderson, NV 89074

702.564.4506, Fax 702.564.4600

tesque@usgs.gov

Project Description

Introduction

Climate change and novel disturbances have the potential to alter distributions and population 

trajectories of plant species worldwide (Walther et al. 2002, Parmesan 2006). Impacts may be 

especially pronounced in arid regions where high rates of climate change are expected (Brown et 

al. 1997, Weiss and Overpeck 2005, Loarie et al. 2009). The Great Basin is predicted to 

experience increased temperatures and aridity (IPCC 2015), and recent vegetation die-offs 

suggest that plant populations may indeed be vulnerable to such changes (Breshears et al. 2005,

Miriti et al. 2007). It is also increasingly apparent that climate change effects will be expressed at 

the subspecies rather than the species level (Reusch and Wood 2007, Valladares et al. 2014), 

reflecting the accumulated responses of local populations to altered conditions. Local adaptation 

is widespread across plant taxa and expected to drive variability in population-level responses to 

climate change, particularly in regions where complex topography creates gradients in exposure 

intensity (Loarie et al. 2009). 
GENETICS AND CLIMATE CHANGE

71

Characterizing local adaptation in plants of the southern Great Basin is an important step towards 

increasing restoration effectiveness in a changing climate. Habitat for the greater sage-grouse 

(Centrocercus urophasianus) in the southern Great Basin ecosystem is imperiled by multiple-use 

activities – such as Solar Energy Zones, off-highway vehicle use, and mining – as well as 

wildfires fueled by invasive annual grasses. Low elevation, arid sites in the Great Basin have met 

with unsuccessful restoration efforts, particularly burned areas (Knutson et al. 2014). 

Understanding whether drier ecotypes exist that may enhance re-vegetation efforts and exhibit 

resilience in the face of climate change is important but infrequently addressed.

Common garden experiments characterize genetic differences in fitness traits arising from local 

adaptation in plant populations. However, these experiments also serve as natural laboratories for 

climate change research if populations are located in common garden environments that mimic 

predicted future conditions. This approach may identify resilient ecotypes and those with 

desirable traits, such as drought tolerance (e.g., Bansal et al. 2014), particularly when paired with 

genetic testing across environmental gradients. We adopt this approach by evaluating the 

performance of Great Basin populations of important restoration species in multiple Mojave 

Desert common gardens of increasing aridity relative to the Great Basin. These experiments will 

develop management guidelines for selecting Great Basin ecotypes suitable for restoration of 

arid sites in transition to warmer, drier conditions. 

Objectives

The project will support tissue and seed collections for two Great Basin taxa that are used in 

restoration and are important for wildlife habitat (Connelly et al. 2000, 2011), particularly in the 

southern Great Basin: Indian ricegrass (Achnatherum hymenoides) and sagebrush (Artemisia 

nova and/or A. tridentata). Great Basin populations of these species will be sampled and placed 

in common garden experiments located in the arid Mojave Desert, mimicking potential future 

climates. 

The sample design will incorporate Great Basin populations from a gradient of representative 

climate zones – from least to most arid - and will explicitly consider climate change predictions 

to evaluate at-risk populations. To do so, we will classify the southern Great Basin into 

contrasting climate zones. Each zone will be ranked according to its predicted velocity of climate 

change (sensu Loarie et al. 2009; Hamann et al. 2015). Plant populations will then be selected 

from leading- and trailing-edge areas (high and low climate change velocity, respectively) in up 

to three climate zones. Our experimental design addresses three key questions: 

(1) Do populations exhibit genetic differentiation in performance traits, leading to 

differential resilience when transplanted to the arid Mojave Desert? 

(2) Do climatic conditions of source populations consistently predict performance 

across common gardens of increasing aridity, such that management guidelines 

can be developed?

(3) Which source populations are most and least resilient to increased aridity, and 

which possess desirable traits for restoration?

Methods

Sample Design

Potential locations supporting ricegrass populations within the southern Great Basin were derived 

from the SEInet and Calflora herbaria networks (http://swbiodiversity.org, 
GENETICS AND CLIMATE CHANGE

72

http://ucjeps.berkeley.edu/consortium/; Figure 

1). The southern Great Basin ecoregion 

(defined as the EPA’s “Central Basin and 

Range” ecoregion) was delineated into six 

climate zones based on 11 precipitation and 

temperature variables. Climate layers were 

derived at a 2 km2scale using the program 

ClimateWNA (Wang et al. 2012). Six climate 

zones were then identified using partitioningaround-medoids (r package “cluster”), a robust 

form of k-means clustering (Figure 2). Each of 

the zones were ranked according to two 

criteria: (1) average ecological distance to 

Mojave Desert common garden sites, with 

larger distances indicating less similar climate 

conditions (Figure 3); and (2) average 

predicted climate change velocity (Hamann et 

al. 2015), with higher velocities indicating 

more severe exposure to climate change 

(heightened temperatures and aridity; Figure 

4). Climate change predictions were based on a near-term (2040-2070), high-emission scenario 

(RCP8.5) for three CMIP5 models (CCSM4, GFDL-CM3, HadGEM2-ES; IPCC 2015). We 

selected three climate zones with low to moderate ecological distances to the Mojave Desert 

common gardens and with high predicted climate change velocities as suitable for sampling.

Figure 1. Potential ricegrass (ACHY) 

populations drawn from herbaria records.

Figure 2. Six climate zones in the southern 

Great Basin derived through cluster analysis 

of temperature and precipitation 

characteristics. Figure 3. Ecological distances between the 

southern Great Basin (northern polygon) and 

Mojave (southern polygon) common gardens.
GENETICS AND CLIMATE CHANGE

73

Figure 5. Leading- and trailing-edge areas within 3 climate zones from which ricegrass populations 

will be sampled. 

Figure 4. Velocity of climate change predicted 

for the southern Great Basin (Hamann et al. 

2015). 
GENETICS AND CLIMATE CHANGE

74

Greenhouse and Common Gardens

Following the sampling design described above, we will: 1) collect leaves (for genetic analysis) 

and tillers (for common gardens) from 4-6 Great Basin populations of ricegrass that will be 

combined with current Mojave collections (N~20 populations), 2) propagate ricegrass plants 

from tillers that will be transplanted into five Mojave Desert common gardens during 2016, and 

3) collect seeds of sagebrush for propagation and evaluation in three Great Basin-Mojave 

gardens during FY2016 pending funding. Ricegrass tillers will be grown in the U.S. Geological 

Survey greenhouse (Boulder City, Nevada) in 10.2 cm x 10.2 cm x 30.5 cm (4” x 4” x 12”) plant 

bands prior to transplanting.

Expected Results and Discussion

Of the six climate zones we identified (Figure 2), zones 1, 2, 6, and 5 were most similar to the 

Mojave Desert (in decreasing order) and are suitable for collections. Zones 3 and 4 were very 

dissimilar in both precipitation and temperature. In terms of climate change velocity, Zones 1, 5, 

4, and 2 had the highest predicted climate change velocities (in decreasing order).

We therefore selected Zones 1, 2, and 5 as suitable for sampling, representing a gradient of 

climatic conditions from most arid to cooler, moister sites. Within each zone, we identified both 

leading-edge (high climate change velocity) and trailing-edge (lower velocity) areas (Figure 5). 

Sampling within each climate zone will include one leading edge population and one trailing 

edge population. 

Sampled populations will be placed in up to five Mojave Desert common gardens reflecting a 

gradient of decreasing ecological similarity to their source sites (the Mojave common gardens 

include both arid and cooler / moister sites). In each common garden, we will measure 

performance traits, including growth, survival, and reproductive characteristics. This will enable 

us to develop response functions linking source population climate with predicted performance at 

proposed restoration sites. 

Expected products from this research include: (1) identification of resilient ecotypes for restoring 

arid, low-elevation sites; (2) increased understanding for how Great Basin species will respond to 

climate change at an intraspecific level; and (3) interactive, spatial planning tools for resource 

managers that display suitable seed source areas for particular restoration sites. These products 

aim to increase restoration effectiveness for arid sites in a changing climate. 

References

Bansal, S.; Harrington, C. A.; Gould, P. J.; St. Clair, J. B. 2015. Climate-related genetic variation 

in drought-resistance of Douglas-fir (Pseudotsuga menziesii). Global Change Biology 21: 947-

958. 

Breshears, D. D.; Cobb, N. S.; Rich, P. M.; Price, K. P.; Allen, C. D.; Balice, R. G.; et al. 2005. 

Regional vegetation die-off in response to global-change type drought. Proceedings of the 

National Academy of Sciences of the USA 102: 15144-15148.
GENETICS AND CLIMATE CHANGE

75

Brown, J. H.; Valone, T. J.; Curtin, C. G. 1997. Reorginization of an arid ecosystem in response 

to recent climate change. Proceedings of the National Academy of Sciences of the USA 94: 

9729-9733.

Connelly, J. W.; Schroeder, M.; Sands, A. M.; Braun, C. E. 2000. Guidelines to manage sage 

grouse populations and their habitats. Wildlife Society Bulletin 28: 967-985.

Connelly, J. W.; Rinkes, E. T.; Braun, C. E. 2011. Characteristics of greater sage-grouse habitats: 

a landscape species at micro- and macroscales. In: Knick, S. T.; Connelly, J. W., eds. Greater 

sage-grouse: Ecology and Conservation of a landscape species and its habitats. Studies in Avian 

Biology, 38. University of California Press, Berkeley, CA: Cooper Ornithological Society: 

chapter 4.

Hamann, A.; Roberts, D. R.; Barber, Q. E.; Carroll, C.; Nielsen, S. E. 2014. Velocity of climate 

change algorithms for guiding conservation and management. Global Change Biology 21: 997–

1004.

IPCC [Intergovernmental Panel on Climate Change]. 2013. Climate change 2013: the physical 

science basis. Contribution of Working Group I to the Fifth Assessment Report of the 

Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge. 

Knutson, K. C.; Pyke, D. A.; Wirth, T. A.; Arkle, R. S.; Pilliod, D. S.; Brooks, M. L.; Chambers, 

J. C.; Grace, J. B. 2014. Long-term effects of seeding after wildfire on vegetation in Great Basin 

shrubland ecosystems. Journal of Applied Ecology 51: 1414-1424.

Loarie, S. R.; Duffy, P. B.; Hamilton, H.; Asner, G. P.; Field, C. B.; Ackerly, D. D. 2009. The 

velocity of climate change. Nature 462: 1052–1055.

Miriti, M. N.; Rodríguez-Buriticá, S.; Wright, S. J.; Howe, H. F. 2007. Episodic death across 

species of desert shrubs. Ecology 88: 32-36.

Parmesan, C. 2006. Ecological and evolutionary responses to recent climate change. Annual 

Review of Ecology, Evolution, and Systematics 37: 637-669.

Reusch, T. B. H.; Wood, T. E. 2007. Molecular ecology of global change. Molecular Ecology 

16: 3973-3992.

Valladares, F.; Matesanz, S.; Guilhaumon, F.; Araujo, M. B.; Balaguer, L.; Benito-Garzon, M.; 

Cornwell, W.; et al. 2014. The effects of phenotypic plasticity and local adaptation on forecasts 

of species range shifts under climate change. Ecology Letters 17: 1351-1364.

Wang, T.; Hamann, A.; Spittlehouse, D. L.; Murdock, T. 2012. ClimateWNA – high-resolution 

spatial climate data for Western North America. Journal of Applied Meteorology and 

Climatology 51: 16-29.

Walther, G. R.; Post, E.; Convey, P.; Menzel, A.; Parmesan, C.; Beebee, T. J. C.; et al. 2002. 

Ecological responses to recent climate change. Nature 416: 389-395.
GENETICS AND CLIMATE CHANGE

76

Weiss, J. L.; Overpeck, J. T. 2005. Is the Sonoran Desert losing its cool? Global Change Biology 

11: 2065-2077.
77

PLANT MATERIALS AND

CULTURAL PRATICES
PLANT MATERIALS AND CULTURAL PRACTICES

78

Project Title Smoke-Induced Germination of Great Basin Native 

Forbs

Project Agreement No. 11-CR-11221632-005

Principal Investigators and Contact Information 

Robert Cox, Associate Professor

Texas Tech University 

Box 42125 

Lubbock, TX 79409

806.742.2841, Fax 806.742.2280

robert.cox@ttu.edu 

Project Description

Introduction

Smoke-induced germination of native seeds has been described in several ecosystems, but little 

is known about whether smoke may influence the germination of species native to the Great 

Basin. However, an understanding of smoke-induced germination has the potential to increase 

the success of restoration and revegetation seedings.

Smoke-induced germination has been relatively well studied for certain ecosystems, including 

areas in California, South Africa, and Australia (Keeley and Fotheringham 2000). Species in 

these areas respond to smoke because it represents a cue that fire has prepared a suitable site for 

new growth (Crosti et al. 2006). The ability of smoke to enhance the germination of native 

species has also been suggested as a way to increase the density, diversity, and success of native 

seedings (Roche et al. 1997). 

There are several reasons for suspecting that species native to the Great Basin might respond to 

smoke. First, the climate of the Great Basin is similar to the Mediterranean climates where 

smoke-induced germination has been observed. Second, periodic fires are prominent in each of 

these regions. Third, many of the native forbs in the Great Basin belong to genera that are known 

for having smoke responses, including Astragalus, Cryptantha, Erigeron, Penstemon, Phacelia, 

Salvia, and others.

In order to investigate the possibility of smoke response in Great Basin species, we first 

conducted a wide screening through as many species as possible. We asked Great Basin Native 

Plant Project (GBNPP) collaborators for small lots (approximately 500-1000 seeds) of as many 

species as were available. From each seedlot, we took a random sample of 400 seeds, and 

divided those into sublots of 25 seeds each. Four replicates of each sublot (for a total of 100 

seeds) were to be soaked in one of three different concentrations of smoke-water, plus a control 

distilled water only. Smoke-water was purchased from Regen 2000TM, which is derived from 

commercial food flavoring products (see Baldwin et al. 1994). Smoke water concentrations were 

1:10, 1:100, 1:1000. After soaking, seeds were germinated according to established protocol (i.e. 

AOSA or ISTA).
PLANT MATERIALS AND CULTURAL PRACTICES

79

Objectives

The objective of this study was to test species native to the Great Basin for germination response 

to smoke. We hypothesize that some species may be responsive, as other shrub-dominated 

ecosystems also display frequent responsiveness. Responsive species could be useful for 

management of imperiled Great Basin sagebrush ecosystems. 

Methods

Each species was tested for smoke response at 4 levels of smoke dilution with distilled water: 1:0 

(the control of no smoke, just distilled water), 1:10, 1:100, 1:1000. This was done by creating a 

volume of each smoke dilution beforehand, which was then stored in laboratory containers for 

use in the tests. Species were tested for response to smoke both without pretreatments, as we 

were interested in determining whether smoke exposure could ameliorate the need for 

pretreatments. For each tested species we: 1) counted out the required numbers of seeds, and 

placed them in manila coin envelopes until ready to treat and test. Each species was counted into 

packs of 25 seeds each. When the smoke test was ready, we placed each group of 25 seeds into 

separate beakers, and added enough of the proper dilution to each beaker to cover the seeds with 

ample fluid. Seeds were soaked for 20 hours, after which the smoke solution was drained from 

the seeds, and each separate group of 25 seeds were placed into a separate germination boxes 

(lined with 2 layers of germination paper). 

Germination papers were moistened until they were at capacity. Each box was placed into the 

germination chamber programmed with the proper temperature and light/dark cycles. The boxes 

were stacked in groups, and an empty box (no seeds but with germination papers) was placed on 

top of each stack to ensure all boxes have the same light environment. Each box was observed to 

record germinating seedlings. When a seed 

was observed to have germinated, it was 

recorded and removed from the box. 

Germination was considered to have 

occurred when at least 1mm of radicle (root) 

could be seen on the outside of the seed coat. 

Observations were continued until no 

germination was observed for 1 week. Final 

germination totals were tallied, and data were 

analyzed via JMPTM to determine treatment 

effects. Species were analyzed separately, 

with treatment (smoke dilution) as the 

independent variable, and total germination 

as the dependent variable.

Results and Discussion

We tested 19 species, including grasses, 

forbs, and shrubs, for smoke response. 

Grasses tested were: Achnatherum 

Figure 1. Germination of Agoseris glauca under 

different levels of smoke exposure. Error bars 

represent standard error. Germination was 

significantly less under the 1:10 level of smoke 

exposure.
PLANT MATERIALS AND CULTURAL PRACTICES

80

hymenoides, Achnatherum thuberianum, Poa secunda, and Pseudoroegneria spicata. Forbs tested 

included: Achillea millefolium, Agoseris glauca, Balsamorhiza hookeri, Balsamorhiza saggittata, 

Lomatium dissectum, Lomatium grayi, Penstemon speciosus, and Phacelia hastata. Shrubs tested 

were: Artemisia tridentata, Atriplex canescens, Chrysothamnus nauseosus, Erigeron pumilus, 

Eriogonum heracleoides, Eriogonum umbellatum, and Grayia spinosa.

Overall, we found that seven species responded to smoke by increasing or decreasing total 

germination percent. Responding species were: Agoseris glauca, Artemisia tridentata, Atriplex 

canescens, Eriogonum heracleoides, Eriogonum umbellatum, Poa secunda, and Pseudoroegneria 

spicata. Species that did not display a germination response to smoke were: Achillea millefolium, 

Achnatherum hymenoides, Achnatherum thurberianum, Balsamorhiza hookeri, Balsamorhiza 

sagitatta, Chrysothamnus nauseosus, Erigeron pumilus, Grayia spinosa, Lomatium dissectum, 

Lomatium grayi, Penstemon speciosus, and Phacelia hastata. 

Agoseris glauca (Figure 1) experienced significantly less germination when exposed to high 

(1:10) levels of smoke. Germination at other exposure levels did not differ from each other, or 

from the control. Germination of Artemisia tridentata (Figure 2) was also significantly lower at 

high (1:10) smoke exposure, while other levels did not differ. Atriplex canescens displayed 

greater germination at very low levels of smoke exposure (1:1000) than the control, but not the 

1:10 level (Figure 3). Other levels did not differ from each other. Germination of Eriogonum 

heracleoides was less at high smoke exposure (1:10) than all other levels of smoke exposure, and 

germination at other levels did not differ (Figure 4). Eriogonum umbellatum displayed less 

germination at the 1:10 level of smoke exposure than the control, while the 1:100 level also did 

not differ from the 1:10 level (Figure 5). Germination of Poa secunda, was different only 

between the 1:1000 and the 1:100 levels; no level was different from the control. Finally, 

germination of Pseudoroegneria spicata was significantly less at moderate smoke exposure 

(1:100) as compared to the control.

Figure 3. Germination of Artemisia tridentata

under different levels of smoke exposure. Error 

bars represent standard error. Germination was 

significantly greater than the control at the 

1:1000 level of smoke exposure. The 1:10 level 

did not differ from either the control or the 

1:1000.

Figure 2. Germination of Artemisia tridentata

under different levels of smoke exposure. Error 

bars represent standard error. Germination was 

significantly less under the 1:10 level of smoke 

exposure.
PLANT MATERIALS AND CULTURAL PRACTICES

81

Management Applications and/or Seed Production Guidelines

It is apparent that smoke exposure has an effect on a wide variety of species native to the Great 

Basin. We found smoke response in a grass, Pseudoroegneria spicata, which appeared to be 

modestly promoted by moderate (i.e. 1:100) levels of smoke exposure. This effect is not well 

studied for grasses as a group and bears further study. We also found one forb (Agoseris glauca), 

and four shrubs (Artemisia tridentata, Atriplex canescens, Eriogonum heracleoides, and 

Eriogonum umbellatum) that responded. Germination of all appeared to be inhibited by smoke 

exposure.

Though smoke-stimulated germination, resulting in higher germination rates or faster 

germination times are perhaps more famous, smoke is also known to inhibit germination of some 

species, and this effect appears to predominate in the species tested from the Great Basin. This 

finding offers a note of caution then for adopting smoke treatments, including methods such as 

smoke-infused water (as used in this study), ash, or charcoal, as restoration or revegetation aids 

in the Great Basin.

References.

Baldwin, I. T.; Staszak-Kozinski, L.; Davidson, R. 1994. Up in smoke: I. Smoke-derived 

germination cues for postfire annual, Nicotiana attenuata torr. Ex. Watson. Journal of Chemical 

Ecology 20: 2345-2371.

Figure 4. Germination of Eriogonum 

heracleoides under different levels of smoke 

exposure. Error bars represent standard error. 

Germination was significantly less than all 

other treatments at the 1:10 level of smoke 

exposure. 

Figure 5. Germination of Eriogonum 

umbellatum under different levels of smoke 

exposure. Error bars represent standard error. 

Germination was significantly less than the 

control at the 1:10 level of smoke exposure. 

Germination at the 1:100 level of exposure 

also did not differ from the 1:10 level.
PLANT MATERIALS AND CULTURAL PRACTICES

82

Crosti, R.; Ladd, P. G.; Dixon, K. W.; Piotto, B. 2006. Post-fire germination: the effect of smoke 

on seeds of selected species from the central Mediterranean basin. Forest Ecology and 

Management 221: 306-312.

Keeley, J. E.; Fotheringham, C. J. 2000. Role of fire in regeneration from seed. In: Fenner, M., 

ed. Seeds, the ecology of regeneration in plant communities. 2nd edition. Wallingford, UK, 

CABI Publishing: 311-330

Roche, S.; Koch, J. M.; Dixon, K. W. 1997. Smoke enhanced seed germination for mine 

rehabilitation in the southwest of Western Australia. Restoration Ecology 5: 191–203
PLANT MATERIALS AND CULTURAL PRACTICES

83

Project Title Developing Protocols for Maximizing Establishment of 

Great Basin Legume Species

Project Agreement No. 11-IA-11221632-007

Principal Investigators and Contact Information

Douglas A. Johnson, Plant Physiologist

USDA-Agricultural Research Service

Forage and Range Research Lab 

Utah State University

Logan, UT 84322-6300

435.797.3067, Fax 435.797.3075

doug.johnson@ars.usda.gov

B. Shaun Bushman, Research Geneticist

USDA-Agricultural Research Service

Forage and Range Research Lab 

Utah State University

Logan, UT 84322-6300

435.797.2901, Fax 435.797.3075

shaun.bushman@ars.usda.gov

Project Description 

Introduction

Grasses typically comprise the core of revegetation/restoration efforts in the Great Basin, and 

seed growers have been successful at producing large volumes of high quality seed for many 

grass species. Native forb species, however, have been disproportionately under-represented in 

revegetation/restoration projects in the Great Basin, both in the number of species and in the 

volume of seed available for each species. Establishing indigenous forbs during revegetation/ 

restoration is central to achieving diverse systems that function sustainably and resist invasion of 

exotic weeds. As a result, there is a need to identify forbs from western North America that are 

adapted to low precipitation zones and amenable to field seed production so that these species 

can be more fully utilized in revegetation/restoration efforts. 

Previous research has identified western prairie clover (Dalea ornata), Searls’ prairie clover 

(Dalea searlsiae), and basalt milkvetch (Astragalus filipes) as leguminous forbs that have 

potential to augment the few existing native forb species that are currently available for 

commercial use. However, additional research with these species is needed to improve their 

germination and seedling establishment in seed production fields and rangeland sites. Seeds of 

species in Fabaceae are known to have that benefit from seed scarification. In addition, prechilling treatments in combination with seed scarification may enhance field establishment in 

seed production fields and on revegetation/restoration sites. 
PLANT MATERIALS AND CULTURAL PRACTICES

84

Methods

Greenhouse Experiment 1 

The objective of Experiment 1 was to test the effects of seed scarification methods and planting 

depths. Seeds were planted into sand-filled benches (kept well-watered) with three seed 

treatments: acid scarification, mechanical scarification, and untreated control. Fifty seeds were 

planted for each of five entries (Majestic and Spectrum western prairie clover, Fanny and 

Bonneville Searls’ prairie clover, and NBR-1 basalt milkvetch) at a depth of either 6 mm (0.25 

inch) or 19 mm (0.75 inch). The study used four replications in a randomized complete block 

design. Numbers of emerged seedlings were counted three times a week for the duration of the 

experiment. Total emergence (TEM) was determined as the number of seedlings that emerged by 

the end of the experiment and rate of emergence (RATE) was calculated (Maguire 1962). 

Greenhouse Experiment 2 

The purpose of Experiment 2 was to test the effects of soil composition on seedling emergence. 

Majestic western prairie clover, Bonneville Searls’ prairie clover, and NBR-1 basalt milkvetch 

were used in this experiment. Fifty seeds were planted for each species in a replicated split-plot 

design with soil compositions as whole plots and seed treatments as sub-plots. Seeds were 

planted at a 6-mm soil depth in mixtures of fine sandy loam (FSL) and silty clay loam (SCL): 

100% FSL, 33% SCL/67% FSL, 67% SCL/33% FSL, and 100% SCL, which are referred to as 

FSL (sand), 33-SCL, 67-SCL, and SCL (clay), respectively. Seed treatments within each whole 

plot included acid-scarified seed and untreated seed. 

Laboratory Experiment 3

The goal of Experiment 3 was to determine the effect of seed scarification (mechanical and no 

scarification), pre-chilling treatments, and germination substrate (blotter paper and sand) on 

germination in NBR-1 basalt milkvetch and Spectrum western prairie clover. Seed was 

mechanically scarified with sandpaper or left unscarified. Plastic germination boxes of seeds 

were either pre-chilled in the dark at 5o C for 3 weeks prior to the 10-week germination period or 

not pre-chilled. After pre-chilling, germination boxes were kept in a laboratory maintained at 

about 22o C under ambient daylight conditions. Six germination boxes were used for each 

combination of treatments. Boxes were randomized across all combinations of seed treatments 

before the beginning of the germination period, and then randomized again after each weekly 

germination count during a 10-week period. 

Field Experiment

Seeds of NBR-1 basalt milkvetch were subjected to five treatments: 1) untreated control, 2) 

mechanical scarification, 3) immersion in boiling water for 10 seconds, 4) scarification with 97% 

sulfuric acid for 5 minutes, and 5) acid scarification followed by a 14-day pre-chill (4oC) in the 

dark after blending into moist sand (250 mg sand + 60 ml tap water). Seeds of the five treatments 

were planted on 16 April 2014 with a Wintersteiger seeder at a rate of 494 seeds in single-row, 

5 m long plots at two locations in northern Utah (Millville and North Park). At both locations, 

the five treatments were arranged in a randomized complete block design with six replications. 

Numbers of emerged seedlings were counted periodically through the growing season. 

Results

Greenhouse Experiment 1

For total emergence (TEM), the main effects of seed treatment, entry, and planting depth were 

significant along with the entry×treatment and entry×planting depth interactions. The 
PLANT MATERIALS AND CULTURAL PRACTICES

85

treatment×planting depth and the three-way interaction were not significant. For rate of 

emergence (RATE), the three main effects and all two-way interactions were significant, but the 

three-way interaction was not significant. Both acid and mechanical scarification methods 

resulted in significantly and substantially higher TEM than untreated seeds, and the two seed 

scarification methods differed significantly from each other for TEM across all entries (Fig. 1A). 

Majestic and Spectrum western prairie clovers had similar TEM values, with acid scarification 

resulting in significantly higher TEM than mechanical scarification (Fig. 1A). For Searls’ prairie 

clover, Bonneville had higher TEM for acid compared to mechanical scarification, but for Fanny 

mechanical scarification had a slightly higher TEM than acid scarification. The TEM of NBR-1 

basalt milkvetch was higher with mechanical compared to acid scarification, but only improved 

from four emerged seedlings in the untreated seed compared to 16 emerged seedlings in the 

mechanically scarified seed (Fig. 1A). 

Figure 1. Total emergence (TEM) and rate of emergence (RATE) for western prairie clover (Do_Maj, 

Majestic; Do-Spec, Spectrum), Searls’ prairie clover (Ds-26 = Fanny, Ds-23 = Bonneville), and basalt 

milkvetch (Af_NBR-1) entries in Greenhouse Experiment 1. (A) TEM and (B) RATE of entries for 

seed that was acid-scarified (acid), mechanically scarified (mech), or untreated (ut). (C) TEM and (D) 

RATE of entries planted at 6- or 19-mm planting depths. Bars with different letters on top are 

significantly different at p < 0.05 significance level (Bushman et al. 2015).

For RATE, acid scarification also led to the most rapid emergence in the four prairie clover 

entries, followed by mechanical scarification and untreated seed (Fig. 1B). Majestic, Spectrum, 

and Bonneville Searls’ prairie clover exhibited similar patterns of response for the three seed 
PLANT MATERIALS AND CULTURAL PRACTICES

86

treatments, with acid scarification resulting in a higher (faster) RATE than mechanical 

scarification. Fanny Searls’ prairie clover showed a trend of improvement in RATE for acid 

compared to mechanically scarified seeds. RATE was substantially lower (slower) for NBR-1 

compared to the prairie clover entries, and NBR-1 had a trend of higher RATE for mechanically 

scarified compared to acid-scarified seed (Fig. 1B). Deeper planting depth did not have a 

significant effect on the TEM of Majestic, Spectrum, and Bonneville prairie clovers, but it 

reduced the TEM of Ds-26 from 90% to 74% seedlings and the TEM of NBR-1 from 28% to 

20% seedlings (Fig. 1C). The deeper planting depth did result in significant reductions in RATE 

for all four prairie clover entries when planted at 19 mm compared to 6 mm (Fig. 1D). RATE 

values for NBR-1 were low, and the deeper depth did not result in a significant delay in 

emergence. 

Greenhouse Experiment 2

Using the Majestic western prairie clover, Bonneville Searls’ prairie clover, and NBR-1 basalt 

milkvetch, seed treatment and entry were tested along with soil composition. For both TEM and 

RATE, significant effect (p < 0.0001) were observed for seed treatment and entry. Soil 

composition was significant for TEM but not for RATE. For both TEM and RATE, 

treatment×entry and entry×soil composition interaction effects were significant. The significant 

entry×soil composition interaction and the significant three-way interactions for both TEM and 

RATE were most likely due to the varying responses of NBR-1 compared to the prairie clover 

species (Fig. 2). 

Similar to Experiment 1, scarified seeds had significantly higher TEM values than untreated 

seeds for all three entries (Fig. 2A). TEM of scarified Majestic seeds was 70-82% compared to 8-

12% for untreated seeds, scarified Bonneville was 60-83% compared to 2-4% for untreated seed, 

and scarified NBR-1 was 15-18% compared to 2-6% for untreated seeds. The four soil 

compositions used in Experiment 2 ranged from a FSL (sandy) composition to SCL (high clay) 

composition. Scarified seeds of Majestic and Bonneville prairie clovers exhibited significant 

decreases in TEM as the clay content in soils increased while untreated seeds of Majestic and 

Ds-23 showed little or no responses to soil composition (Fig. 2A). NBR-1 varied from the two 

prairie clover responses with an overall lower TEM, and an increased TEM in soils containing 

clay compared to FSL (sandy). 

RATE exhibited a similar pattern of responses as those for TEM, with scarified seeds of all three 

entries emerging more rapidly than untreated seeds (Fig. 2B). For scarified Majestic and 

Bonneville, RATE was faster in FSL (sandy) soils compared to soils with higher clay content. 

Untreated Majestic and Bonneville exhibited a low (slow) RATE, but no significant differences 

as clay content increased. For NBR-1 basalt milkvetch, scarified and untreated seeds of NBR-1 

showed a significant increase in RATE with higher clay content (Fig. 2B). 

Laboratory Experiment

The number of germinated seeds of basalt milkvetch and western prairie clover increased 

linearly through time for all treatment combinations. The two species, however, differed in their 

germination responses with western prairie clover having a less complex germination pattern 

than basalt milkvetch. Scarification increased germination in western prairie clover (p < 0.0001) 

from 15.4 ± 0.4% without scarification to 29.4 ± 0.4% with scarification. However, neither prechilling nor substrate had significant (p > 0.05) effects on western prairie clover. The benefit of 

scarification increased across the 10-week course of germination. Despite the lack of a 
PLANT MATERIALS AND CULTURAL PRACTICES

87

significant pre-chilling main effect on germination in western prairie clover, pre-chilling 

increased cumulative germination as the trial progressed. 

Scarification increased germination (p < 0.0001), though the effect was smaller for basalt 

milkvetch than for western prairie clover, increasing from 9.4 ± 0.4% to 19.5 ± 0.5%. The effect 

of pre-chilling was greater than that for scarification in basalt milkvetch, increasing germination 

from 7.8 ± 0.3% to 22.0 ± 0.5%. Basalt milkvetch germination was also greater (p < 0.0001) 

when sand was used as a substrate (averaging 18.5 ± 0.5%) compared to blotter paper (10.2 ± 

0.4%). Suppression of germination by blotter paper was minimal at the first-week count, but 

blotter paper hindered germination during later weeks. The effects of pre-chilling and 

scarification interacted (p < 0.01) and were synergistic (Fig. 3), i.e., pre-chilling increased 

germination of scarified seed (averaging 18.7 ± 0.4%) more than unscarified seed (10.3 ± 0.4%). 

Pre-chilling interacted with substrate (p < 0.01), as the lack of pre-chilling was less of a 

disadvantage on sand than on blotter paper, an effect that became more pronounced through time 

(Fig. 3). Though the pre-chilling×scarification and pre-chilling×substrate interactions were 

significant (p < 0.01), they were much smaller in magnitude than the main effects of 

scarification, pre-chilling, and substrate. Neither the scarification× substrate interaction nor the 

pre-chilling× scarification× substrate interaction were significant (p > 0.10). In summary, 

germination of the pre-chilled/scarified/sand treatment combination was numerically highest at 

all 10 weeks (42.3 ± 1.6% at week 10), while the non-chilled/unscarified/blotter paper treatment 

combination was always the lowest (3.0 ± 0.5% at week 10).

Field Experiment

Differences between basalt milkvetch seed treatments for seedling density were dramatic at both 

North Park and Millville (Fig. 4). At North Park, means (± S.E.) for acid seed treatment (6.3 ± 

2.2 seedlings per row) and boiling seed treatment (6.6 ± 2.3) were not significantly different (p > 

0.05) from the untreated control (2.5 ± 1.4). Results were similar at Millville with the acid 

treatment (5.6 ± 1.7) and boiling treatment (4.0 ± 1.4) being similar to the control treatment (1.9 

± 0.9) (p > 0.05). However, the acid + pre-chilling and sandpaper treatments were more effective 

(p < 0.01) than the control treatment at both North Park (36.7 ± 6.9 and 38.0 ± 7.1 vs. 2.5 ± 1.4, 

respectively) and Millville (22.9 ± 5.5 and 22.3 ± 5.4 vs. 1.9 ± 0.9, respectively). While seedling 

density for the acid, boiling, and control treatments remained stable across the evaluation period, 

we observed seedling mortality for acid + pre-chilling and sandpaper treatments at both locations 

during July and September (Fig. 4). 

Discussion

Greenhouse Experiments 1 and 2

Scarification alone increased germination of western and Searls’ prairie clover seeds to more 

than 80% (except Bonneville) while scarification did not increase germination of NBR-1 basalt 

milkvetch seed. Majestic and Spectrum western prairie clover responded in a similar manner. 

Acid scarification increased the percentage of viable seed to about 70%, increased germination to 

about 85%, increased TEM to 48 seedlings (96%) (Fig. 1A, 2A), and increased RATE more than 

eight-fold (Fig. 1B, 2B) when compared to untreated seed. Meanwhile, mechanical scarification 

increased viable seed to 34-43%, increased germination to 60-61%, increased TEM to 39 

seedlings (78%) (Fig. 1A, 2A), and increased RATE more than five-fold (Fig. 1B, 2B). Although 

acid scarification was more effective than mechanical scarification for both Majestic and 

Spectrum, both scarification methods substantially improved seedling germination and 

emergence. 
PLANT MATERIALS AND CULTURAL PRACTICES

88

Neither planting depth (Fig. 1) nor soil composition (Fig. 2) exhibited effects as large as seed 

scarification. Planting depth had no significant effect on TEM in Experiment 1, but it did slow 

RATE (Fig. 1C, 1D). This slower RATE may not necessarily reduce TEM in irrigated seed 

production fields, but under rangeland planting conditions a slower RATE could lead to lower 

TEM because of missed strategic rainfall events or preemption of limited soil water and/or 

nutrients by invasive weedy species. Soil composition changes resulted in significant effects on 

TEM and RATE, with slight reductions for both traits in clay containing soils (Fig. 2A, 2B). 

Clay content in soils can improve the ability of soils to hold water for plant use, but can also 

cause crusting that impedes seedling emergence. For Majestic, the added capacity of clay to hold 

water was apparently unnecessary, whereas the tendency of clay soils to crust likely prevented 

some seedlings from emerging. 

Untreated seed of Bonneville Searls’ prairie clover had a high proportion of viable hard seed, a 

low germination percent, and negligible TEM and RATE values (Fig. 1A, 2A). Bonneville 

responses to scarification and planting depth were very similar to those of the Majestic and 

Spectrum western prairie clover, and indicated that a similar seed germination protocol could be 

used for both species. Interestingly, the reduction in TEM and RATE in SCL (clay) soil 

compositions was more pronounced for Bonneville than Majestic western prairie clover (Fig. 2A, 

2B), and this deleterious effect of soil crusting was observed to a greater extent for seedlings of 

Bonneville, which were unable to penetrate the crust by the end of the experiment. 

Compared to Majestic and Spectrum western prairie clover, Fanny Searls’ prairie clover 

exhibited a lower viable hard percentage for untreated seeds, attenuated improvement of 

germination upon scarification, higher TEM and RATE values for untreated seed (Fig. 1A, 2A), 

and lower TEM and RATE values for scarified seed (Fig. 1A, 2A). Seed of Fanny was the only 

seed source not cleaned at the USDA-ARS Forage and Range Research Laboratory at Logan, 

UT. It underwent a more aggressive mechanical cleaning process than the other entries at the 

USDA-NRCS Plant Materials Center at Aberdeen, ID, which may have partially scarified the 

seed and led to different responses observed in this study. Despite this partial scarification of 

Fanny seed, the additional scarification imposed by our seed treatments still resulted in improved 

viability, germination, TEM, and RATE. Thus, regardless of seed cleaning method, seed 

scarification would further improve germination and emergence of prairie clover species.

 

Responses of NBR-1 basalt milkvetch in these experiments were markedly different than those 

of the two prairie clover species. NBR-1 exhibited 95% viable hard seed and 4% germination for 

untreated seed. Although scarification reduced its percentage of viable hard seed, it did not 

improve the germination percentage and seedling emergence, which remained below 20% (Fig. 

1A, 2A). Unlike the prairie clovers, NBR-1 had a higher TEM and RATE with mechanical 

compared to acid scarification (Fig. 1A, 1B), showed a reduced TEM at a 19-mm planting depth 

(Fig. 1C), and resulted in greater TEM and higher RATE in clay containing soils (Fig. 2A, 2B). 

These results highlight a uniqueness of NBR-1 seedling germination and emergence compared to 

the prairie clover species, and underscores that a different seedling establishment protocol is 

required to maximize establishment of basalt milkvetch. Because NBR-1 germinates and 

emerges at such a slow rate, it may benefit from the increased water-holding capacity that clay 

soil compositions provide and emerge at a higher percentage under rangeland planting conditions 

in clay containing soils. The slow NBR-1 emergence, however, may also result in variable and 

reduced TEM at deep or variable planting depths, which often occurs in rangeland plantings. 
PLANT MATERIALS AND CULTURAL PRACTICES

89

Laboratory Experiment and Field Experiment

Results for western prairie clover that dormancy is alleviated by scarification is consistent with 

germination being controlled by physical dormancy (i.e., hard-seededness), which is common in 

the Fabaceae and confers seed longevity. The case for physical dormancy in western prairie 

clover is also supported by a 5.4% increase in imbibition after scarification. Western prairie 

clover did not exhibit physiological dormancy, as evidenced by a lack of response to pre-chilling. 

For basalt milkvetch, both scarification and pre-chilling markedly increased germination both in 

Figure 2. (A) Total seedling emergence (TEM) or (B) rate of emergence (RATE) of western prairie clover 

(Do_Maj, Majestic), Searls’ prairie clover (Ds-23 = Bonneville), and basalt milkvetch (Af_NBR-1) entries 

for seed that was acid-scarified (acid) or untreated (ut) and planted in four soil compositions in Greenhouse 

Experiment 2. Soil compositions were 100% fine-sandy loam (FSL), 100% sandy-clay loam (SCL), 33% 

FSL / 67% SCL, and 67% FSL / 33% SCL. Bars with different letters on top are significantly different at 

p < 0.05 significance level (Busman et al. 2015).
PLANT MATERIALS AND CULTURAL PRACTICES

90

the laboratory and field (Figs. 3 and 4). Thus a combination of physical dormancy and non-deep 

physiological dormancy (i.e., combinational dormancy) appears to be involved in germination of 

basalt milkvetch. Physical dormancy usually results from impermeability of seed to water. 

Increased germination percentage and rate is an advantage for fall establishment of a seed field; 

however, for seedling establishment on rangelands, it is less clear. 

To establish seed production fields and restore rangelands with western prairie clover (Majestic 

and Spectrum) or Searls’ prairie clover (Fanny and Bonneville), seed scarification is critical. 

Planting depth differences, which are inevitable in rangeland seeding, but less so in agronomic 

seed production, indicated that a shallower 6-mm depth results in a faster rate of emergence than 

the 19-mm depth. The utility of pre-chilling was demonstrated both in the laboratory and at two 

field locations. Scarification in combination with pre-chilling was substantially more effective 

than scarification alone, either when scarification was done mechanically (laboratory trial) or 

with acid (field trials). For basalt milkvetch, seed scarification and planting in soil with some 

clay content may marginally improve germination and emergence, but the combination of both 

scarification and pre-chilling would further improve its germination and seedling emergence. 

This is critical information, especially for the establishment of seed fields. For rangeland 

revegetation and restoration, where an immediate stand is desirable for soil stabilization and 

competition with invasive weeds, some delay in germination delay may be beneficial in years 

with later precipitation events. As a result, a blend of scarified and untreated seed may be 

beneficial for rangeland plantings. 

Figure 3. A description of the significant (p < 0.01) interaction between two prechilling 

and two scarification treatments for cumulative germination of seed of NBR-1 Germplasm 

of basalt milkvetch (BMV) across 10 weeks in Laboratory Experiment 1. Presented here 

are least-squares means and standard errors for cumulative germination of prechilled 

scarified (PC SC) seed, prechilled unscarified (PC UN) seed, nonchilled scarified (NC SC) 

seed, and nonchilled unscarified (NC UN) seed (Jones et al. 2016). 

PC SC

PC UN

NC SC

NC UN

Week

Germination (%)

BMV
PLANT MATERIALS AND CULTURAL PRACTICES

91

Figure 4. Mean seedling densities (seedlings per 5-m row) of NBR-1 basalt 

milkvetch and their standard errors for four seed treatments and an untreated control 

at four dates at North Park (A) and three dates at Millville (B). For both locations, 

the acid + pre-chilling and sandpaper treatments displayed similar seedling densities 

(p > 0.05), but both of these treatments displayed greater seedling density than 10-

second boil, 5-minute 97% sulfuric acid, and control treatments (p < 0.05) (Jones et 

al. 2016).

 

Management Applications and Seed Production Guidelines

Seed producers will benefit by knowing how to obtain stands of these North American legume 

species for seed production. This information also will provide land managers with information to 

diversify their rangeland revegetation projects. 

acid + prechill

sandpaper

boil

acid

control

Date

North Park

Seedlings per row

sandpaper

acid + prechill

acid

boil

control

Millville

Seedlings per row

Date
PLANT MATERIALS AND CULTURAL PRACTICES

92

Presentations

Johnson, D. A.; MacAdam, J. W.; Connors, K. J.; Stettler, J. M.; Bushman, B. S.; Jones, T. A. 2015. 

High concentrations of condensed tannins in Utah trefoil (Lotus utahensis Ottley). Society for Range 

Management Annual Meeting; February; Sacramento, CA.

Johnson, D. A.; Stettler, J. M.; Bushman, B. S.; Connors, K. J.; MacAdam, J. W.; Jones, T. A. 

2015. Evaluation of Utah trefoil (Lotus uathensis Ottley) collections for rangeland 

restoration/revegetation in the southern Great Basin and Colorado Plateau. National Seed 

Conference; April; Santa Fe, NM.

Publications

Bushman, B. S.; Johnson, D. A.; Connors, K. J.; Jones, T. A. 2015. Germination and seedling 

emergence of three semiarid western North American legumes. Rangeland Ecology and 

Management 68: 501-506. 

Johnson, D. A.; Bushman, B. S.; Connors, K. J.; Bhattarai, K.; Jones, T. A.; Jensen, K. B.; Parr, 

S. D.; Eldredge, E. P. 2015. Notice of release of Fanny Germplasm, Carmel Germplasm, and 

Bonneville Germplasm Searls’ prairie clover: selected class of natural germplasm. Native Plants 

Journal 16: 265-275.

Jones, T. A.; Johnson, D. A.; Bushman, B. S.; Connors, K. J.; Smith, R. C. 2016. Seed dormancy 

mechanisms in basalt milkvetch and western prairie clover. Rangeland Ecology and Management 

69. (Accepted 12/9/2015).

Additional Products

 Germplasm releases for basalt milkvetch, western prairie clover, and Searls’ prairie clover.

 Seed production guidelines and planting guides.

 Peer-reviewed publications.
PLANT MATERIALS AND CULTURAL PRACTICES

93

Project Title Breeding Biologies and Pollinators for Silverleaf 

Phacelia

Project Agreement No. 11-IA-11221632-010

 

Principal Investigators and Contact Information

James H. Cane, Research Entomologist 

USDA ARS Bee Biology and Systematics Lab

Utah State University

Logan, UT 84322-5310 

435.797.3879, Fax 435.797.0461

Jim.Cane@ars.usda.gov

Project Description

Objectives

All of the wildflower species thus far studied for prospective plant community restoration in the 

Great Basin sage-steppe benefit from, or require, pollinators for ample fruit and seed production. 

Silverleaf phacelia, Phacelia hastata (Boraginaceae) is a widespread and widely adaptable 

perennial forb of the Intermountain West, Rockies and Sierra Nevada, found growing from sagesteppe to alpine habitats. We sought to evaluate its pollination needs and pollinators, both to 

inform seed growers as well as to evaluate its value to wild bee communities. 

Methods

To evaluate this plant species’ breeding biology, we first acquired seed from the Plant Material 

Center in Bridger, Montana. It was sourced from Anacdona Montana for mine tailing 

reclamation. When we directly seeded outside the fall before, seeds germinated readily but the 

tiny seedlings were easily lost to desiccation. After some trials, we developed an effective light 

soil mix and greenhouse propagation protocol for transplants. For the following years,

transplants were installed in holes in weed barrier, and lightly shaded from sun damage with 

Reemay floating row cover for four weeks. Survivors came to bloom profusely the following 

year.

Our intent was to use hand pollinations to compare fruit and seed sets at flowering plants caged 

outside. We established 50 transplants that successfully wintered. They were caged before bloom 

and manually pollinated (selfing and outcrossing) to establish the species’ breeding biology. 

Bloom was spectacular, enough to obscure foliage below. However, the flowers are small and 

worse, their stigmas are miniscule, with only enough surface area to receive a few dozen pollen 

grains. Even with magnifying visors, we struggled to see the stigma clearly when trying to apply 

self- or outcross pollen while hunched over on the ground in the cage. Probably as a 

consequence, our daily manual pollinations seemed rarely effective. 

We therefore propagated a new set of transplants, but used a scheme to let bees do the 

pollinating. We transplanted trios and singletons of silverleaf phacelia on campus, at our 
PLANT MATERIALS AND CULTURAL PRACTICES

94

common garden, and at homes of colleagues with xeriscape gardens around Logan, UT. 

Singleton plants could only receive self-pollen from visiting bees whereas plant trios could be 

outcrossed by bees moving between plants. About 50% of the plants survived to flower and set 

seed. Racemes and spent flowers were persistent. We collected them when dry but before any 

losses. Dried flowers (n = 2200) were counted manually for 18 racemes taken from 18 plants. 

Kevin Connors at the USDA-ARS Forage and Range Lab then cleaned the samples individually 

with ease. I then manually counted the seeds. 

To begin characterizing the pollinator fauna of silverleaf phacelia growing in the wild, several 

flowering populations in northern Utah and Nevada were sampled for floral visitors. We 

collected along haphazard transects counting all blooming individuals inspected, and collecting 

only those floral visitors seen on first glance (that is, not waiting for additional arrivals). 

Specimens were killed, pinned, labeled and identified. By this method, we can calculate densities 

of each bee species on a per plant basis and compare these values with the other 14 rangeland 

forbs that we have sampled in identical manner. 

Results and Discussion

From 937 hand-pollinated flowers on 19 caged plants and 76 racemes, we only obtained 54 

plump seeds (out of 3748 ovules, or a paltry 1.4% seed set). Clearly, the species does not autopollinate, but requires a pollinator’s visit. With a new cohort of transplants, we then evaluated 

the need for outcrossing using outplanted singletons and trios of plants all accessible to freeflying pollinators. With bees doing the pollinating, the isolated singleton plants experienced 55% 

seed set (range 18-96%), or a seed for every two flowers. It is apparent that the species is selffertile. Outcrossing yielded a somewhat higher average seed set (73%) but varied widely. Note 

that I calculate this on a per flower basis and not per ovule, as it is not apparent to me if all four 

ovules per flower can regularly yield a mature seed. From our data, I conclude that it is enough 

for a bee to visit the flowers of silverleaf phacelia for plentiful seed production.

Floral visitors were all bees plus one species of pollen wasp (Pseudomasaris). Of the 15 

prevalent forbs whose pollinators we have sampled in the Great Basin, silverleaf phacelia is tied 

with Lomatium dissectum as the most intensely visited forb, with every 3rd plant hosting a wild 

bee (at the other extreme, compare with Achillea, which attracted one bee every 75 flowering 

plants). Flowering P. hastata attract a richly diverse bee fauna as well. From only 169 flowering 

individuals, we collected bees representing 13 genera of native bees, including species of 

bumblebees, Osmia, Eucera and Anthidium, bee genera that we see at many other flowering 

forbs in the sage-steppe and higher elevations in and around the Great Basin. We conclude that 

silverleaf phacelia has great potential for fostering diverse elements of Great Basin bee 

communities that are active in the late spring/early summer, with excellent prospects for 

commercial seed growing, harvest, cleaning, and later seeding into post-fire habitats. 

Future plans

I will continue to seek out wild populations of P. hastata in the Great Basin from which to 

quantitatively sample their pollinator faunas, as from our small survey, it appears that the species 

attracts a particularly wide diversity of native bees in abundance.
PLANT MATERIALS AND CULTURAL PRACTICES

95

Publications

Love, B.; Cane, J. H. [In press]. Direct effects of wildfire on a bee community: natural history 

and fire characteristics determine persistence. Ecological Entomology.

Cane, J. H.; Love, B. [In press]. Bee community preferences among common sage-steppe 

wildflowers developed for post-fire restoration. Natural Areas Journal. 

Cane, J. H.; Tepedino, V. J. [In review]. Gauging the effect of honey bee pollen collection on 

native bee communities. Ecol. Letters.

Presentations

Cane, J. 2015. Understanding bees and some restoration forbs that feed them on the Colorado 

Plateau. Colorado Plateau Restoration Workshop; 29 April - 2 May; Moab, UT. Invited. 

Management Applications and Seed Production Guidelines

Bees will be necessary for pollination of P. hastata. Without pollinators, seed set is 1% of its 

potential. In wild lands, the species attracts diverse bees that should be capable of pollination. In 

cultivation, honey bees seek this species avidly and should be good pollinators. Germination 

benefits from cold wet stratification. The tiny seedlings are very susceptible to desiccation and 

they may establish better under spun-bonded polyester row cover for the first spring. 
PLANT MATERIALS AND CULTURAL PRACTICES

96

Project Title Native Forb Increase and Research at the Great Basin 

Research Center

Project Agreement No. 11-JV-11221632-009, 12-JV-11221632-050

Principal Investigators and Contact Information

Kevin Gunnell, GBRC Project Leader

Utah Division of Wildlife Resources 

Great Basin Research Center

494 West 100 South

Ephraim, UT 84627

435.283.4441, Fax 435.283.2034

kevingunnell@utah.gov 

Danny Summers, GBRC Coordinator

Utah Division of Wildlife Resources

Great Basin Research Center

494 West 100 South

Ephraim, UT 84627

435.283.4441, Fax 435.283.2034

dannysummers@utah.gov 

Project Description

Cushion Buckwheat

Cushion buckwheat (Eriogonum ovalifolium) is a mat forming perennial forb with distribution 

across the intermountain west in a wide variety of soils and plant communities in elevations from 

650 - 4,120 m. Because of its wide distribution, there is potential for use of this species in 

revegetation and restoration efforts but there are limited amounts of commercially available seed. 

There is a need to assess the feasibility of seed production from this species over an extended 

period of time to identify populations that meet the production needs of growers, but are also 

adapted to the needs of revegetation and restoration projects. Seed production information will 

be assessed from a common garden in Ephraim, Utah. Drought tolerance adaptation will be 

assessed from a common garden at the Desert Experiment Range in southwest Utah. 

Objectives

1. Assess seed production of multiple native collected accessions of cushion buckwheat and 

G1 production seed from those accessions to test if seed production is a heritable trait. 

2. Evaluate drought tolerance of the same accessions with a common garden planted at the 

Desert Experimental Range. 

Methods

In the fall of 2013 a common garden of the top 11 producing accessions (Table 1) from a prior 

common garden study, along with the first generation daughter plants (G1) of the same 

accessions, were planted on the Snow Field Station (SFS) in Ephraim, Utah and the Desert 

Experimental Range (DER) located in Millard County, Utah. The annual precipitation at the SFS 
PLANT MATERIALS AND CULTURAL PRACTICES

97

and DER is 13 inches and 6 inches, respectively (PRISM Climate Group 2015). At the SFS, ten 

plants of each accession and generation were planted in randomized blocks replicated four times. 

Seedlings were planted into weed barrier fabric and thoroughly watered in at the time of 

transplanting to minimize the effects of transplanting. No supplemental water was given after the 

initial transplant. The same layout was used at the DER, but the number of plants was reduced to 

five and no weed barrier fabric was used. Mortality, seed production and seed size were 

monitored on the Ephraim study site. Mortality was monitored on the DER site. Production was 

estimated by calculating the mean production of plants and extrapolating to a field setting with 6 

inch spacing within the row and 2 foot row spacing.

Final Results and Discussion

The estimated mean production during the second growing season of 2015 ranged from 10.3 -

44.0 kg/ha (9.2-97.0 lbs/ha) (Figure 1). The highest producing accession in 2015 was U20-G1 

and the lowest producing accession was U8-G1 in 2015. One accession (U13) had a significant 

difference between the production of the original collection generation compared with the 

production of the G1 generation (Figure 1). Accessions that had an estimated production greater 

than 25 kg/ha for both the original and G1 generations included U11, U20, U23, and U27 (Figure 

1). 

As was expected, survival was substantially higher on the SFS than at the DER. Only one 

accession (U9-G1) had less than 50% survival on the SFS, whereas all of the accessions on the 

DER had 50% or less survival (Figure 2). Three accessions (U11, U27, U30) had a significant 

difference between the survival of the original collection generation compared with the survival 

of the G1 generation on the DER, and four accessions (U11, U13, U20, U9) had a significant 

difference between survival on the SFS. In all but two accessions (U27 and U9) that showed 

significant difference in survival, survival was higher in the G1 generation than the original 

collection generation (Figure 2). Accessions that had a mean survival greater than 25% for both 

the original and G1 generations included U13, U20, U23, U29, and U9 (Figure 2).

Table 1. Cushion buckwheat (Eriogonum ovalifolium) germplasm sources.

Lot # Site Ecoregion

EROV-U11-2002 Sand Pass 13k Lahontan Sagebrush Slopes

EROV-U13-2002 Toano 13q Carbonate Woodland Zone

EROV-U20-2005 Crittenden Res. 13r Central Nevada High Valleys

EROV-U23-2005 Crittenden Res. 80a Dissected High Lava Plateau

EROV-U27-2005 Newcastle 13c Sagebrush Basins and Slopes

EROV-U28-2005 Jungo Road 13z Upper Lahontan Basin

EROV-U29-2005 Cobre 80a Dissected High Lava Plateau

EROV-U30-2004 Hwy 26 mm 280-281 12g Eastern Snake River Basalt Plains

EROV-U7-2002 Pequop Foothills 13p Carbonate Sagebrush Valleys

EROV-U8-2002 North Battle Mountain 13m Upper Humboldt Plains

EROV-U9-2002 Adobe Hill 13m Upper Humboldt Plains

The low seed production of the tested accessions suggests that cushion buckwheat has limited 

ability for commercial production. However, the common garden study was conducted under 

dryland conditions and production may be increased with increased resources such as irrigation 
PLANT MATERIALS AND CULTURAL PRACTICES

98

and fertilization. Our results also suggest that seed production remains similar across generations 

and is likely a heritable trait in this species. 

Survival was generally good in the drought conditions found at the DER showing that this 

species is adapted to meet the needs of restoration in arid environments. In addition, several of 

the accessions with the highest survival at the DER (U20 and U23) also had some of the highest 

seed production (Figures 1 and 2). Survival was variable between generations in several 

accessions suggesting that drought tolerance may not be a heritable trait in this species (Figure 

2).

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

U11

U11-G1

U13

U13-G1

U20

U20-G1

U23

U23-G1

U27

U27-G1

U28

U28-G1

U29

U29-G1

U30

U30-G1

U7

U7-G1

U8

U8-G1

U9

U9-G1

2015

Mean production kg ha

-1

Figure 1. The 2015 mean (+/- SE) estimated production of original and G1 generations of 11 different 

cushion buckwheat accessions on the Snow Field Station (SFS). 
PLANT MATERIALS AND CULTURAL PRACTICES

99

Figure 2. Mean (+/- SE) 2 year survival of original and G1 generations of 11 accessions of 

cushion buckwheat on (A) the Desert Experiment Range (DER) and (B) the Snow Field 

Station (SFS).

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

U11

U11-G1

U13

U13-G1

U20

U20-G1

U23

U23-G1

U27

U27-G1

U28

U28-G1

U29

U29-G1

U30

U30-G1

U7

U7-G1

U8

U8-G1

U9

U9-G1

2015

Percent Survival

Desert Experimental Range (DER)

A

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

100

U11

U11-G1

U13

U13-G1

U20

U20-G1

U23

U23-G1

U27

U27-G1

U28

U28-G1

U29

U29-G1

U30

U30-G1

U7

U7-G1

U8

U8-G1

U9

U9-G1

2015

Percent Survival

Snow Field Station (SFS)

B
PLANT MATERIALS AND CULTURAL PRACTICES

100

Forb Island

Due to the high cost of native forb species land managers will be more discretionary about when 

and where they use this important plant material. The use of N-Sulate fabric (Dewitt Co.) on 

agronomic field plantings increased germination up to 1000 fold for some species. The fabric is 

light permeable, increases heat, and improves moisture retention during the germination period. 

Seed bed preparation combined with the use of N-Sulate frabic for added heat and moisture 

retention could improve germination and establishment in wildland settings. If germination and 

establishment of native forb species is increased with this methodology, there is the potential to 

use the method to create "islands" of plant material as a seed source for future natural dispersal 

across a restoration site. 

Objectives

1. Assess the effects of N-Sulate fabric on the germination, establishment, and survival of 

14 native forb species on four wildland sites. 

Methods

The study was replicated at four sites: Hatch Ranch, Lookout Pass and Fountain Green sites are 

in the Great Basin, and the Gordon Creek site is in the Colorado Plateau. The annual 

precipitation for the Hatch Ranch, Lookout Pass, Fountain Green, and Gordon Creek sites are 13 

inches, 13 inches, 12 inches, and 14 inches, respectively (PRISM Climate Group 2015). On each 

site two seed mixes (Table 2) and a control with covered and uncovered treatments were seeded 

in 1.5 x 7.6 m plots in a randomized block design with 5 replicated blocks. Plots were treated 

with a dixie harrow prior to seeding to remove standing plant material and prepare the seed bed. 

The study was replicated in 2009 and 2010 on all four sites. Density of seeded species and cover 

of cheatgrass (Bromus tectorum), annual weeds, and perennial grass was collected in twelve 0.25 

m quadrats within each plot. Data was collected 1, 2, and 5 years post seeding. Seeded Agoseris

species were combined in analysis due to difficulty in field identification.

Table 2. Seed mixes and seeding rate for N-Sulate forb island study.

Mix Species Code Scientific Name Common Name PLS m-2

1 LIPE2 Linum perenne blue flax 'Appar' 47.15

POFE Poa fendleriana muttongrass 49.51

CLSE Cleome serrulata rocky mountain beeplant 47.25

LUAR3 Lupinus argenteus silvery lupine 33.80

SPGR2 Sphaeralcea grossulariifolia gooseberryleaf globemallow 46.18

BASA3 Balsamorhiza sagittata arrowleaf balsamroot 41.87

HEBO Hedysarum boreale northern sweetvetch 'Timp' 31.65

PEPA6 Penstemon pachyphyllus thickleaf penstemon 42.41

2 AGGR Agoseris grandiflora bigflower agoseris 31.75

AGHE2 Agoseris heterophylla annual agoseris 29.60

NIAT Nicotiana attenuata coyote tobacco 43.06

LONU2 Lomatium nudicaule barestem biscuitroot 38.75

ARMU Aremone munita flatbud pricklepoppy 39.93

HEMUN Heliomeris multiflora nevadensis Nevada goldeneye 37.14

THMI5 Thelypodium milleflorum manyflower thelypody 35.95
PLANT MATERIALS AND CULTURAL PRACTICES

101

Final Results and Discussion

Density was higher for seven of the 

seeded species on plots covered with NSulate fabric than those without in the 

first sample year. The greatest difference 

in initial germination was seen in blue 

flax and the Agoseris spp. However, 

there was no difference in density 

between treatments for any species after 

five years and six of the seeded species 

were not sampled in any plot. Blue flax, 

arrowleaf balsamroot, gooseberryleaf 

globemallow, Nevada goldeneye, and 

barestem biscuit root had the greatest 

survival over time, but survival did not 

appear to be influenced by treatment 

(Figure 3 and Figure 4). Site influenced 

effectiveness of the N-sulate fabric with 

the Gordon Creek, Hatch Ranch, and 

Lookout Pass sites displaying 

significant difference in the density of 

seeded species between covered and 

uncovered plots, but Fountain Green 

displaying no difference. The Hatch 

Ranch site had the largest difference 

between covered and uncovered plots 

after 1 year and also had the highest 

density in both treatments after five 

years (Figure 5). The weedy species 

cheatgrass (Bromus tectorum) was 

abundant on the Fountain Green and 

Lookout Pass sites. N-sulate fabric 

appears to have increased the cover of 

cheatgrass in the first sample years, but 

the effect was not observed in 

subsequent sample years (Figure 6). 

The use of N-Sulate fabric in wildland 

settings has the potential to increase the 

initial germination of native forb 

species, but had limited impact on the 

long-term persistence of most species tested in this study. Site influences the success of the NSulate fabric treatment with indications that the method may be more effective on drier, hotter 

sites. Caution should be used on sites with weedy species as the method may also increase 

undesirable species which can compete with the desired species. 

Figure 3. Mean density (+/- SE) of mix 1 species for A) 1 year, 

B) 2 years, and C) 5 years post seeding.

0

2

4

6

8

1 0

1 2

Agoseris spp. ARMU HEMUN LONU2 NIAT THMI5

Density/m2

C

0

2

4

6

8

1 0

1 2

Agoseris spp. ARMU HEMUN LONU2 NIAT THMI5

Density/m2

B

0

2

4

6

8

1 0

1 2

Agoseris spp. ARMU HEMUN LONU2 NIAT THMI5

Density/m2

Covered

Uncovered

A
PLANT MATERIALS AND CULTURAL PRACTICES

102

Figure 4. Mean density (+/- SE) of mix 2 species 

for: A) 1 year, B) 2 years, and C) 5 years post 

seeding.

Figure 5. Mean density (+/- SE) of seeded species 

by site for: A) 1 year, B) 2 years, and C) 5 years 

post seeding.

0

1

2

3

4

5

6

7

BASA3 CLSE HEBO LIPE2 LUAR3 PEPA6 POFE SPGR2

Density/m2

C

0

1

2

3

4

5

6

7

BASA3 CLSE HEBO LIPE2 LUAR3 PEPA6 POFE SPGR2

Density/m2

B

0

1

2

3

4

5

6

7

BASA3 CLSE HEBO LIPE2 LUAR3 PEPA6 POFE SPGR2

Density/m2

Covered

Uncovered

A

0

10

20

30

40

50

60

70

80

FG GC HR L P

Mean Cover (%)

C

0

10

20

30

40

50

60

70

80

FG GC HR L P

Mean Cover (%)

B

0

10

20

30

40

50

60

70

80

FG GC HR L P

Mean Cover (%)

Covered

Uncovered

A
PLANT MATERIALS AND CULTURAL PRACTICES

103

Wildland Forb Seeding Methods

Currently, seed mixes used for restoration generally do not include native forb species, primarily 

due to their high cost. Because these species have not been included in past restoration efforts 

there is a lack of information about planting and establishing native forb species in wildland 

settings. As these native forbs become more available on the market, the lower costs should 

facilitate land manager's ability to include these species in seed mixes used for restoration. This 

creates a need to determine the best methods of establishing native forb species in wildland 

settings. 

Objectives

1. Evaluate native forb establishment in Wyoming big sagebrush (Artemisia tridentata ssp.

wyomingensis) using four different mechanical planting methods; broadcast seeding 

followed by a Lawson aerator, Dixie harrow or Ely chain, and drill seeding.

2. Evaluate impact of treatments on other components of the community.

Methods

The study was established on two sites (referred to as North and South) in Tooele County, Utah. 

Annual precipitation at both sites is 330 mm (13 in) (PRISM Climate Group 2015). Five 

treatments were done in 30.5 x 45 m (100.1 x 147.6 ft) plots in a randomized block design with 

two blocks at each site. The study was replicated in 2008 and 2009 at each site. The five 

treatments include an untreated control, broadcast seeding followed by either a Lawson aerator, 

Dixie harrow or Ely chain, and drill seeding using a Truax Rough Rider no-till drill. Nine forb 

species were seeded (Table 3) on each treatment except the control. Density of perennial species, 

cover of all species, and basic ground cover was sampled in 100 random 0.25 m quadrats in each 

plot. Data was sampled 1 year, 2 years, and 6 years post treatment. 

Figure 6. Mean cover of cheatgrass (Bromus tectorum) by site for: A) 1 year, B) 2 years, and C) 5 

years post seeding.

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

C

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

B

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

Covered

Uncovered

A

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

C

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

B

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

Covered

Uncovered

A

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

C

0

10

20

30

40

50

60

FG GC HR L P

Density/m2

B

0

10

20

FG GC HR L P

De
PLANT MATERIALS AND CULTURAL PRACTICES

104

Table 3. Seed mix and seeding rate for the wildland forb seeding methods study.

Species Code Scientific Name Common Name PLS m-2

ASUT Astragalus utahensis Utah milkvetch 21.85

BASA3 Balsamorhiza sagittata arrowleaf balsamroot 24.54

CRAC2 Crepis acuminata tapertip hawksbeard 5.17

HEBO Hedysarum boreale northern sweetvetch 6.46

LIPE2 Linum perenne blue flax 'Appar' 65.01

LUAR3 Lupinus argenteus silvery lupine 2.91

PEPA8 Penstemon palmeri palmer penstemon 52.31

PEEA Penstemon eatonii firecracker penstemon 34.23

SPMU2 Sphaeralcea munroana munro globemallow 46.50

Final Results and Discussion

Because of different sowing rates, results for seeded species are presented in percentages of 

sampled density to seeded density for each species. Munro's globemallow (Sphaeralcea 

munroana) was excluded from results because it was present prior to seeding and we were 

unable to differentiate seeded plants from naturally occurring plants. Total survival of all seeded 

species was less than 6% on all treatments. The harrow and chain treatments had the highest 

survival in the first and second years following treatment, but long term persistence was higher 

on the aerator treatment six years after treatment. The drill treatment had the lowest survival in 

all sample years (Figure 7). Site also influenced survival of species with the total survival of 

seeded species much higher in all sample years on the north site (Figure 8).

The effect of the mechanical treatments on individual species survival varied. Blue flax (Linum 

perenne) had the highest survival of any species on all four treatment types in all sample years. 

Utah milkvetch (Astragalus utahensis) had the highest emergence on the harrow treatments one 

year after treatment, but survival was similar to the chain treatment two years after treatment and 

both the chain and aerator treatment six years after treatment. Northern sweetvetch (Hedysarum 

boreale) had the highest germination on the chain treatment one year after treatment, but survival 

declined in subsequent years. Arrowleaf balsamroot (Balsamorhiza sagittata) had limited 

survival the first year, but survival increased and was similar on all treatments by the sixth year 

after treatment. Silvery lupine (Lupinus argenteus) had good survival on all treatments in the 

initial year following treatment, but was not sampled six years after treatment on any treatment 

plot. Palmer penstemon (Penstemon palmeri) and firecracker penstemon (P. eatonii) had very 

low survival on all treatments, but survival was lowest on the drill treatment and similar on all 

other treatments. Tapertip hawksbeard (Crepis acuminata) had almost no survival on any 

treatment (Figure 7).

The effect of the mechanical treatments on other components in the community is an important 

consideration. Wyoming big sagebrush cover was affected differently by each of the treatments. 

The Dixie harrow treatment had the highest reduction in sagebrush cover followed by the 

Lawson aerator, Ely chain, while the Truax drill had limited reduction on sagebrush cover the 

first year after treatment. Sagebrush cover increased in each subsequent sample year on all 

treatments including the control, but the effect of treatment remained the same in all sample 

years (Figure 9). The treatments with the highest disturbance (i.e., harrow, drill, and aerator) also 
PLANT MATERIALS AND CULTURAL PRACTICES

105

exhibited higher cover of cheatgrass (Bromus tectorum) than the drill treatment and control plots 

in all sample years (Figure 10). 

The results from the study show that survival of seeded forb species can be improved in a 

Wyoming big sagebrush community with the appropriate seeding methodology. However, 

selection of the best methodology is contingent on a number of factors including: species to be 

seeded, objectives in sagebrush reduction, and weedy species that may be released. 

Figure 7. Mean survival of seeded forb species by treatment and year post treatment.

0

1

2

3

4

5

6

7 Aerator Chain Control Drill Harrow Aerator Chain Control Drill Harrow Aerator Chain Control Drill Harrow

1 2 6 Survival (%)

Year Post Treatment

PEPA8

PEEA

LUAR3

LIPE2

HEBO

CRAC2

BASA3

ASUT
PLANT MATERIALS AND CULTURAL PRACTICES

106

Figure 8. Mean survival of seeded species for all treatments by site and year post treatment.

Figure 9. Mean cover of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) by 

treatment and year post treatment.

0

0.5

1

1.5

2

2.5

3

3.5

4

North South North South North South

1 2 6 Survival (%)

Year Post Treatment

PEPA8

PEEA

LUAR3

LIPE2

HEBO

CRAC2

BASA3

ASUT

0

2

4

6

8

1 0

1 2

1 4

1 6

Aerator Chain Control Drill HarrowAerator Chain Control Drill HarrowAerator Chain Control Drill Harrow

1 2 6 Mean Cover (%)

Year Post Treatment
PLANT MATERIALS AND CULTURAL PRACTICES

107

Figure 10. Mean cover of cheatgrass (Bromus tectorum) by treatment and year post treatment.

Native Seed Increase

Objectives

1. Increase seed from wildland collections to support further research and increase 

distribution of native seed to commercial growers.

2. Develop and test methods to increase germination and establishment of native species in 

agronomic settings.

Methods

Work was done in conjunction with the USFS Rocky Mountain Research Station Provo Shrub 

Sciences Lab wildland seed collection project. Selected species and accessions of wildland 

collected seed will be planted on the Utah Division of Wildlife Resources (UDWR) farms in 

Fountain Green, UT or the Snow College farm in Ephraim, UT for the purpose of seed increase. 

Seed will be either direct seeded into fields, or propagated in the greenhouse for plug 

transplanting depending on the amount of seed available. 

Production fields will be maintained and harvested to maximize seed production of native 

species. When opportunities arise, development of propagation protocols and research for 

increased establishment and production will be conducted. 

Results

Seed from 11 species with 57 accessions were harvested in 2015 (Table 4). Four species with 33 

different accessions was seeded or transplanted into increase beds in the spring or fall of 2015 

0

5

1 0

1 5

2 0

2 5 Aerator Chain Control Drill Harrow Aerator Chain Control Drill Harrow Aerator Chain Control Drill Harrow

1 2 6 Mean Cover (%)

Year Post Treatment
PLANT MATERIALS AND CULTURAL PRACTICES

108

(Table 5). The foundation field of UDWR Tetra Great Basin wildrye was expanded by clonally 

splitting mature plants and transplanting rootstock into randomized plots. 

Table 4. Native species harvested in 2015.

Code Species # of Accessions Location

ASFI Astragalus filipes 1 Ephraim

ARMAF Arenaria macradenia ferrisea 1 Ft. Green

ASTER Aster sp. 1 Ft. Green

CRAC2 Crepis acuminata 3 Ft. Green

CRYPT Cryptantha sp. 1 Ft. Green

DAOR2 Dalea ornata 1 Ephraim

ENNUN Enceliopsis nudicaulis 3 Ft. Green

HEMUN Heliomeris multiflora nevadensis 5 Ft. Green

LECI4 Leymus cinereus 30* Ephraim

HECO26 Hesperostipa comata 7 Ft. Green

PEPA6 Penstemon pachyphyllus 4 Ft. Green

*Foundation source of UDWR Tetra Great Basin Wildrye selected release. Accessions are pooled 

when harvested.

Table 5. Native species sown in 2015.

Code Species # of Accessions Location

HEMUN Heliomeris multiflora nevadensis 5 Ft. Green

PEPA6 Penstemon pachyphyllus 17 Ft. Green`

LILEL2 Linum lewisii lewisii 10 Ft. Green

IPAG Ipomopsis aggregata 1 Ft. Green

Presentations

Gunnell, Kevin L. 2015. Update of native plant research and activities at the Great Basin 

Research Center, Ephraim, UT. Great Basin Native Plant Project Annual Meeting; 2015 

February 17-19; Boise, ID.

References

PRISM Climate Group, [Database]. (2015). Oregon State University. 1981-2010 Climatology 

Normals. Available: http://prism.oregonstate.edu.
PLANT MATERIALS AND CULTURAL PRACTICES

109

Project Title Plant Material Work at the Shrub Science Lab 

Project Agreement No. 13-IA-11221632-161

Principal Investigators Scott Jensen, Botanist

Rocky Mountain Research Station 

Grassland, Shrubland and Desert Ecosystem Program

735 N. 500 E.

Provo, UT 84606-1865

801.356.5124, Fax 801.375.6968

sljensen@fs.fed.us

Project Description

Wildland Seed Collection

Seed collection efforts in 2015 (Table 1) were focused on harvesting specific populations of 

thickleaf penstemon (Penstemon pachyphyllus), Nevada showy goldeneye (Heliomeris multiflora

var. nevadensis), skyrocket gilia (Ipomopsis aggregata) and basin wildrye (Leymus cinereus) 

where additional seed is needed for current increase projects. 

Table 1. Species and number of sources collected in 2015.

Family Common Name # Collections

Asteraceae Nevada showy goldeneye 7

Polemoniaceae skyrocket gilia 5

Scrophulariaceae thickleaf penstemon 7

Poaceae Basin wildrye 6

The Effect of Sowing Depth on Establishment of 20 Forbs Native to the Great Basin

Objectives

Evaluate the effect of field planting depth in loam textured soils on seedling emergence for 20 

forbs native to the Great Basin. 

Results and Discussion

This study was initially implemented in 2013 and fully replicated in fall 2014. In 2015, 

persistence data has been collected on the 2013 plantings and emergence data has been collected 

on the 2014 planting. Data collection is complete for this study. Analysis is ongoing. 

Evaluating Methods of Pairing Seed Sources to Restoration Sites Using Basin Wildrye (Leymus 

cinereus)

Objectives

In section one of this study we evaluate a leading surrogate, provisional seed zones (PSZ) 

(Bower et al. 2014, Kramer et al. 2015) as a method for matching basin wildrye source 

populations to representative restoration sites.
PLANT MATERIALS AND CULTURAL PRACTICES

110

As the locally adapted model of matching seed supplies to restoration sites is relatively new in 

large scale restoration efforts and in direct competition with the agricultural cultivar model 

(Jones 2009), common basin wildrye cultivars are included in the trial. In section two of this 

study we compare establishment success between pooled local populations and commercially 

available basin wildrye cultivars. 

The cultivars Magnar and Trailhead (USDA 2012a, b) originate from regions outside the Great 

Basin but have historically been seeded extensively in the intermountain west. To our knowledge 

Great Basin populations have not been extensively evaluated for cultivar potential. In section 

three of this study we use a ‘pick the winner’ approach, emphasizing establishment ability to 

evaluate whether any individual regional source shows merit following the cultivar model of 

sourcing plant materials.

In section four of this study we evaluate how the population level characteristics of ploidy, seed 

weight, clean-out percentage, and viability relate to establishment. 

This study was initially implemented in 2013 and fully replicated in fall 2014. In 2015, 

persistence data was collected on the 2013 plantings and emergence data collected on 2014 

plantings. Establishment data will be collected in the spring of 2016, wrapping up this phase of 

the study. 

Forb Islands: Possible Techniques to Improve Forb Seedling Establishment for Diversifying 

Sagebrush-Steppe Communities

Objectives

This is a multiagency cooperative study assessing seed and ground treatments to improve forb 

establishment. Rocky Mountain Research Station involvement in this study includes locating, 

preparing and maintaining the Spanish Fork test site, selection and preparation of 10 native forb 

species and associated seed treatments totaling 33 combinations, weather station acquisition and 

deployment, and supplying tractor and seeder to install the study. The study was installed at three 

sites in Utah and Idaho. For complete details see Douglas A. Johnson’s write up in this report. 

Presentations

Jensen, S. L. 2015. Field testing generalized seed zones with basin wildrye (Leymus cinereus). 

Great Basin Consortium Conference; 2015 February 17-19; Boise, Idaho.

Jensen, S. L. 2015. Field testing generalized seed zones with basin wildrye (Leymus cinereus). 

National Native Seed Conference 2015; Native Plant Materials Development, Production & Use 

in Habitat Restoration; 2015 April 13-16; Santa Fe, New Mexico.

Jensen, S. L. 2015. Native forbs for restoration: the utility of provisional seed zones. Field testing 

generalized seed zones with basin wildrye (Leymus cinereus). Utah Chapter of the Society for 

Range Management; 2015 November 5-6; Moab, Utah.
PLANT MATERIALS AND CULTURAL PRACTICES

111

Additional Products

 In cooperation with the Utah Division of Wildlife Resources, Great Basin Research 

Center (GBRC) greenhouse grown plugs of: 12 sources of thickleaf penstemon from seed 

zone (15 - 20 Deg. F. / 3 – 6); two sources of Nevada showy goldeneye from seed zone 

(15 - 20 Deg. F. / 6 – 12); and three sources of Lewis flax (Linum lewisii) from zone (15 -

20 Deg. F. / 6 – 12) were transplanted into increase beds at the Fountain Green farm 

facility. Future seed harvests from these beds will serve as stock seed for these 

species/zone combinations for distribution to commercial producers. 

 Additional seed from 2015 or prior year wildland collections for 16 sources was provided 

to UDWR to grow additional plugs to augment increase beds. 

 Two species, thickleaf penstemon and yellow beeplant (Cleome lutea) were provided to 

Utah State University extension specialist Kevin Heaton in Garfield County, UT for seed 

increase. We anticipate expanding this relationship with additional seed increase efforts 

in future years. 

 Seed of two species, skyrocket gilia and cleftleaf wildheliotrope 

(Phacelia crenulata var. corrugata) were provided to Malheur Experiment Station for 

cultural practice studies. 

 Seed of 40 species was provide to USDA FS Region 4 to initiate a pollinator display 

garden at the Ruby Mountains and Jarbidge Ranger Station in Wells, NV. 

 10 bulk pounds of Blue penstemon (Penstemon cyaneus) was sent to L&H seed to 

establish increase fields. 

 110 bulk pounds of gooseberry leaf globemallow (Sphaeralcea grossulariifolia) was 

scarified for Jerry Erstrom of Quarter Circle J Seeds to increase the size of an existing 

production field. 

References

Bower, A. D.; St. Clair, B.; Erickson, V. 2014. Generalized provisional seed zones for native 

plants. Ecological Applications 24(5): 913–919.

Kramer, A. T.; Larkin, D. J.; Fant, J. B. 2015. Assessing potential seed transfer zones for five 

forb species from the Great Basin Floristic region, USA. Natural Areas Journal 35: 174-188.

Jones, T. A. 2009. Conservation biology and plant breeding: special considerations for the 

development of native plant materials for use in restoration. Ecological Restoration 27(1): 8-11.

USDA- Natural Resource Conservation Service. 2012a. Release brochure for ‘Magnar’ Basin 

wildrye (Leymus cinereus). Aberdeen, ID: U.S. Department of Agriculture, Natural Resources 

Conservation Service, Aberdeen Plant Materials Center. 2 p.

USDA- Natural Resource Conservation Service. 2012b. Trailhead Basin Wildrye Release 

Brochure. Aberdeen, ID: U.S. Department of Agriculture, Natural Resources Conservation 

Service, Aberdeen Plant Materials Center. 2 p.
PLANT MATERIALS AND CULTURAL PRACTICES

112

Project Title Native Plant Selection, Release Development, and 

Information Transfer

Project Agreement No. 11-1A-11221632-004

Principal Investigators and Contact Information 

Derek Tilley, PMC Manager 

USDA NRCS

Aberdeen Plant Materials Center

PO Box 296

Aberdeen, ID 83210

208.397.4133, Fax 208.397.3104

derek.tilley@id.usda.gov

Project Description

The Aberdeen Plant Materials Center (PMC) was involved with the testing and selecting of 

accessions of native forbs for commercial release, and with developing protocols for plant and 

seed production. The PMC also developed NRCS Plant Guides for select species. 

Hoary Tansyaster

Nine accessions of hoary tansyaster (Machaeranthera canescens) were evaluated from 2009 

through 2011 for establishment, plant growth and seed production. Accession 9076670 had the 

best establishment and stands for 2009 and 2010. It also had the best rated vigor in 2010. This 

accession also had the tallest plants in the study. The population for 9076670 is located near the 

St. Anthony Sand Dunes in Fremont County, Idaho at 1,524 m (5,000 ft) elevation. The site has 

sandy soils and supports a bitterbrush (Purshia tridentata), Indian ricegrass (Achnatherum 

hymenoides), rabbitbrush (Ericameria nauseosa), and scurfpea (Psoralidium sp.) plant 

community. The location receives between 250 and 380 mm (10 to 15 in) of mean annual 

precipitation. In 2014, accession 9076670 was officially released as Amethyst Germplasm hoary 

tansyaster.

G1 and G2 seed of Amethyst Germplasm hoary tansyaster will be maintained by the USDA 

Natural Resources Conservation Service, Aberdeen Plant Materials Center. Seed through the G5 

generation will be eligible for certification. G1 and G2 seed will be made available to 

commercial growers for distribution by the University of Idaho Foundation Seed Program and 

Utah Crop Improvement Association. Small quantities of seed will be provided to researchers by 

request to the Plant Materials Center.

Wyeth or Whorled Buckwheat

Thirty-nine accessions of Wyeth and Sulphur-flower buckwheat (Eriogonum heracleoides and E. 

umbellatum) were compared in a common garden study from 2007 through 2011. Accession 

9076546 Wyeth buckwheat showed good establishment, seed production, and longevity 

compared with the other accessions.
PLANT MATERIALS AND CULTURAL PRACTICES

113

Initial seed increase of accession 9076546 is ongoing. Release documentation is being 

developed, and official release will occur once the PMC has produced a sufficient amount of 

early generation seed. This year, the PMC produced a good quantity of seed which should be 

enough to supply initial demand. 

Douglas Dustymaiden

Fifteen accessions of Douglas’ dustymaiden (Chaenactis douglasii) were evaluated at Aberdeen 

PMC from 2009 to 2010 for establishment, growth and seed production. Following evaluation, 

accession 9076577 was chosen for further production and possible release. Accession 9076577 

was originally collected in Boise County, Idaho near Arrow Rock and Lucky Peak Reservoirs. 

The site is a mountain big sagebrush/bitterbrush community in coarse granitic soils at 960 m 

(3,150 ft) elevation. Accession 9076577 ranked at or near the top in percent establishment, plant 

vigor, height, flower production and seed yield. 

Seed increase plots of accession 9076577 were established at the PMC for early generation 

certified seed production in 2011, 2012 and 2013 with the intent to make a selected class 

germplasm release once the PMC had produced a sufficient amount of early generation seed. 

Due to repeated low establishment in seed production plantings the Douglas dustymaiden project 

was discontinued.

Flail-Vac Modifications

We have examined several techniques for harvesting light airborne seed such as that of hoary 

tansyaster. Direct combining takes relatively little time in the field, however this method yields 

correspondingly less seed due to the limitation of only getting a single harvest. Additionally it 

requires significantly more time to clean the seed compared to other methods because of the 

large amounts of inert matter collected. 

In 2013 we harvested hoary tansyaster using a standard Woodward Flail-Vac seed stripper. The 

Flail-Vac was set to harvest approximately the top 20 to 30 cm (8 to12 in) of the plants. We got 

two harvests using the Flail-Vac which yielded a total of 3.3 kg (7.3 lb), equivalent to 13.7 kg/ha 

(12.2 lb/ac). Only two harvests were possible because of the destructive nature of the Flail-Vac 

brush on the plants.

In 2015 we experimented with two modifications to the standard Flail-Vac harvester in an 

attempt to increase seed yields. We compared rigid pipes mounted to the Flail-Vac hood which 

penetrated into the plant canopy, to loops of chain that could be dragged through the plants. The 

Flail-Vac head itself was elevated above the plants so the brush did not come in contact with the 

flowers. The pipes or chains agitated the plants causing the release of seed into the air, while the 

airflow created by the Flail-Vac brushes sucked the light seed through and into the collection bin.

There were significant differences in performance of the two methods, though both were more 

effective than the standard Flail-Vac. Rigid pipes were more damaging to the plants than 

desirable. Plants got hung up on the pipes and pulled until they were uprooted or broken. We had 

to stop the tractor regularly to lift the arms and remove broken stems and plants from the front of 

the Flail-Vac; however, the seed yields were promising. The pipes effectively agitated the plant 

canopy and shook loose, ripe seed from the flowers and left non-ripe flowers and vegetation 

intact. The chain had enough weight to fall into the canopy and displace seed, but was less rigid 
PLANT MATERIALS AND CULTURAL PRACTICES

114

and caused very little, if any, damage. We experienced no broken stems or uprooted plants using 

the chain method. 

Best results for hoary tansyaster occurred driving the tractor very slowly, between 0.87 and 1.1 

km/h (1.4 and 1.8 mph) with the Flail-Vac set at 400 rpm. Lower brush speeds resulted in 

insufficient air flow, while higher speeds caused increasing amounts of seed to be sucked 

completely through the Flail-Vac and blown out the exhaust opening. 

We were able to run the chain-modified Flail-Vac eight times through a 0.4 ha (1 ac) hoary 

tansyaster field. Each harvest was run in the opposite direction as the previous. Immediately after 

a Flail-Vac pass the plants were left leaning over from the weight of the heavy chain, but after a 

day or two they had regained their upright attitude. From our eight harvests we collected a total 

of 29 kg (64 lb) of clean seed, a 500% increase compared to the non-modified Flail-Vac.

Plant Guides

NRCS Plant Guides have been developed for 21 species of forbs and grasses native to the 

Intermountain West. Plant Guides offer the most recent information on plant establishment, 

management, and seed and plant production information. General information for the species can 

also be found in our Plant Guides including: information on potential uses, ethnobotanical 

significance, adaptation, pests, and potential problems. Plant guides are available at the PLANTS 

database, www.plants.usda.gov, and at the Aberdeen Plant Materials Center website: 

www.id.nrcs.usda.gov/programs/plant.html.

Propagation Protocols

Seed production information obtained during collection evaluation and seed increase of native 

forb species was used to develop propagation protocols for Douglas’ dustymaiden, hoary 

tansyaster, nineleaf biscuitroot, fernleaf biscuitroot and Gray’s biscuitroot and Searls’ prairie 

clover. These protocols provide information on seed collection, planting, management, harvest, 

and cleaning. Propagation protocols are available at http://www.nativeplantnetwork.org.

Publications

Ogle, Dan; Peterson, Scott; St. John, Loren. 2014. Plant guide for Rocky Mountain penstemon, 

Penstemon strictus Benth. Aberdeen, ID: U.S. Department of Agriculture, Natural Resources 

Conservation Service, Aberdeen Plant Materials Center. 4 p.

Tilley, Derek. 2014. Release brochure for Amethyst germplasm hoary tansyaster, 

Machaeranthera canescens (Pursh) A. Gray. Aberdeen, ID: U.S. Department of Agriculture, 

Natural Resources Conservation Service, Aberdeen Plant Materials Center. 2 p.

Tilley, Derek. 2015. Seed production and field establishment of hoary tansyaster 

(Machaeranthera canescens). Native Plants Journal 16(1): 61-66.

Tilley, Derek. 2015. Notice of release of Amethyst Germplasm hoary tansyaster: selected class 

of natural germplasm. Native Plants Journal 16(1): 55-60.

Tilley, Derek; Ogle, Dan; St. John, Loren. 2014. Plant Guide for hoary tansyaster, 

Machaeranthera canescens (Pursh) A. Gray. Aberdeen, ID: U.S. Department of Agriculture, 

Natural Resources Conservation Service, Aberdeen Plant Materials Center. 4 p.
PLANT MATERIALS AND CULTURAL PRACTICES

115

Additional Products

 Early generation certified seed of Amethyst Germplasm hoary tansyaster is in production, 

and allocations have been made to Utah Crop Improvement and Idaho Foundation Seed 

Program.

 Early generation certified seed of Wyeth buckwheat is being produced and will be 

available through Utah Crop Improvement and University of Idaho Foundation Seed 

Program when release is approved. 
PLANT MATERIALS AND CULTURAL PRACTICES

116

Project Title Seed Production of Great Basin Native Forbs

Project No. 12-JV-11221632-066

Principal Investigators and Contact Information

Clinton C. Shock, Director/Professor

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174, Fax 541.889.7831

clinton.shock@oregonstate.edu

Erik B. Feibert, Senior Faculty Research Assistant

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174 

erik.feibert@oregonstate.edu

Joel Felix, Assoc. Professor

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174, Fax 541.889.7831

joel.felix@oregonstate.edu

Nancy Shaw, Research Botanist

USFS Rocky Mountain Research Station

322 E. Front Street, Suite 401

Boise, ID 83702

208.373.4360, Fax 208.373.4391

nancylshaw@fs.fed.us

Francis Kilkenny, Research Biologist

USFS Rocky Mountain Research Station

322 E. Front Street, Suite 401

Boise, ID 83702

208.373.4376, Fax 208.373.4391

ffkilkenny@fs.fed.us 
PLANT MATERIALS AND CULTURAL PRACTICES

117

Project Description

A five part study regarding seed production of Great Basin native forbs using subsurface drip 

irrigation (SDI) for stable, efficient seed production using small amounts of supplemental water, 

and seeding practices.

*Seven reports follow here:

1. Irrigation Requirements for Native Buckwheat Seed Production in a Semi-arid 

Environment

2. Irrigation Requirements for Seed Production of Five Lomatium Species in a Semi-Arid 

Environment

3. Irrigation Requirements for Seed Production of Five Native Penstemon Species in a 

Semi-Arid Environment

4. Prairie Clover and Basalt Milkvetch Seed Production in Response to Irrigation 

5. Native Beeplant (Cleome spp.) Seed Production in Response to Irrigation in a Semi-Arid 

Environment

6. Irrigation Requirements for Seed Production of Various Native Wildflower Species 

started in the Fall of 2012

7. Direct Surface Seeding Systems for the Establishment of Native Plants in 2015

1. Irrigation Requirements for Native Buckwheat Seed Production in a Semi-Arid 

Environment

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, Lamont D. Saunders

Malheur Experiment Station

Oregon State University, Ontario, OR 2015 

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station, Boise, ID 83704

Summary

Native buckwheats (Eriogonum spp.) are important perennials in the Intermountain West. 

Buckwheat seed are desired for rangeland restoration activities, but little cultural practice 

information is available for seed production of native buckwheat. The seed yield of Eriogonum 

umbellatum and E. heracleoides were evaluated over multiple years in response to four biweekly 

irrigations applying either 0, 1 inch of water, or 2 inches of water (total of 0, 4 inches, or 8 

inches/season). Eriogonum umbellatum seed yield was maximized by 5 to 8 inches of water 

applied per season in warmer, drier years and no irrigation was needed in cooler, wetter years. 

Averaged over ten years, seed yield of Eriogonum umbellatum was maximized by 6.5 inches of 

water applied per season. Over five seasons, seed yield of Eriogonum heracleoides was only 

responsive to irrigation in 2013, a dry year when seed yield was maximized by 4.9 inches of 

applied water.

Introduction

Native wildflower seed is needed to restore rangelands of the Intermountain West. Commercial 

seed production is necessary to provide the quantity of seed needed for restoration efforts. A 

major limitation to economically viable commercial production of native wildflower (forb) seed 
PLANT MATERIALS AND CULTURAL PRACTICES

118

is stable and consistent seed productivity over years. In native rangelands, the natural variations 

in spring rainfall and soil moisture result in highly unpredictable water stress at flowering, seed 

set, and seed development, which for other seed crops is known to compromise seed yield and 

quality. Native wildflower plants are not well adapted to croplands. They often are not 

competitive with crop weeds in cultivated fields. Poor competitiveness with weeds could also 

limit wildflower seed production. Both sprinkler and furrow irrigation could provide 

supplemental water for seed production, but these irrigation systems risk further encouraging 

weeds. Also, sprinkler and furrow irrigation can lead to the loss of plant stand and seed

production due to fungal pathogens. By burying drip tapes at 12-inch depth and avoiding wetting 

the soil surface, experiments were designed to assure flowering and seed set without undue 

encouragement of weeds or opportunistic diseases. The trials reported here tested the effects of 

three low rates of irrigation on the seed yield of Eriogonum umbellatum (Sulphur-flower 

buckwheat) and Eriogonum heracleoides (Parsnipflower buckwheat). 

Materials and Methods

Plant Establishment

Seed of Eriogonum umbellatum was received in late November in 2004 from the Rocky 

Mountain Research Station (Boise, ID). The plan was to plant the seed in the fall of 2004, but 

due to excessive rainfall in October, the ground preparation was not completed and planting was 

postponed to early 2005. To try to ensure germination, the seed was submitted to cold 

stratification. The seed was soaked overnight in distilled water on January 26, 2005, after which 

the water was drained and the seed soaked for 20 minutes in a 10% by volume solution of 13% 

bleach in distilled water. The water was drained and the seed was placed in thin layers in plastic 

containers. The plastic containers had lids with holes drilled in them to allow air movement. 

These containers were placed in a cooler set at approximately 34° F. Every few days the seed 

was mixed and, if necessary, distilled water added to maintain seed moisture. 

In late February 2005, drip tape (T-Tape TSX 515-16-340) was buried at 12-inch depth between 

two 30-inch rows of a Nyssa silt loam with a pH of 8.3 and 1.1% organic matter. The drip tape 

was buried in alternating inter-row spaces (5 ft apart). The flow rate for the drip tape was 0.34 

gal/min/100 ft at 8 psi with emitters spaced 16 inches apart, resulting in a water application rate 

of 0.066 inch/hour.

On March 3, 2005, seed of Eriogonum umbellatum was planted in 30-inch rows using a custommade small plot grain drill with disc openers. All seed was planted at 20-30 seeds/ft of row at 

0.25-inch depth. The trial was irrigated with a minisprinkler system from March 4 to April 29 

(R10 Turbo Rotator, Nelson Irrigation Corp., Walla Walla, WA) for even stand establishment. 

Risers were spaced 25 ft apart along the flexible polyethylene hose laterals that were spaced 30 ft 

apart and the water application rate was 0.10 inch/hour. A total of 1.72 inches of water was 

applied with the mini sprinkler system. Eriogonum umbellatum started emerging on March 29. 

Starting June 24, the field was irrigated with the drip system. A total of 3.73 inches of water was 

applied with the drip system from June 24 to July 7. The field was not irrigated further in 2005. 

Plant stands for Eriogonum umbellatum were uneven. Eriogonum umbellatum did not flower in 

2005. In early October, 2005 more seed was received from the Rocky Mountain Research Station 

for replanting. The empty lengths of row were replanted by hand. The seed was replanted on 

October 26, 2005. In the spring of 2006, the plant stands were excellent. 
PLANT MATERIALS AND CULTURAL PRACTICES

119

In early November 2009, drip tape was buried as described above in preparation for planting 

Eriogonum heracleoides. On November 25, 2009 seed of Eriogonum heracleoides was planted 

in 30-inch rows using a custom-made plot grain drill with disk openers. All seed was planted on 

the soil surface at 20-30 seeds/ft of row. After planting, sawdust was applied in a narrow band 

over the seed row at 0.26 oz/ft of row (558 lb/acre). Following planting and sawdust application, 

the beds were covered with row cover. The row cover (N-sulate, DeWitt Co., Inc., Sikeston, 

MO) covered four rows (two beds) and was applied with a mechanical plastic mulch layer. The 

field was irrigated for 24 hours on December 2, 2009 due to very dry soil conditions.

After Eriogonum heracleoides had emerged, the row cover was removed in April, 2010. The 

irrigation treatments were not applied to Eriogonum heracleoides in 2010. Stands of Eriogonum 

heracleoides were not adequate for yield estimates. Gaps in the rows were replanted by hand on 

November 5, 2010. The replanted seed was covered with a thin layer of a mixture of 50 percent 

sawdust and 50 percent hydro seeding mulch (Hydrostraw LLC, Manteno, IL) by volume. The 

mulch mixture was sprayed with water using a backpack sprayer. 

Irrigation for Seed Production 

The planted strips were divided into plots 30 ft long (Eriogonum umbellatum in April 2006 and 

Eriogonum heracleoides in April 2011). Each plot contained four rows of each species. The 

experimental designs were randomized complete blocks with four replicates. The three 

treatments were a non-irrigated check, 1 inch of water applied per irrigation, and 2 inches of 

water applied per irrigation. Each treatment received 4 irrigations that were applied 

approximately every 2 weeks starting with bud formation and flowering. The amount of water 

applied to each treatment was calculated by the length of time necessary to deliver 1 or 2 inches 

through the drip system. Irrigations were regulated with a controller and solenoid valves. After 

each irrigation, the amount of water applied was read on a water meter and recorded to ensure 

correct water applications. Irrigation dates are found in Table 1. 

Flowering, Harvesting, and Seed Cleaning 

Flowering dates for each species were recorded (Table 1). The Eriogonum umbellatum plots 

produced seed in 2006, in part because they had emerged in the spring of 2005. Eriogonum 

heracleoides started flowering in 2011. Each year, the middle two rows of each plot were 

harvested when seed of each species was mature (Table 1). Seed was harvested with a small plot 

combine. Eriogonum umbellatum and Eriogonum heracleoides seeds did not separate from the 

flowering structures in the combine. In 2006, the unthreshed seed of Eriogonum umbellatum was 

taken to the U.S. Forest Service Lucky Peak Nursery (Boise, ID) and run through a dewinger to 

separate seed. The seed was further cleaned in a small clipper seed cleaner. In subsequent years, 

the unthreshed seed of both species was run through a meat grinder to separate the seed. The 

seed was further cleaned in a small clipper seed cleaner.

Cultural Practices 

On October 27, 2006, 50 lb phosphorus (P)/acre and 2 lb zinc (Zn)/acre were injected through 

the drip tape to all plots of Eriogonum umbellatum. On November 17, 2006, November 9, 2007, 

and April 15, 2008, all plots of Eriogonum umbellatum had Prowl® at 1 lb ai/acre broadcast on 

the soil surface for weed control. On March18, 2009, Prowl at 1 lb ai/acre and Volunteer® at 8 

oz/acre were broadcast on all Eriogonum umbellatum plots for weed control. On December 4, 

2009 and November 17, 2010, Prowl at 1 lb ai/acre was broadcast on all plots of Eriogonum 

umbellatum. On November 9, 2011 and November 7, 2012 Prowl at 1 lb ai/acre was broadcast 
PLANT MATERIALS AND CULTURAL PRACTICES

120

on all plots of both species. On April 3, 2013, Select Max at 32 oz/acre was broadcast for grass 

weed control on all plots of Eriogonum umbellatum. On February 26, 2014, Prowl at 1 lb ai/acre 

and Select Max at 32 oz/acre were broadcast on all plots of both species. On March 13, 2015, 

Prowl at 1 lb ai/acre was broadcast on all plots of both species. In addition to herbicides, weeds 

were controlled with hand weeding as necessary.

Table 1. Eriogonum umbellatum and Eriogonum heracleoides flowering, irrigation, and seed 

harvest dates by species in 2006-2015. Malheur Experiment Station, Oregon State University, 

Ontario, OR.

Flowering dates Irrigation dates

Species Year Start Peak End Start End Harvest

Eriogonum umbellatum 2006 19-May 20-Jul 19-May 30-Jun 3-Aug

2007 25-May 25-Jul 2-May 24-Jun 31-Jul

2008 5-Jun 19-Jun 20-Jul 15-May 24-Jun 24-Jul

2009 31-May 15-Jul 19-May 24-Jun 28-Jul

2010 4-Jun 12-19 Jun 15-Jul 28-May 8-Jul 27-Jul

2011 8-Jun 30-Jun 20-Jul 20-May 5-Jul 1-Aug

2012 30-May 20-Jun 4-Jul 30-May 11-Jul 24-Jul

2013 8-May 27-May 27-Jun 8-May 19-Jun 9-Jul

2014 20-May 4-Jun 1-Jul 13-May 24-Jun 10-Jul

2015 13-May 26-May 25-Jun 29-Apr 10-Jun 2-Jul

Eriogonum heracleoides 2011 26-May 10-Jun 8-Jul 27-May 6-Jul 1-Aug

2012 23-May 30-May 25-Jun 11-May 21-Jun 16-Jul

2013 29-Apr 13-May 10-Jun 24-Apr 5-Jun 1-Jul

2014 1-May 20-May 12-Jun 29-Apr 10-Jun 3-Jul

2015 24-Apr 5-May 17-Jun 15-Apr 27-May 24-Jun

Results and Discussion

Precipitation from January through June in 2009, 2012, and 2014 was close to the average of 5.8 

inches (Table 2). Precipitation from January through June in 2006, 2010, and 2011 was higher 

than the average of 5.8 inches. Precipitation from January through June in 2007, 2008, 2013, and 

2015 was lower than the average of 5.8 inches. The accumulated growing degree-days (50-86° F) 

from January through June in 2006, 2007, 2013, 2014, and 2015 were higher than average (Table 

2). Both buckwheats flowered and were harvested earlier in 2013-2015 than in 2011-2012 (Table 

1), consistent with more early season growing degree days (Table 2).

Seed Yields

Eriogonum umbellatum, Sulfur-flower Buckwheat

In 2006, seed yield of Eriogonum umbellatum increased with increasing water application, up to 

8 inches, the highest amount tested (Tables 3 and 4). In 2007-2009 seed yield showed a quadratic 

response to irrigation rate. Seed yields were maximized by 8.1 inches, 7.2 inches, and 6.9 inches 

of water applied in 2007, 2008, and 2009, respectively. In 2010, there was no significant 

difference in yield between the irrigation treatments. In 2011, seed yield was highest with no 

irrigation. The 2010 and 2011 seasons had unusually cool (Table 2, Fig. 2) and wet weather (Fig. 

2). The accumulated precipitation in April through June of 2010 and 2011 was the highest over 
PLANT MATERIALS AND CULTURAL PRACTICES

121

the years of the trial (Table 2). The relatively high seed yield of E. umbellatum in the nonirrigated treatment in 2010 and 2011 seemed to be related to the high spring precipitation. The 

negative effect of irrigation on seed yield in 2011 might have been related to the presence of rust. 

Irrigation could have exacerbated the rust and resulted in lower yields. In 2012, seed yield of 

Eriogonum umbellatum increased with increasing water application, up to 8 inches, the highest 

amount tested. In 2013 and 2014, seed yields showed quadratic responses to irrigation rate. Seed 

yield was maximized by 5.7 inches and by 5.3 inches of water applied in 2013 and 2014, 

respectively. In 2015, seed yields were not responsive to irrigation. Averaged over 10 years, seed 

yield of E. umbellatum showed a quadratic response to irrigation rate with the highest yield 

achieved with 6.5 inches of water applied. 

Eriogonum heracleoides, Parsnip-flower Buckwheat

In 2013, seed yields showed a quadratic response to irrigation with a maximum seed yield at 4.9 

inches of water applied. Seed yields did not respond to irrigation in 2011, 2012, 2014, and 2015 

(Tables 3 and 4). Averaged over 5 years, seed yield of E. heracleoides showed a quadratic 

response to irrigation rate with the highest yield achieved with 5.2 inches of water applied. Seed 

yields peaked in 2013 and have declined over the last two years, possibly due to loss of stand. 

Conclusions

The total irrigation requirements for these arid-land species were low and varied by species. 

Eriogonum heracleoides only responded to irrigation in 2013, a drier than average year. In the 

other years, natural rainfall was sufficient to maximize seed production in the absence of weed 

competition. Seed yield of E. umbellatum responded to irrigation in 7 of the 10 years, with 

quadratic responses to irrigation rate varying from 0 to 8 inches, depending on year. Buckwheat 

flowering and harvests have been earlier in 2013-2015, probably due to warmer weather.

Table 2. Early season precipitation and growing degree-days at the Malheur 

Experiment Station, Ontario, OR, 2006-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2006 9 3.1 1273

2007 3.1 1.9 1406

2008 2.9 1.2 1087

2009 5.8 3.9 1207

2010 8.3 4.3 971

2011 8.3 3.9 856

2012 5.8 2.3 1228

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.
PLANT MATERIALS AND CULTURAL PRACTICES

122

Table 3. Eriogonum umbellatum and Eriogonum heracleoides seed yield in response 

to irrigation rate (inches/season) in 2006 through 2015. Malheur Experiment Station, 

Oregon State University, Ontario, OR.

Irrigation rate

Species Year 0 inches 4 inches 8 inches

LSD 

(0.05)

----------------- lb/acre ----------------

Eriogonum umbellatum 2006 155.3 214.4 371.6 92.9

2007 79.6 164.8 193.8 79.8

2008 121.3 221.5 245.2 51.7

2009 132.3 223 240.1 67.4

2010 252.9 260.3 208.8 NSa

2011 248.7 136.9 121 90.9

2012 61.2 153.2 185.4 84.4

2013 113.2 230.1 219.8 77.5

2014 257 441.8 402.7 82.9

2015 136.4 124.4 90.7 NS

Average 158.8 217.4 224.1 28.5

Eriogonum heracleoides 2011 55.2 71.6 49 NSa

2012 252.3 316.8 266.4 NS

2013 287.4 516.9 431.7 103.2

2014 297.6 345.2 270.8 NS

2015 83.6 148.2 122.3 NS

Average 169.3 275.8 247.8 58.9

a Not significant. There was no statistically significant trend in seed yield in response to 

amount of irrigation.
PLANT MATERIALS AND CULTURAL PRACTICES

123

Table 4. Regression analysis for Eriogonum umbellatum and Eriogonum heracleoides 

seed yield (y) in response to irrigation (x) (inches/season) using the equation y = a + bx + 

cx2. For the quadratic equations, the amount of irrigation that resulted in maximum yield 

was calculated using the formula: -b/2c, where b is the linear parameter and c is the 

quadratic parameter. Malheur Experiment Station, Oregon State University, Ontario, OR. 

Eriogonum umbellatum Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2006 137.9 27.8 0.68 0.01 360 8

2007 79.6 28.3 -1.8 0.69 0.05 194 8.1

2008 121.3 34.6 -2.4 0.73 0.01 246 7.2

2009 132.3 31.9 -2.3 0.6 0.05 243 6.9

2010 252.9 9.2 -1.8 0.08 NSa

2011 232.7 -16 0.58 0.01 233 0

2012 61.2 30.5 -1.9 0.65 0.01 185 8.1

2013 113.2 45.2 -4 0.62 0.05 241 5.7

2014 257 74.2 -7 0.76 0.01 454 5.3

2015 140.0 -5.7 0.11 NS

Average 158.8 21.2 -1.6 0.75 0.01 228 6.5

Eriogonum heracleoides Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2011 61.7 -0.8 0.01 NS

2012 271.5 1.8 0.01 NS

2013 287.4 96.7 -9.8 0.64 0.05 525 4.9

2014 297.6 27.2 -3.8 0.08 NS

2015 83.6 27.5 -2.8 0.29 NS

Average 169.3 43.4 -4.2 0.71 0.01 282 5.2

a Not significant. There was no statistically significant trend in seed yield in response to amount of 

irrigation.

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant 

No. 2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National 

Institute of Food and Agriculture.
PLANT MATERIALS AND CULTURAL PRACTICES

124

2. Irrigation Requirements for Seed Production of Five Lomatium Species in a Semi-Arid 

Environment

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, and Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR, 2015 

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID

Summary

Lomatium species are important components in the rangelands of the Intermountain West. 

Relatively little is known about the cultural practices necessary to produce Lomatium seed for 

use in rangeland restoration activities. The seed yield response to four biweekly irrigations 

applying either 0, 1 inch of water, or 2 inches of water (total of 0, 4 inches, or 8 inches/season) 

was evaluated for four Lomatium species over multiple years starting in 2007. Over seven seed 

production seasons, Lomatium dissectum (fernleaf biscuitroot) seed yield was maximized by 5 to 

6 inches of water applied per season in cooler, wetter years and by 8 inches of water applied per 

season in warmer, drier years. Over nine seed production seasons, Lomatium grayi (Gray’s 

biscuitroot) seed yield was maximized by 0 to 5 inches of water applied per season in cooler, 

wetter years and by 5 to 8 inches of water applied per season in warmer, drier years. Over nine 

seed production seasons, Lomatium triternatum (Nineleaf biscuitroot) seed yield was maximized 

by 4 to 8 inches of water applied per season in cooler, wetter years and by 8 inches of water 

applied per season in warmer, drier years. Over four seed production seasons, Lomatium 

nudicaule (barestem biscuitroot) seed yield did not respond to irrigation. In the two seed 

production seasons observed, seed yield of Lomatium suksdorfii (Suksdorf’s desert parsley)

responded to irrigation in 2015. 

Introduction

Native wildflower seed is needed to restore rangelands of the Intermountain West. Commercial 

seed production is necessary to provide the quantity of seed needed for restoration efforts. A 

major limitation to economically viable commercial production of native wildflower (forb) seed 

is stable and consistent seed production over years. 

In native rangelands, the natural variations in spring rainfall and soil moisture result in highly 

unpredictable water stress at flowering, seed set, and seed development, which for other seed 

crops is known to compromise seed yield and quality. 

Native wildflower plants are not well adapted to croplands. They often are not competitive with 

crop weeds in cultivated fields. Poor competitiveness with weeds could also limit wildflower 

seed production. Supplemental water can be provided by sprinkler or furrow irrigation systems, 

but these irrigation systems risk further encouraging weeds. Sprinkler and furrow irrigation can 

lead to the loss of plant stand and seed production due to fungal pathogens. Burying drip tapes at 

12-inch depth and avoiding wetting the soil surface could help to assure flowering and seed set 
PLANT MATERIALS AND CULTURAL PRACTICES

125

without undue encouragement of weeds or opportunistic diseases. The trials reported here tested 

the effects of three low rates of irrigation on the seed yield of five Lomatium species (Table 1). 

Subsurface drip irrigation systems were tested for native seed production because they have two 

potential strategic advantages: a) low water use, and b) the buried drip tape provides water to the 

plants at depth, precluding most irrigation induced stimulation of weed seed germination on the 

soil surface and keeping water away from native plant tissues that are not adapted to a wet 

environment. 

Table 1. Lomatium species planted in the drip irrigation trials at the Malheur Experiment 

Station, Oregon State University, Ontario, OR.

Species Common names

Lomatium dissectum Fernleaf biscuitroot

Lomatium triternatum Nineleaf biscuitroot, nineleaf desert parsley

Lomatium grayi Gray’s biscuitroot, Gray’s lomatium

Lomatium nudicaule Barestem biscuitroot, Barestem lomatium

Lomatium suksdorfii Suksdorf’s desert parsley

Materials and Methods

Plant Establishment

Seed of Lomatium dissectum, L. grayi and L. triternatum was received in late November in 2004 

from the Rocky Mountain Research Station (Boise, ID). The plan was to plant the seed in the fall 

of 2004, but due to excessive rainfall in October, ground preparation was not completed and 

planting was postponed to early 2005. To try to ensure germination, the seed was submitted to 

cold stratification. The seed was soaked overnight in distilled water on January 26, 2005, after 

which the water was drained and the seed soaked for 20 min in a 10% by volume solution of 

13% bleach in distilled water. The water was drained and the seed was placed in thin layers in 

plastic containers. The plastic containers had lids with holes drilled in them to allow air 

movement. These containers were placed in a cooler set at approximately 34° F. Every few days 

the seed was mixed and, if necessary, distilled water added to maintain seed moisture. In late 

February, seed of Lomatium grayi and L. triternatum had started to sprout. 

In late February 2005, drip tape (T-Tape TSX 515-16-340) was buried at 12-inch depth between 

two 30-inch rows of a Nyssa silt loam with a pH of 8.3 and 1.1% organic matter. The drip tape 

was buried in alternating inter-row spaces (5 ft apart). The flow rate for the drip tape was 0.34 

gal/min/100 ft at 8 psi with emitters spaced 16 inches apart, resulting in a water application rate 

of 0.066 inch/hour.

On March 3, 2005, seed of the three species in Table 1 was planted in 30-inch rows using a 

custom-made plot grain drill with disc openers. All seed was planted at 20-30 seeds/ft of row. 

The seed was planted at 0.5-inch depth. The trial was irrigated from March 4 to April 29 with a 

minisprinkler system (R10 Turbo Rotator, Nelson Irrigation Corp., Walla Walla, WA) for even 

stand establishment. Risers were spaced 25 ft apart along the flexible polyethylene hose laterals 

that were spaced 30 ft apart and the water application rate was 0.10 inch/hour. A total of 1.72 

inches of water was applied with the minisprinkler system. Lomatium triternatum, and L. grayi

started emerging on March 29. Beginning on June 24, the field was irrigated with the drip 

irrigation system. A total of 3.73 inches of water was applied with the drip system from June 24 

to July 7. The field was not irrigated further in 2005. 
PLANT MATERIALS AND CULTURAL PRACTICES

126

Plant stands for Lomatium triternatum, and L. grayi were uneven. Lomatium dissectum did not 

emerge. None of the species flowered in 2005. In early October, 2005 more seed was received 

from the Rocky Mountain Research Station for replanting. The plots had the entire row lengths 

replanted using the planter on October 26, 2005. In the spring of 2006, the plant stands of the 

replanted species were excellent. 

On November 25, 2009 seed of L. nudicaule, L. suksdorfii, and three selections of L. dissectum 

(LODI 38, LODI 41, and seed from near Riggins, ID) was planted in 30-inch rows using a 

custom-made plot grain drill with disk openers. All seed was planted on the soil surface at 20-30 

seeds/ft of row. After planting, sawdust was applied in a narrow band over the seed row at 0.26 

oz/ft of row (558 lb/acre). Following planting and sawdust application, the beds were covered 

with row cover. The row cover (N-sulate, DeWitt Co., Inc., Sikeston, MO) covered four rows 

(two beds) and was applied with a mechanical plastic mulch layer. The field was irrigated for 24 

hours on December 2, 2009 due to very dry soil conditions.

Irrigation for Seed Production 

In April, 2006 (April 2010 for the species and selections planted in 2009) each planted strip of 

each species was divided into plots 30 ft long. Each plot contained four rows of each species. 

The experimental design for each species was a randomized complete block with four replicates. 

The three treatments were a non-irrigated check, 1 inch of water applied per irrigation, and 2 

inches of water applied per irrigation. Each treatment received 4 irrigations that were applied 

approximately every 2 weeks starting with flowering. The amount of water applied to each 

treatment was calculated by the length of time necessary to deliver 1 or 2 inches through the drip 

system. Irrigations were regulated with a controller and solenoid valves. After each irrigation, the 

amount of water applied was read on a water meter and recorded to ensure correct water 

applications. 

Irrigation dates are found in Table 2. In 2007, irrigation treatments were inadvertently continued 

after the fourth irrigation. Irrigation treatments for all species were continued until the last 

irrigation on June 24, 2007. 

Flowering, Harvesting, and Seed Cleaning 

Flowering dates for each species were recorded (Table 2). Each year, the middle two rows of 

each plot were harvested manually when seed of each species was mature (Table 2). Seed was 

cleaned manually. 

Cultural Practices in 2006

On October 27, 2006, 50 lb phosphorus (P)/acre and 2 lb zinc (Zn)/acre were injected through 

the drip tape to all plots. On November 11, 100 lb nitrogen (N)/acre as urea was broadcast to all 

plots. On November 17, all plots had Prowl® at 1 lb ai/acre broadcast on the soil surface. 

Irrigations for all species were initiated on May 19 and terminated on June 30. 

Cultural Practices in 2007

Irrigations for each species were initiated and terminated on different dates (Table 2). 
PLANT MATERIALS AND CULTURAL PRACTICES

127

Cultural Practices in 2008

On November 9, 2007 and on April 15, 2008, Prowl at 1 lb ai/acre was broadcast on all plots for 

weed control. 

Cultural Practices in 2009

On March18, Prowl at 1 lb ai/acre and Volunteer® at 8 oz/acre were broadcast on all plots for 

weed control. On April 9, 50 lb N/acre and 10 lb P/acre were applied through the drip irrigation 

system to the three Lomatium spp. 

On December 4, 2009, Prowl at 1 lb ai/acre was broadcast for weed control on all plots. 

Cultural Practices in 2010

On November 17, Prowl at 1 lb ai/acre was broadcast on all plots for weed control. 

Cultural Practices in 2011

On May 3, 2011, 50 lb N/acre was applied to all Lomatium spp. plots as Uran (urea ammonium 

nitrate) injected through the drip tape. On November 9, Prowl at 1 lb ai/acre was broadcast on all 

plots for weed control. 

Cultural Practices in 2012

Iron deficiency symptoms were prevalent in 2012. Liquid fertilizer was injected containing 50 lb 

N/acre, 10 lb P/acre, and 0.3 lb iron (Fe)/acre using a brief pulse of water through the drip 

irrigation system to all plots on April 13. On November 7, Prowl at 1 lb ai/acre was broadcast on 

all plots for weed control. 

Cultural Practices in 2013

Liquid fertilizer was injected containing 20 lb N/acre, 25 lb P/acre, and 0.3 lb Fe/acre using a 

brief pulse of water through the drip irrigation system to all plots on March 29. On April 3, 

Select Max at 32 oz/acre was broadcast for grass weed control on all plots. 

Cultural Practices in 2014

On February 26, Prowl at 1 lb ai/acre and Select Max at 32 oz/acre were broadcast on all plots 

for weed control. Liquid fertilizer was injected containing 20 lb N/acre, 25 lb P/acre, and 0.3 lb 

Fe/acre using a brief pulse of water through the drip irrigation system to all plots on April 2. 

Cultural Practices in 2015

On March 13, Prowl at 1 lb ai/acre was broadcast on all plots for weed control. Liquid fertilizer 

was injected containing 20 lb N/acre, 25 lb P/acre, and 0.3 lb Fe/acre using a brief pulse of water 

through the drip irrigation system to all plots on April 15. 
PLANT MATERIALS AND CULTURAL PRACTICES

128

Table 2. Lomatium flowering, irrigation, and seed harvest dates by species in 2006-2015. 

Malheur Experiment Station, Oregon State University, Ontario, OR. 

Flowering Irrigation

Species Year Start Peak End Start End Harvest

Lomatium dissectum 2006 19-May 30-Jun

2007 5-Apr 24-Jun

2008 10-Apr 29-May

2009 10-Apr 7-May 20-Apr 28-May 16-Jun

2010 25-Apr 20-May 15-Apr 28-May 21-Jun

2011 8-Apr 25-Apr 10-May 21-Apr 7-Jun 20-Jun

2012 9-Apr 16-Apr 16-May 13-Apr 24-May 4-Jun

2013 10-Apr 25-Apr 4-Apr 16-May 4-Jun

2014 28-Mar 21-Apr 7-Apr 20-May 2-Jun

2015 1-Apr 24-Apr 1-Apr 13-May 26-May (0 in), 1-Jun (4, 8 in)

Lomatium grayi 2006 19-May 30-Jun

2007 5-Apr 10-May 5-Apr 24-Jun 30-May, 29-Jun

2008 25-Mar 15-May 10-Apr 29-May 30-May, 19-Jun

2009 10-Mar 7-May 20-Apr 28-May 16-Jun

2010 15-Mar 15-May 15-Apr 28-May 22-Jun

2011 1-Apr 25-Apr 13-May 21-Apr 7-Jun 22-Jun

2012 15-Mar 25-Apr 16-May 13-Apr 24-May 14-Jun

2013 15-Mar 30-Apr 4-Apr 16-May 10-Jun

2014 28-Mar 2-May 7-Apr 20-May 10-Jun

2015 1-Mar 28-Apr 1-Apr 13-May 1-Jun

Lomatium triternatum 2006 19-May 30-Jun

2007 25-Apr 1-Jun 5-Apr 24-Jun 29-Jun, 16-Jul

2008 25-Apr 5-Jun 10-Apr 29-May 3-Jul

2009 10-Apr 7-May 1-Jun 20-Apr 28-May 26-Jun

2010 25-Apr 15-Jun 15-Apr 28-May 22-Jul

2011 30-Apr 23-May 15-Jun 21-Apr 7-Jun 26-Jul

2012 12-Apr 17-May 6-Jun 13-Apr 24-May 21-Jun

2013 18-Apr 10-May 4-Apr 16-May 4-Jun

2014 7-Apr 29-Apr 2-May 7-Apr 20-May 4-Jun

2015 10-Apr 28-Apr 20-May 1-Apr 13-May 7-Jun (0 in), 15-Jun (4, 8 in)

Lomatium nudicaule 2011 No flowering

2012 12-Apr 1-May 30-May 18-Apr 30-May 22-Jun

2013 11-Apr 20-May 12-Apr 22-May 10-Jun

2014 7-Apr 13-May 7-Apr 20-May 16-Jun

2015 25-Mar 5-May 1-Apr 13-May 8-Jun

Lomatium suksdorfii 2013 18-Apr 23-May

2014 15-Apr 20-May 7-Apr 20-May 30-Jun

2015 3-Apr 27-Apr 10-May 1-Apr 13-May 23-Jun
PLANT MATERIALS AND CULTURAL PRACTICES

129

Results and Discussion

Precipitation from January through June in 2009, 2012, and 2014 was close to the average of 5.8 

inches (Table 3). Precipitation from January through June in 2006, 2010, and 2011 was higher 

than the average of 5.8 inches. Precipitation from January through June in 2007, 2008, 2013, and 

2015 was lower than the average of 5.8 inches The accumulated growing degree-days (50-86° F) 

from January through June in 2006, 2007, 2013, 2014, and 2015 were higher than average (Table 

2). The high accumulated growing degree days in 2015 probably caused early harvest dates 

(Table 2).

Table 3. Early season precipitation and growing degree-days at the 

Malheur Experiment Station, Ontario, OR, 2006-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2006 9 3.1 1273

2007 3.1 1.9 1406

2008 2.9 1.2 1087

2009 5.8 3.9 1207

2010 8.3 4.3 971

2011 8.3 3.9 856

2012 5.8 2.3 1228

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.

Flowering and Seed Set

Lomatium grayi and L. triternatum started flowering and producing seed in 2007 (2nd year after 

fall planting in 2005, Tables 2 and 4). Lomatium dissectum started flowering and producing seed 

in 2009 (4th year after fall planting in 2005). Lomatium nudicaule started flowering and produced 

seed in 2012 (3rd year after fall planting in 2009). Lomatium suksdorfii started flowering and 

produced seed in 2013 (4th year after fall planting in 2009).

Seed Yields

Lomatium dissectum, Fernleaf Biscuit Root

Lomatium dissectum had very little vegetative growth during 2006-2008, and produced only very 

few flowers in 2008. All the Lomatium species tested were affected by Alternaria fungus, but the 

infection was greatest on the L. dissectum selection planted in this trial. This infection delayed L. 

dissectum plant development. In 2009, vegetative growth and flowering for L. dissectum were 

improved. 

Seed yield of L. dissectum had linear responses to irrigation rate in 2009 (Tables 4 and 6). Seed 

yield with the 4-inch irrigation rate was significantly higher than with the non-irrigated check, 

but the 8-inch irrigation rate did not result in a significant increase above the 4-inch rate. In 2010 

and 2011, seed yields of L. dissectum showed a quadratic response to irrigation rate. Seed yields 

were estimated to be maximized by 5.4 and 5.1 inches of applied water in 2010 and 2011, 

respectively. In 2012, seed yields of L. dissectum were not responsive to irrigation. In 2013, 

2014, and 2015 seed yield increased linearly with increasing irrigation rate up to 8 inches, the 
PLANT MATERIALS AND CULTURAL PRACTICES

130

highest amount applied. Averaged over the 7 years, seed yield showed a quadratic response to 

irrigation rate and was estimated to be maximized at 930 lb/acre/year by applying 6.5 inches of 

applied water.

Lomatium dissectum Riggins Selection

The Riggins selection L. dissectum started flowering in 2013, but only in small amounts. Seed 

yields of Riggins selection L. dissectum showed a quadratic response to irrigation rate in 2014 

(Tables 5 and 7). Seed yields were estimated to be maximized by 4.8 inches of applied water in 

2014. Seed was inadvertently not harvested in 2015.

Lomatium dissectum Selections 38 and 41

L. dissectum 38 and 41started flowering in 2013, but only in small amounts. Seed yields of L. 

dissectum 38 were not responsive to irrigation in 2014 and 2015 (Tables 5 and 7). Seed yields of 

L. dissectum 41 were not responsive to irrigation in 2014. In 2015, seed yields of L. dissectum 41 

showed a quadratic response to irrigation rate (Tables 5 and 7). Seed yields of L. dissectum 41 

were estimated to be maximized by 4.9 inches of applied water in 2015.

Lomatium grayi, Gray’s Biscuitroot

Lomatium grayi showed a trend for increasing seed yield with increasing irrigation rate most 

years (Tables 4 and 6). The highest irrigation rate resulted in significantly higher seed yield than 

the non-irrigated check in six of the last eight years. Seed yields of L. grayi were substantially 

higher in 2008 and 2009. 

In 2008, seed yields of L. grayi showed a quadratic response to irrigation rate. Seed yields were 

estimated to be maximized by 6.9 inches of water applied in 2008. In 2009, seed yield showed a 

linear response to irrigation rate. Seed yield with the 4-inch irrigation rate was significantly 

higher than in the non-irrigated check, but the 8-inch irrigation rate did not result in a significant 

increase above the 4-inch rate. 

In 2010, seed yield was not responsive to irrigation, possibly caused by the unusually wet spring 

of 2010. Rodent damage was a further complicating factor in 2010 that compromised seed yields. 

Extensive rodent (vole) damage occurred over the 2009-2010 winter. The affected areas were 

transplanted with 3-year-old L. grayi plants from an adjacent area in the spring of 2010. To 

reduce their attractiveness to voles, the plants were mowed after becoming dormant in early fall 

of 2010 and in each subsequent year. 

In 2011, seed yield again did not respond to irrigation. The spring of 2011 was unusually cool 

and wet. 

In 2012, seed yields of L. grayi showed a quadratic response to irrigation rate, with a maximum 

seed yield at 5.5 inches of applied water. 

In 2013, seed yield increased linearly with increasing water application, up to 8 inches, the 

highest amount applied. 

In 2014, seed yields of L. grayi showed a quadratic response to irrigation rate, with a calculated 

maximum seed yield of 1477 lb/acre at 5.3 inches of applied water. 
PLANT MATERIALS AND CULTURAL PRACTICES

131

In 2015, seed yields of L. grayi showed a quadratic response to irrigation rate, with a calculated 

maximum seed yield of 579 lb/acre at 4.3 inches of applied water.

Over 9 years, seed yield of L. grayi was estimated to be maximized at 797 lb/acre/year by 5.2 

inches of applied water. Most appropriately, irrigation probably should be variable according to 

precipitation.

Lomatium nudicaule, Barestem Biscuitroot

Seed yields did not respond to irrigation in the 4 years seed was harvested (Tables 4 and 6). Seed 

yields in the range of 350 to 700 lb/acre per year were harvested in 2013, 2014, and 2015, the 

fourth, fifth, and sixth year after planting.

Lomatium triternatum, Nineleaf Biscuitroot

Lomatium triternatum showed a trend for increasing seed yield with increasing irrigation rate 

most years (Tables 4 and 6). The highest irrigation rate resulted in significantly higher seed yield 

than the non-irrigated check in seven of the last eight years. Seed yields of L. triternatum were 

substantially higher in 2008-2011. 

In 2008–2011 seed yields of L. triternatum showed a quadratic response to irrigation rate. Seed 

yields were estimated to be maximized by 8.4, 5.4, 7.8, and 4.1 inches of water applied in 2008, 

2009, 2010, and 2011, respectively. 

Each year from 2012 through 2015 seed yield increased linearly with increasing water applied up 

to the highest amount of water applied, 8 inches. 

Over 9 years, seed yield of L. triternatum was estimated to be maximized at 1273 lb/acre/year at 

7.7 inches of applied water. 

Lomatium suksdorfii, Suksdorfii Desert Parsley

Lomatium suksdorfii started flowering in 2013, but only in small amounts. Seed yields of L. 

suksdorfii were not responsive to irrigation in 2014 (Tables 5 and 7). In 2015, seed yield 

increased linearly with increasing water applied up to the highest amount of water applied, 8 

inches. 

Management Applications

This report describes irrigation practices that can be immediately implemented by seed growers. 

Multi-year summaries of research findings are found in Tables 4-8.

Conclusions

The Lomatium species were relatively slow to produce ample seed. Lomatium grayi and L. 

triternatum had reasonable seed yields starting in the second year. L. dissectum and L. nudicaule

were productive in their fourth year, while L. suksdorfii was only moderately productive in the 

fifth year after planting. The delayed maturity affects the cost of seed production, but these 

species have proven to be strong perennials, especially when protected from rodent damage.

Due to the arid environment, supplemental irrigation may often be required for successful 

flowering and seed set because soil water reserves may be exhausted before seed formation. The 

total irrigation requirements for these arid-land species were low and varied by species (Table 8). 

Lomatium nudicaule did not respond to irrigation in these trials. Natural rainfall was sufficient to 
PLANT MATERIALS AND CULTURAL PRACTICES

132

maximize seed production for L. nudicaule in the absence of weed competition. Lomatium 

dissectum required approximately 6 inches of irrigation. Lomatium grayi and L. triternatum

responded quadratically to irrigation with the optimum varying by year. 

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant 

No. 2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National 

Institute of Food and Agriculture.
PLANT MATERIALS AND CULTURAL PRACTICES

Table 4. Seed yield response to irrigation rate (inches/season) for four Lomatium species in 2006 through 2015. Malheur 

Experiment Station, Oregon State University, Ontario, OR.

Irrigation rate Irrigation rate

Species Year 0 inches 4 inches 8 inches LSD (0.05) Species Year 0 inches 4 inches 8 inches LSD (0.05)

Lomatium dissectum ---------- lb/acre ---------- Lomatium grayi ---------- lb/acre ----------

2006 ---- no flowering ---- 2006 ---- no flowering ----

2007 ---- no flowering ---- 2007 36.1 88.3 131.9 77.7b

2008 - very little flowering - 2008 393.3 1287 1444.9 141

2009 50.6 320.5 327.8 196.4b 2009 359.9 579.8 686.5 208.4

2010 265.8 543.8 499.6 199.6 2010 1035.7 1143.5 704.8 NS

2011 567.5 1342.8 1113.8 180.9 2011 570.3 572.7 347.6 NS

2012 388.1 460.3 444.4 NS 2012 231.9 404.4 377.3 107.4

2013 527.8 959.8 1166.7 282.4 2013 596.7 933.4 1036.3 NS

2014 353.4 978.9 1368.3 353.9 2014 533.1 1418.1 1241.3 672

2015 591.2 1094.7 1376.0 348.7 2015 186.4 576.7 297.6 213.9

7-year average 392.0 851.3 899.5 95.1 9-year average 445.1 778.2 696.5 227.2

Irrigation rate Irrigation rate

Species Year 0 inches 4 inches 8 inches LSD (0.05) Species Year 0 inches 4 inches 8 inches LSD (0.05)

Lomatium nudicaule ---------- lb/acre ---------- Lomatium triternatum ---------- lb/acre ----------

2006 ---- no flowering ----

2007 2.3 17.5 26.7 16.9b

2008 195.3 1060.9 1386.9 410

2009 181.6 780.1 676.1 177

2010 ---- no flowering ---- 2010 1637.2 2829.6 3194.6 309.4

2011 ---- no flowering ---- 2011 1982.9 2624.5 2028.1 502.3b

2012 53.8 123.8 61.1 NS 2012 238.7 603 733.2 323.9

2013 357.6 499.1 544 NS 2013 153.7 734.4 1050.9 425

2014 701.3 655.6 590.9 NS 2014 240.6 897.1 1496.7 157

2015 430.6 406.1 309.3 NS 2015 403.2 440.8 954.9 446.6

4-year average 376.3 421.1 385.8 NS 9-year average 559.5 1109.8 1271.0 156.7

bLSD (0.10)
PLANT MATERIALS AND CULTURAL PRACTICES

134

Table 5. Seed yield response to irrigation rate (inches/season) for two Lomatium

species in 2014 and 2015. Malheur Experiment Station, Oregon State University, 

Ontario, OR.

Irrigation rate

Species Year 0 inches 4 inches 8 inches LSD (0.05)

Lomatium dissectum Riggins selection 2014 276.8 497.7 398.4 163

Lomatium dissectum selection 38

2014 281.9 356.4 227.1 NS

2015 865.1 820.9 774.6 NS

2-year average 573.5 588.6 432.9 NS

Lomatium dissectum selection 41

2014 222.2 262.4 149.8 NS

2015 152.2 561.9 407.4 181.4

2-year average 187.2 412.1 278.6 167.4

Lomatium suksdorfii

2014 162.6 180.0 139.8 NS

2015 829.6 1103.9 1832.0 750.2

2-year average 496.1 642.0 1208.6 NS
PLANT MATERIALS AND CULTURAL PRACTICES

135

Table 6. Regression analysis for native wildflower seed yield (y) in response to irrigation (x) 

(inches/season) using the equation y = a + bx + cx2 in 2006 - 2015, and 2- to 9-year averages. For the 

quadratic equations, the amount of irrigation that resulted in maximum yield was calculated using the 

formula: -b/2c, where b is the linear parameter and c is the quadratic parameter. Malheur Experiment 

Station, Oregon State University, Ontario, OR.

Lomatium dissectum

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2009 86.4 34.6 0.31 0.10 363 8.0

2010 265.8 109.8 -10.1 0.68 0.01 564 5.4

2011 567.5 319.3 -31.4 0.86 0.001 1379 5.1

2012 402.7 7.0 0.04 NS

2013 565.3 79.9 0.65 0.01 1204 8.0

2014 392.7 126.9 0.82 0.001 1408 8.0

2015 628.2 98.1 0.76 0.001 1413 8.0

Average 392.0 166.2 -12.8 0.94 0.001 930 6.5

Lomatium grayi

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2007 37.5 12.0 0.26 0.10 134 8.0

2008 393.3 315.4 -23.0 0.93 0.001 1475 6.9

2009 378.7 40.8 0.38 0.05 705 8.0

2010 1035.7 95.3 -17.1 0.22 NS

2011 608.2 -27.8 0.07 NS

2012 231.9 68.1 -6.2 0.66 0.01 419 5.5

2013 635.6 55.0 0.25 0.10 1075 8.0

2014 533.1 354.0 -33.2 0.64 0.05 1477 5.3

2015 186.4 181.3 -20.9 0.71 0.01 579 4.3

Average 445.1 135.1 -13.0 0.59 0.05 797 5.2

Lomatium nudicaule

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2012 75.9 0.9 0.01 NS

2013 373.7 23.3 0.1 NS

2014 704.5 -13.8 0.08 NS

2015 442.7 -15.2 0.15 NS

Average 399.2 -1.2 0.01 NS

Lomatium triternatum

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2007 3.3 3.1 0.52 0.01 28 8.0

2008 195.3 283.9 -16.9 0.77 0.01 1388 8.4

2009 181.6 237.4 -22.0 0.83 0.001 822 5.4

2010 1637.2 401.5 -25.9 0.83 0.001 3193 7.8

2011 1982.9 315.1 -38.7 0.45 0.10 2624 4.1

2012 277.8 61.8 0.49 0.05 772 8.0

2013 197.7 112.2 0.66 0.01 1095 8.0

2014 249.6 157.4 0.97 0.001 1509 8.0

2015 323.8 69.0 0.51 0.01 875 8.0

Average 559.5 186.2 -12.2 0.85 0.001 1272 7.7

a Not significant. There was no statistically significant trend in seed yield in response to the amount of irrigation. 
PLANT MATERIALS AND CULTURAL PRACTICES

136

Table 7. Regression analysis for seed yield response to irrigation rate (inches/season) in 2014 and 2015 for 

Lomatium suksdorfii and three selections of L. dissectum planted in 2009. For the quadratic equations, the 

amount of irrigation that resulted in maximum yield was calculated using the formula: -b/2c, where b is the 

linear parameter and c is the quadratic parameter. Malheur Experiment Station, Oregon State University, 

Ontario, OR. 

Lomatium suksdorfii

Year intercept linear quadratic R

2 P

Maximum seed 

yield

Water applied for 

maximum yield

lb/acre inches/season

2014 162.6 11.5 -1.8 0.01 NS

2015 753.9 125.3 0.43 0.05 1756.4 8.0

Average 171.7 -2.5 0.01 NS

Lomatium dissectum 'Riggins'

Year intercept linear quadratic R

2 P

Maximum seed 

yield

Water applied for 

maximum yield

lb/acre inches/season

2014 276.8 95.2 -10 0.57 0.05 503.5 4.8

Lomatium dissectum '38'

Year intercept linear quadratic R

2 P

Maximum seed 

yield

Water applied for 

maximum yield

lb/acre inches/season

2014 281.9 44.1 -6.4 0.11 NS

2015 865.4 -11.3 0.01 NS

Average 573.5 25.1 -5.3381 0.11 NS

Lomatium dissectum '41'

Year intercept linear quadratic R

2 P

Maximum seed 

yield

Water applied for 

maximum yield

lb/acre inches/season

2014 222.2 29.1 -4.8 0.13 NS

2015 152.2 172.9 -17.6291 0.67 0.01 576.3 4.9

Average 187.2 101.0 -11.2012 0.43 0.1 415.1 4.5

Table 8. Amount of irrigation water for maximum Lomatium seed yield, years to seed set, and 

life span. A summary of multi-year research findings, Malheur Experiment Station, Oregon State 

University, Ontario, OR.

Species Optimum amount of irrigation

Years to first

seed set Life span

inches/season from fall planting years

Lomatium dissectum 5 in wet years, 8 in dry years 4 9+

Lomatium grayi 0 in wet years, 5 to 8 in dry years 2 9+

Lomatium nudicaule no response 3 4+

Lomatium triternatum average of 6.9 inches over 8 years 2 9+

Lomatium suksdorfii 8 inches (2015) 5 5+
PLANT MATERIALS AND CULTURAL PRACTICES

137

3. Irrigation Requirements for Seed Production of Five Native Penstemon Species in a SemiArid Environment

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, and Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR 

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID

Summary

Penstemon is an important wildflower genus in the Great Basin of the United States. Seed of 

Penstemon species are desired for rangeland restoration activities, but little cultural practice 

information is known for seed production of native penstemons. The seed yield response of five 

Penstemon species to four biweekly irrigations applying either 0, 1, or 2 inches of water (a total of 

0, 4, or 8 inches of water/season) was evaluated over multiple years. Penstemon acuminatus

(sharpleaf penstemon), Penstemon speciosus (royal penstemon), and Penstemon cyaneus (blue 

pentstemon) seed yields were maximized by 4 to 8 inches of water applied per season in warmer, 

drier years and were not responsive to irrigation in cooler, wetter years. Penstemon pachyphyllus

(thickleaf beardtongue) seed yields were maximized by 8 inches of water applied per season in 

warmer, drier years and were not responsive to irrigation in cooler, wetter years. In 6 years of 

testing, seed yields of Penstemon deustus (scabland penstemon) only responded to irrigation in 

2015, with 5.4 inches of water applied resulting in the highest yields.

Introduction

Native wildflower seed is needed to restore rangelands of the Intermountain West. Commercial seed 

production is necessary to provide the quantity of seed needed for restoration efforts. A major 

limitation to economically viable commercial production of native wildflower (forb) seed is stable 

and consistent seed productivity over years. 

In native rangelands, the natural variations in spring rainfall and soil moisture result in highly 

unpredictable water stress at flowering, seed set, and seed development, which for other seed crops 

is known to compromise seed yield and quality. 

Native wildflower plants are not well adapted to croplands. They often are not competitive with 

crop weeds in cultivated fields. Poor competitiveness with weeds could also limit wildflower seed 

production. Both sprinkler and furrow irrigation could provide supplemental water for seed 

production, but these irrigation systems risk further encouraging weeds. Also, sprinkler and furrow 

irrigation can lead to the loss of plant stand and seed production due to fungal pathogens. By 

burying drip tapes at 12-inch depth and avoiding wetting the soil surface, experiments were 

designed to assure flowering and seed set without undue encouragement of weeds or opportunistic 

diseases. The trials reported here tested the effects of three low rates of irrigation on the seed yield 

of five species of Penstemon native to the intermountain west (Table 1). 
PLANT MATERIALS AND CULTURAL PRACTICES

138

Table 1. Penstemon species planted in the drip irrigation trials at the Malheur 

Experiment Station, Oregon State University, Ontario, OR.

Species Common names

Penstemon acuminatus Sharpleaf penstemon, sand-dune penstemon

Penstemon cyaneus Blue penstemon

Penstemon deustus Scabland penstemon, hotrock penstemon

Penstemon pachyphyllus Thickleaf beardtongue

Penstemon speciosus Royal penstemon, sagebrush penstemon

Materials and Methods

Plant Establishment: Penstemon acuminatus, P. deustus, and P. speciosus

Seed of Penstemon acuminatus, P. deustus, and P. speciosus was received in late November in 2004 

from the Rocky Mountain Research Station (Boise, ID). The plan was to plant the seed in the fall of 

2004, but due to excessive rainfall in October, the ground preparation was not completed and 

planting was postponed to early 2005. To try to ensure germination, the seed was submitted to cold 

stratification. The seed was soaked overnight in distilled water on January 26, 2005, after which the 

water was drained and the seed soaked for 20 min in a 10% by volume solution of 13% bleach in 

distilled water. The water was drained and the seed was placed in thin layers in plastic containers. 

The plastic containers had lids with holes drilled in them to allow air movement. These containers 

were placed in a cooler set at approximately 34° F. Every few days the seed was mixed and, if 

necessary, distilled water added to maintain seed moisture. 

In late February 2005, drip tape (T-Tape TSX 515-16-340) was buried at 12-inch depth between 

two 30-inch rows of a Nyssa silt loam with a pH of 8.3 and 1.1 percent organic matter. The drip 

tape was buried in alternating inter-row spaces (5 ft apart). The flow rate for the drip tape was 0.34 

gal/min/100 ft at 8 psi with emitters spaced 16 inches apart, resulting in a water application rate of 

0.066 inch/hour.

On March 3, the seed was planted in 30-inch rows using a custom-made plot grain drill with disc 

openers. All seed was planted at 20-30 seeds/ft of row. The seed was planted at 0.25-inch depth. 

The trial was irrigated with a minisprinkler system (R10 Turbo Rotator, Nelson Irrigation Corp., 

Walla Walla, WA) for even stand establishment from March 4 to April 29. Risers were spaced 25 ft 

apart along the flexible polyethylene hose laterals that were spaced 30 ft apart and the water 

application rate was 0.10 inch/hour. A total of 1.72 inches of water was applied with the 

minisprinkler system. Seed emerged by late April. Starting June 24, the field was irrigated with the 

drip system. A total of 3.73 inches of water was applied with the drip system from June 24 to July 7. 

The field was not irrigated further in 2005. 

Plant stands were uneven. None of the species flowered in 2005. In early October, 2005 more seed 

was received from the Rocky Mountain Research Station for replanting. The empty lengths of row 

were replanted by hand on October 26, 2005 and fall and winter moisture was allowed to germinate 

the seed. In the spring of 2006, the plant stands of the replanted species were excellent, except for

P. deustus. On November 11, 2006, the Penstemon deustus plots were replanted again at 30 seeds/ft 

of row. 
PLANT MATERIALS AND CULTURAL PRACTICES

139

Cultural Practices in 2006

On October 27, 2006, 50 lb phosphorus (P)/acre and 2 lb zinc (Zn)/acre were injected through the 

drip tape to all plots of each species. On November 17, all plots had Prowl® at 1 lb ai/acre broadcast 

on the soil surface for weed control. Irrigations for all species were initiated on May 19 and 

terminated on June 30. 

Cultural Practices in 2007

Penstemon acuminatus and P. speciosus were sprayed with Aza-Direct® at 0.0062 lb ai/acre on May 

14 and 29 for lygus bug control. Irrigations for each species were initiated and terminated on 

different dates (Table 2). 

Cultural Practices in 2008

On November 9, 2007 and on April 15, 2008, Prowl at 1 lb ai/acre was broadcast on all plots for 

weed control. Capture® 2EC at 0.1 lb ai/acre was sprayed on all plots of Penstemon acuminatus and

P. speciosus on May 20 for lygus bug control. Irrigations for each species were initiated and 

terminated on different dates (Table 2). Due to substantial stand loss, all plots of P. deustus were 

disked out.

Cultural Practices in 2009

On March18, Prowl at 1 lb ai/acre and Volunteer® at 8 oz/acre were broadcast on all plots for weed 

control. The flowering, irrigation timing, and harvest timing were recorded for each species (Table 

2). On December 4, 2009, Prowl at 1 lb ai/acre was broadcast for weed control on all plots. 

Cultural Practices in 2010

The flowering, irrigation, and harvest timing of the established wildflowers were recorded for each 

species (Table 2). On November 17, Prowl at 1 lb ai/acre was broadcast on all plots for weed 

control. Due to substantial stand loss, all plots of P. acuminatus were disked out.

Cultural Practices in 2011

The timing of flowering, irrigations, and harvests varied by species (Table 2). On November 9, 

Prowl at 1 lb ai/acre was broadcast on all plots for weed control. 

Cultural Practices in 2013

On April 3, Select Max at 32 oz/acre was broadcast for grass weed control on all plots of Penstemon 

speciosus. 

Cultural Practices in 2014

On April 18, Orthene at 8 oz/acre was broadcast to all plots of Penstemon speciosus for lygus bug 

control. On April 29, 5 lb Fe/acre was applied through the drip tape to all plots of Penstemon 

speciosus. 

Cultural Practices in 2015

On April 20, Orthene at 8 oz/acre was broadcast to all plots of Penstemon speciosus for lygus bug 

control. 
PLANT MATERIALS AND CULTURAL PRACTICES

140

Weeds were controlled in the first year after fall planting by hand weeding. In subsequent years, 

weeds were controlled by yearly applications of Prowl (soil active herbicide) and hand weeding. 

Stands of P. speciosus have regenerated by natural reseeding. Prowl was not applied after 2011 to 

encourage natural reseeding. While natural reseeding might be advantageous for maintaining stands 

for irrigation research, natural reseeding might be disadvantageous for seed production, because of 

changes in the genetic makeup of the stand over time. 

Plant Establishment: Penstemon cyaneus, P. deustus, and P. pachyphyllus

On November 25, 2009 seed of Penstemon cyaneus, P. deustus, and P. pachyphyllus was planted in 

30-inch rows using a custom-made plot grain drill with disk openers. All seed was planted on the 

soil surface at 20-30 seeds/ft of row. After planting, sawdust was applied in a narrow band over the 

seed row at 0.26 oz/ft of row (558 lb/acre). Following planting and sawdust application, the beds 

were covered with row cover. The row cover (N-sulate, DeWitt Co., Inc., Sikeston, MO) covered 

four rows (two beds) and was applied with a mechanical plastic mulch layer. The field was irrigated 

for 24 hours on December 2, 2009 due to very dry soil conditions.

Cultural Practices in 2010

After the newly planted wildflowers had emerged, the row cover was removed in April. The 

irrigation treatments were not applied to these wildflowers in 2010. Stands of Penstemon cyaneus 

and P. pachyphyllus were not adequate for yield estimates.

Gaps in the rows were replanted by hand on November 5. The replanted seed was covered with a 

thin layer of a mixture of 50 percent sawdust and 50 percent hydro seeding mulch (Hydrostraw 

LLC, Manteno, IL) by volume. The mulch mixture was sprayed with water using a backpack 

sprayer. 

Cultural Practices in 2011

Seed from the middle 2 rows in each plot of Penstemon deustus was harvested with a small plot 

combine. Seed from the middle 2 rows in each plot of the other species was harvested manually. 

Cultural Practices in 2012

Many areas of the wildflower seed production were suffering from severe iron deficiency early in 

the spring of 2012. On April 13, 2012, 50 lb nitrogen/acre, 10 lb phosphorus/acre, and 0.3 lb iron 

(Fe)/acre was applied to all plots as liquid fertilizer injected through the drip tape. On April 23, 

2012, 0.3 lb Fe/acre was applied to all plots of as liquid fertilizer injected through the drip tape.

A substantial amount of plant death occurred in the Penstemon deustus plots during the winter and 

spring of 2011/2012. For P. deustus, only the undamaged parts in each plot were harvested. Seed of 

all species was harvested and cleaned manually. On October 26, dead P. deustus plants were 

removed and the empty row lengths were replanted by hand at 20-30 seeds/ft of row. After planting, 

sawdust was applied in a narrow band over the seed row. Following planting and sawdust 

application, the beds were covered with row cover. 

Cultural Practices in 2013

Seed of Penstemon cyaneus and P. pachyphyllus was harvested manually. The replanted P. deustus 

did not flower in 2013.Weeds were controlled by hand weeding as necessary.
PLANT MATERIALS AND CULTURAL PRACTICES

141

Cultural Practices in 2014

On April 29, 0.3 lb Fe/acre was applied through the drip tape to all plots. Seed of Penstemon 

deustus was harvested with a small plot combine. Seed of the other species was harvested manually. 

Cultural Practices in 2015

Seed of Penstemon deustus was harvested with a small plot combine. Seed of the other species was 

harvested manually. 

Stands of P. cyaneus and P. pachyphyllus are currently poor, but might regenerate from natural 

reseeding. While natural reseeding might be advantageous for maintaining stands for irrigation 

research, natural reseeding might be disadvantageous for seed production, because of changes in the 

genetic makeup of the stand over time. Weeds were controlled each year by hand weeding. 

Irrigation for Seed Production 

In April, 2006 each planted strip of Penstemon acuminatus, P. deustus, and P. speciosus was 

divided into plots 30 ft long. Each plot contained four rows of each species. The experimental 

designs were randomized complete blocks with four replicates. The three treatments were a nonirrigated check, 1 inch of water applied per irrigation, and 2 inches of water applied per irrigation. 

Each treatment received 4 irrigations that were applied approximately every 2 weeks starting with 

bud formation and flowering. The amount of water applied to each treatment was calculated by the 

length of time necessary to deliver 1 or 2 inches through the drip system. Irrigations were regulated 

with a controller and solenoid valves. After each irrigation, the amount of water applied was read on 

a water meter and recorded to ensure correct water applications. 

In March of 2007, the drip-irrigation system was modified to allow separate irrigation of the species 

due to different timings of flowering. Penstemon deustus and P. speciosus were irrigated together, 

but separately from Penstemon acuminatus. 

Irrigation dates are found in Table 2. In 2007, irrigation treatments were inadvertently continued 

after the fourth irrigation. Irrigation treatments for all species were continued until the last irrigation 

on June 24, 2007. 

Penstemon cyaneus, P. deustus (2nd planting), and P. pachyphyllus were irrigated together starting 

in 2011 using the same procedures as previously described.

Flowering, Harvesting, and Seed Cleaning 

Flowering dates for each species were recorded (Table 2). Each year, the middle two rows of each 

plot were harvested when seed of each species was mature (Table 2). The plant stand for the first 

planting of P. deustus was too poor to result in reliable seed yield estimates. Replanting of P. 

deustus in the fall of 2006 did not result in adequate plant stand in the spring of 2007.

All species were harvested with a Wintersteiger small plot combine. Penstemon deustus seed pods 

were too hard to be opened in the combine; the unthreshed seed was precleaned in a small clipper 

seed cleaner and then seed pods were broken manually by rubbing the pods on a ribbed rubber mat. 

The seed was then cleaned again in the small clipper seed cleaner. The other species were threshed 

in the combine and the seed was further cleaned using a small clipper seed cleaner. Seed of P. 
PLANT MATERIALS AND CULTURAL PRACTICES

142

cyaneus, P. pachyphyllus, and P. speciosus were harvested by hand when stands became too poor 

for combining.

Results and Discussion

Precipitation from January through June in 2009, 2012, and 2014 was close to the average of 5.8 

inches (Table 3). Precipitation from January through June in 2006, 2010, and 2011 was higher than 

the average of 5.8 inches. Precipitation from January through June in 2007, 2008, 2013, and 2015 

was lower than the average of 5.8 inches The accumulated growing degree-days (50-86°F) from 

January through June in 2006, 2007, 2013, 2014, and 2015 were higher than average (Table 3). 

Flowering and Seed Set

Penstemon acuminatus and P. speciosus had poor seed set in 2007, partly due to a heavy lygus bug 

infestation that was not adequately controlled by the applied insecticides. In the Treasure Valley, 

the first hatch of lygus bugs occurs when 250 degree-days (52°F base) are accumulated. Data 

collected by an AgriMet weather station adjacent to the field indicated that the first lygus bug hatch 

occurred on May 14, 2006; May 1, 2007; May 18, 2008; May 19, 2009; and May 29, 2010. The 

average (1995-2010) lygus bug hatch date was May 18. 

Penstemon acuminatus and P. speciosus start flowering in early May (Table 2). The earlier lygus 

bug hatch in 2007 probably resulted in harmful levels of lygus bugs present during a larger part of 

the Penstemon spp. flowering period than normal. Poor seed set for P. acuminatus and P. speciosus

in 2007 also was related to poor vegetative growth compared to 2006 and 2008. 

In 2009, all plots of P. acuminatus and P. speciosus again showed poor vegetative growth and seed

set. Root rot affected all plots of P. acuminatus in 2009, killing all plants in two of the four plots of 

the wettest treatment (2 inches per irrigation). Root rot affected the wetter plots of P. speciosus in 

2009, but the stand partially recovered due to natural reseeding.

Seed Yields

Penstemon acuminatus, Sharpleaf Penstemon

There was no significant difference in seed yield between irrigation treatments for P. acuminatus in 

2006 (Tables 4 and 5). Precipitation from March through June was 6.4 inches in 2006. The 64-yearaverage precipitation from March through June is 3.6 inches. The wet weather in 2006 could have 

attenuated the effects of the irrigation treatments. 

In 2007, seed yield showed a quadratic response to irrigation rate. Seed yields were maximized by 

4.0 inches of water applied in 2007. 

In 2008, seed yield showed a linear response to applied water. 

In 2009, there was no significant difference in seed yield between treatments. However, due to root 

rot affecting all plots in 2009, the seed yield results were compromised. 

By 2010, substantial lengths of row contained only dead plants. Measurements in each plot showed 

that plant death increased with increasing irrigation rate. The stand loss was 51.3, 63.9, and 
PLANT MATERIALS AND CULTURAL PRACTICES

143

Table 2. Penstemon flowering, irrigation, and seed harvest dates by species in 2006-2015. 

Malheur Experiment Station, Oregon State University, Ontario, OR.

Flowering dates Irrigation dates

Species Year Start Peak End Start End Harvest

Penstemon acuminatus 2006 2-May 10-May 19-May 19-May 30-Jun 7-Jul

2007 19-Apr 25-May 19-Apr 24-Jun 9-Jul

2008 29-Apr 5-Jun 29-Apr 11-Jun 11-Jul

2009 2-May 10-Jun 8-May 12-Jun 10-Jul

Penstemon cyaneus 2011 23-May 15-Jun 8-Jul 13-May 23-Jun 18-Jul

2012 16-May 30-May 10-Jun 27-Apr 7-Jun 27-Jun

2013 3-May 21-May 5-Jun 24-Apr 5-Jun 11-Jul

2014 5-May 13-May 8-Jun 29-Apr 10-Jun 14-Jul

2015 5-May 12-Jun 21-Apr 3-Jun 13-Jul

Penstemon deustusa 2006 10-May 19-May 30-May 19-May 30-Jun 4-Aug

2007 5-May 25-May 25-Jun 19-Apr 24-Jun

2008 5-May 20-Jun

2011 23-May 20-Jun 14-Jul 13-May 23-Jun 16-Aug

2012 16-May 30-May 4-Jul 27-Apr 7-Jun 7-Aug

2013 3-May 18-May 15-Jun 24-Apr 5-Jun

2014 10-May 20-May 19-Jun 29-Apr 10-Jun 21-Jul

2015 1-May 10-Jun 21-Apr 3-Jun 23-Jul

Penstemon pachyphyllus 2011 10-May 30-May 20-Jun 13-May 23-Jun 15-Jul

2012 23-Apr 2-May 10-Jun 27-Apr 7-Jun 26-Jun

2013 26-Apr 21-May 24-Apr 5-Jun 8-Jul

2014 22-Apr 5-May 4-Jun 29-Apr 10-Jun 13-Jul

2015 24-Apr 5-May 26-May 21-Apr 3-Jun 10-Jul

Penstemon speciosus 2006 10-May 19-May 30-May 19-May 30-Jun 13-Jul

2007 5-May 25-May 25-Jun 19-Apr 24-Jun 23-Jul

2008 5-May 20-Jun 29-Apr 11-Jun 17-Jul

2009 14-May 20-Jun 19-May 24-Jun 10-Jul

2010 14-May 20-Jun 12-May 22-Jun 22-Jul

2011 25-May 30-May 30-Jun 20-May 5-Jul 29-Jul

2012 2-May 20-May 25-Jun 2-May 13-Jun 13-Jul

2013 2-May 10-May 20-Jun 2-May 12-Jun 11-Jul

2014 29-Apr 13-May 9-Jun 29-Apr 10-Jun 11-Jul

2015 28-Apr 5-May 5-Jun 21-Apr 3-Jun 30-Jun

aSecond planting in the fall of 2009.
PLANT MATERIALS AND CULTURAL PRACTICES

144

88.5 percent for the 0-, 4-, and 8-inch irrigation treatments, respectively. The trial area was disked 

out in 2010.

Following the 2005 planting, seed yields were substantial in 2006 and moderate in 2008. P. 

acuminatus performed as a short-lived perennial.

Penstemon cyaneus, Blue Penstemon

In 2012, seed yields increased with increasing irrigation up to the highest tested of 8 inches (Tables 

4 and 5). 

In 2013, seed yields showed a quadratic response to irrigation with a maximum seed yield at 4 

inches of water applied. 

In 2015, seed yields were highest with the highest amount of water applied, 8 inches (Table 4). Seed 

yields did not respond to irrigation in 2011 and 2014.

Penstemon deustus, Scabland Penstemon

Seed yields did not respond to irrigation in any year except 2011 and 2015. 

In 2011, seed yields were highest with no irrigation (Tables 4 and 5). 

In 2015, seed showed a quadratic response to irrigation with a maximum seed yield at 5.4 inches of 

water applied. 

Penstemon pachyphyllus, Thickleaf Beardtongue

Seed yields did not respond to irrigation in 2011, 2012, 2014, and 2015 (Tables 4 and 5). 

In 2013, seed yields increased with increasing irrigation up to the highest tested of 8 inches. 

Penstemon speciosus, Royal Penstemon

In 2006-2009 and 2014 and 2015, seed yield of P. speciosus showed a quadratic response to 

irrigation rate (Tables 4 and 5). Seed yields were maximized by 4.3, 4.2, 5.0, 4.3, 5.2, and 5 inches 

of water applied in 2006, 2007, 2008, 2009, 2014, and 2015, respectively. In 2010, 2011, and 2012 

there was no difference in seed yield between treatments. 

Seed yield was low in 2007 due to lygus bug damage, as discussed previously. Seed yield in 2009 

was low due to stand loss from root rot. The plant stand recovered somewhat in 2010 and 2011, due 

in part to natural reseeding, especially in the non-irrigated plots. In 2013, seed yield increased with 

increasing water application, up to 8 inches, the highest amount tested. Averaged over 9 years, seed 

yield was maximized by 5.0 inches of water applied.

Conclusions

Subsurface drip irrigation systems were tested for native seed production because they have two 

potential strategic advantages: a) low water use, and b) the buried drip tape provides water to the 

plants at depth, precluding most irrigation induced stimulation of weed seed germination on the soil 

surface and keeping water away from native plant tissues that are not adapted to a wet environment. 
PLANT MATERIALS AND CULTURAL PRACTICES

145

Due to the semi-arid environment, supplemental irrigation may often be required for successful 

flowering and seed set because soil water reserves may be exhausted before seed formation. The 

total irrigation requirements for these semi-arid-land species were low and varied by species (Table 

6). Penstemon acuminatus did not respond to irrigation in these trials. In 6 years of testing, seed 

yields of P. deustus only responded to irrigation in 2015. Natural rainfall was sufficient to maximize 

seed production in the absence of weed competition.

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant No. 

2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National Institute of 

Food and Agriculture.

Table 3. Early season precipitation and growing degree-days at the Malheur Experiment 

Station, Ontario, OR, 2006-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2006 9 3.1 1273

2007 3.1 1.9 1406

2008 2.9 1.2 1087

2009 5.8 3.9 1207

2010 8.3 4.3 971

2011 8.3 3.9 856

2012 5.8 2.3 1228

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.
PLANT MATERIALS AND CULTURAL PRACTICES

Table 4. Native wildflower seed yield in response to irrigation rate (inches/season) in 2006 through 2015. Malheur Experiment Station, 

Oregon State University, Ontario, OR.

Species Year 0 inches 4 inches 8 inches LSD (0.05) Species Year 0 inches 4 inches 8 inches LSD (0.05)

lb/acre lb/acre 

Penstemon acuminatusa 2006 538.4 611.1 544 NS Penstemon pachyphyllus 2011 569.9 337.6 482.2 NS

2007 19.3 50.1 19.1 25.5b 2012 280.5 215 253.7 NS

2008 56.2 150.7 187.1 79 2013 159.4 196.8 249.7 83.6

2009 20.7 12.5 11.6 NS 2014 291.7 238.6 282.1 NS

2010 -- Stand disked out -- 2015 89.5 73.5 93.3 NS

Average 278.2 212.3 272.2 NS

Penstemon speciosusa 2006 163.5 346.2 213.6 134.3

Penstemon cyaneus 2011 857.2 821.4 909.4 NS 2007 2.5 9.3 5.3 4.7b

2012 343.3 474.6 581.2 202.6b 2008 94 367 276.5 179.6

2013 221.7 399.4 229.2 74.4 2009 6.8 16.1 9 6.0b

2014 213.9 215.4 215.1 NS 2010 147.2 74.3 69.7 NS

2015 130.5 144.7 262.9 80.8 2011 371.1 328.2 348.6 NS

Average 366.2 405.1 452.4 NS 2012 103.8 141.1 99.1 NS

2013 8.7 80.7 138.6 63.7

Penstemon deustusc 2006 1246.4 1200.8 1068.6 NS 2014 76.9 265.6 215.1 76.7

2007 120.3 187.7 148.3 NS 2015 105.4 207.3 173.7 50.3

2008 -- Stand disked out -- Average 108.3 177.8 151.1 40.2

2011 637.6 477.8 452.6 NS

2012 308.7 291.8 299.7 NS

2013 --- no flowering ---

2014 356.4 504.8 463.2 NS

2015 20.0 76.9 67.0 43.7b

Average 333.0 339.9 321.4 NS

a Planted March, 2005, areas of low stand replanted by hand in October 2005.

bLSD (0.10)

c Planted March, 2005, areas of low stand replanted by hand in October 2005 and whole area 

replanted in October 2006. Yields in 2006 are based on small areas with adequate stand. 

*Yields in 2007 are based on whole area of very poor and uneven stand. 
PLANT MATERIALS AND CULTURAL PRACTICES

147

Table 5. (Continued on next page.) Regression analysis for native wildflower seed yield (y) in 

response to irrigation (x) (inches/season) using the equation y = a + bx + cx2 in 2006- 2015, and 4 

to 10-year averages. For the quadratic equations, the amount of irrigation that resulted in 

maximum yield was calculated using the formula: -b/2c, where b is the linear parameter and c is 

the quadratic parameter. Malheur Experiment Station, Oregon State University, Ontario, OR. 

Penstemon acuminatus

Maximum 

seed yield

Water applied for 

Year Intercept linear quadratic R maximum yield 2 P

2006 538.4 35.6 -4.4 0.03 NSa

2007 19.3 15.4 -1.9 0.44 0.1 50 4

2008 56.2 30.9 -1.8 0.63 0.05 188 8.5

2009 19.5 -1.1 0.23 NS

Average 165.6 17.1 -1.8 0.1 NS

Penstemon cyaneus Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2011 836.6 6.5 0.01 NS

2012 855.8 29.7 0.84 0.001 1094 8

2013 221.7 87.9 -10.9 0.63 0.05 399 4

2014 214.2 0.1 0.01 NS

2015 113.2 16.6 0.32 NS

Average 360.6 9.2 0.24 NS

Penstemon deustus Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2006 1260.9 -22.2 0.05 NS

2007 120.3 30.2 -3.3 0.19 NS

2011 615.2 -23.1 0.35 0.05 615 0

2012 304.6 -1.1 0.01 NS

2014 356.4 60.8 -5.9 0.26 NS

2015 20.0 22.6 -2.1 0.42 0.10 81 5.4

Average 333.0 4.9 -0.79 0.03 NS

a Not significant. There was no statistically significant trend in seed yield in response to the amount of 

irrigation.
PLANT MATERIALS AND CULTURAL PRACTICES

148

Table 5. (Continued from previous page.) Regression analysis for native wildflower seed yield in 

response to irrigation rate (inches/season) in 2006 - 2014, and 4 to 10-year averages. Malheur 

Experiment Station, Oregon State University, Ontario, OR.

Penstemon pachyphyllus Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2011 507.1 -11 0.04 NS

2012 263.1 -3.3 0.01 NS

2013 156.8 11.3 0.33 0.1 247 8

2014 275.6 -1.2 0.01 NS

2015 89.5 -8.5 1.1 0.06 NS

Average 278.2 -32.2 3.9 0.21 NS

Penstemon speciosus Maximum 

seed yield

Water applied for 

Year intercept linear quadratic R maximum yield 2 P

lb/acre inches/season

2006 163.5 85.1 -9.9 0.66 0.05 346 4.3

2007 2.5 3.2 -0.4 0.48 0.1 9 4.2

2008 94.1 113.7 -11.4 0.56 0.05 378 5

2009 6.8 4.4 -0.5 0.54 0.05 16 4.2

2010 147.2 29.8 -2.1 0.35 NSa

2011 360.6 -2.8 0.01 NS

2012 103.8 19.3 -2.5 0.3 NS

2013 11 16.2 0.77 0.001 141 8

2014 76.9 77.1 -7.5 0.62 0.05 276 5.2

2015 105.4 42.4 -4.2 0.64 0.05 212 5.0

Average 108.3 29.1 -2.9 0.58 0.05 181 5.0

a Not significant. There was no statistically significant trend in seed yield in response to the amount of 

irrigation.

Table 6. Amount of irrigation water for maximum Penstemon seed yield, years to seed set, and life 

span. A summary of multi-year research findings, Malheur Experiment Station, Oregon State 

University, Ontario, OR.

Species Optimum amount of irrigation for seed production

Year of first 

seed set

Approximate

life span

inches/season

from fall 

planting years

Penstemon acuminatus 0 in wetter years, 4 in warm, dry years 1 3

Penstemon cyaneus 0 in wetter years, 4 to 8 in drier years 1 3

Penstemon deustus response to irrigation in one out of 6 years 2 3

Penstemon pachyphyllus no response in 2011, 2012, 2014, 2015, 8 inches in 2013 (drier year) 1-2 3

Penstemon speciosus 0 in cool, wet years, 4 to 8 in warm, dry years 1 3
PLANT MATERIALS AND CULTURAL PRACTICES

149

4. Prairie Clover and Basalt Milkvetch Seed Production in Response to Irrigation 

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, Lamont D. Saunders, Malheur 

Experiment Station

Oregon State University

Ontario, OR 

Doug Johnson, Shaun Bushman

USDA-ARS Forage and Range Research Lab

Logan, UT

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID 

Summary

Legumes are important components of rangeland vegetation in the Intermountain West due to 

their supply of protein to wildlife and livestock, and contribution of nitrogen to rangeland 

productivity. Seed of selected native legumes is needed for rangeland restoration, but cultural 

practices for native legume production are largely unknown. The seed yield response of three 

native legume species to irrigation was evaluated starting in 2011. Four biweekly irrigations 

applying either 0, 1, or 2 inches of water (a total of 0, 4 inches, or 8 inches/season) were tested. 

Over the five year period of study, Dalea searlsiae (Searl’s prairie clover) seed yield was 

maximized by 6 - 9 inches of water applied per season in warmer, drier years and by 0 inches of 

water applied per season in cooler, wetter years. Dalea ornata (western prairie clover) seed yield 

was maximized by 4 - 8 inches of water applied per season in warmer, drier years and by 0 

inches of water applied per season in cooler, wetter years. Astragalus filipes (basalt milkvetch) 

seed yield was not responsive to irrigation. 

Introduction

Native wildflower seed is needed to restore rangelands of the Intermountain West. Commercial 

seed production is necessary to provide the quantity of seed needed for restoration efforts. A 

major limitation to economically viable commercial production of native wildflower (forb) seed 

is stable and consistent seed productivity over years. 

In rangelands, the natural variations in spring rainfall and soil moisture result in highly 

unpredictable water stress at flowering, seed set, and seed development; which for other seed 

crops is known to compromise seed yield and quality. 

Native wildflower plants are not well adapted to croplands. Native plants are often not 

competitive with crop weeds in cultivated fields. Poor competitiveness with weeds could also 

limit wildflower seed production. Both sprinkler and furrow irrigation can provide supplemental 

water for seed production, but these irrigation systems risk further encouraging weeds. Also, 

sprinkler and furrow irrigation can lead to the loss of plant stand and seed production due to 

fungal pathogens. By burying drip tapes at 12-inch depth and avoiding wetting the soil surface, 

experiments were designed to assure flowering and seed set without undue encouragement of 
PLANT MATERIALS AND CULTURAL PRACTICES

150

weeds or opportunistic diseases. The trials reported here tested the effects of three low rates of 

irrigation on the seed yield of three native wildflower legume species (Table 1) planted in 2009. 

Table 1. Wildflower species planted in the fall of 2009 at the Malheur Experiment Station, Oregon 

State University, Ontario, OR. 

Species Common names Growth habit

Dalea searlsiae Searls’ prairie clover Perennial

Dalea ornata Western prairie clover, Blue Mountain prairie clover Perennial

Astragalus filipes Basalt milkvetch Perennial

Materials and Methods

Plant Establishment

Each of three species was planted in four rows, 30 inches apart, in a 10-foot-wide strip about 450 

feet long on Nyssa silt loam at the OSU Malheur Experiment Station, Ontario, Oregon. The soil 

had a pH of 8.3 and 1.1% organic matter. In October 2009, two drip tapes 5 feet apart (T-Tape 

TSX 515-16-340) were buried at 12-inch depth to irrigate the four rows in the plot. Each drip 

tape irrigated two rows of plants. The flow rate for the drip tape was 0.34 gal/min/100 ft at 8 psi 

with emitters spaced 16 inches apart, resulting in a water application rate of 0.066 inch/hour.

On November 25, 2009 seed of three species (Table 1) was planted in 30-inch rows using a 

custom-made plot grain drill with disk openers. All seed was planted on the soil surface at 20-30 

seeds/ft of row. After planting, sawdust was applied in a narrow band over the seed row at 0.26 

oz/ft of row (558 lb/acre). Following planting and sawdust application, the beds were covered 

with row cover. The row cover (N-sulate, DeWitt Co., Inc., Sikeston, MO) covered four rows 

(two beds) and was applied with a mechanical plastic mulch layer. The field was irrigated for 24 

hours on December 2, 2009 due to very dry soil conditions.

After the newly planted wildflowers had emerged, the row cover was removed in April, 2010. 

The variable irrigation treatments were not applied to these legumes until 2011. 

Each year, weeds were controlled by hand weeding as necessary. Seed from the middle 2 rows in 

each plot was harvested manually (Table 2).

Irrigation for Seed Production 

In April, 2011, each strip of each wildflower species was divided into twelve 30-ft plots. Each 

plot contained four rows of each species. The experimental design for each species was a 

randomized complete block with four replicates. The three treatments were a non-irrigated 

check, 1 inch of water applied per irrigation, and 2 inches of water applied per irrigation. Each 

treatment received 4 irrigations applied approximately every 2 weeks starting at bud formation 

and flowering. The amount of water applied to each treatment was calculated by the length of 

time necessary to deliver 1 or 2 inches through the drip system. Irrigations were regulated with a 

controller and solenoid valves. 

The drip-irrigation system was designed to allow separate irrigation of the species due to 

different timings of flowering and seed formation. The irrigation treatments of the two Dalea

spp. were applied together. The Astragalus filipes was irrigated separately. Flowering, irrigation, 

and harvest dates were recorded (Table 2). 
PLANT MATERIALS AND CULTURAL PRACTICES

151

Seed Beetle Control

Harvested seed pods of Dalea ornata, D. searlsiae, and Astragalus filipes had extensive damage 

from feeding by seed beetles in 2013 and 2014; indicating that control measures during and 

following flowering would be necessary to maintain seed yields. On May 21, 2015, Capture 2EC 

at 6.4 oz/acre (0.1 lb ai/acre) and Rimon at 12 oz/acre (0.08 lb ai/acre) were broadcast in the 

evening to minimize harm to pollinators. On May 28, Rimon at 12 oz/acre was broadcast in the 

evening to minimize harm to pollinators. 

Table 2. Native wildflower flowering, irrigation, and seed harvest dates by species. 

Malheur Experiment Station, Oregon State University, Ontario, OR. 

Flowering Irrigation

Species Year Start Peak End Start End Harvest

Dalea searlsiae

2011 8-Jun 20-Jun 20-Jul 27-May 6-Jul 21-Jul

2012 23-May 10-Jun 30-Jun 11-May 21-Jun 10-Jul

2013 13-May 15-Jun 8-May 19-Jun 29-Jun

2014 15-May 4-Jun 24-Jun 6-May 17-Jun 1-Jul

2015 13-May 26-May 16-Jun 5-May 17-Jun 22-Jun

Dalea ornata

2011 8-Jun 20-Jun 20-Jul 27-May 6-Jul 22-Jul

2012 23-May 10-Jun 30-Jun 11-May 21-Jun 11-Jul

2013 13-May 21-May 15-Jun 8-May 19-Jun 28-Jun

2014 15-May 4-Jun 24-Jun 6-May 17-Jun 1-Jul

2015 5-May 26-May 22-Jun 5-May 17-Jun 25-Jun

Astragalus filipes

2011 20-May 26-May 30-Jun 13-May 23-Jun 18-Jul

2012 28-Apr 23-May 19-Jun 11-May 21-Jun 5-Jul

2013 3-May 10-May 25-May 8-May 19-Jun 28-Jun

2014 5-May 13-May 28-May 29-Apr 10-Jun 24-Jun

2015 17-Apr 13-May 1-Jun 21-Apr 3-Jun 16-Jun

Results and Discussion

Precipitation from January through June was close to average in 2012, 2014, and 2015, higher 

than average in 2011, and lower than average in 2013 (Table 3). The accumulation of growing 

degree days (50 to 86o F) was increasingly higher than average from 2012 to 2015, and was 

below average in 2011 (Table 3). Flowering and seed harvest were early in 2015, probably due to 

warmer weather and greater accumulation of degree days.

Dalea searlsiae, Searl’s Prairie Clover

In 2012, 2014, and 2015 seed yields showed a quadratic response to irrigation (Tables 4 and 5). 

Maximum seed yields were achieved with 6.6, 8.9, and 6.6 inches of water applied in 2012, 
PLANT MATERIALS AND CULTURAL PRACTICES

152

2014, and 2015, respectively. In 2013, seed yields increased with increasing irrigation rate up to 

the highest tested of 8 inches. In 2011, seed yields were highest with no irrigation. Averaged 

over the 5 years, seed yield showed a quadratic response to irrigation with a maximum seed yield 

at 6.8 inches of water applied.

Dalea ornata, Western Prairie Clover

Seed yields showed a quadratic response to irrigation in 2012, 2013, 2014, and 2015 with a 

maximum seed yield at 7.7, 8.1, 6.9, and 4.3 inches of water applied, respectively (Tables 4 and 

5). Seed yields did not respond to irrigation in 2011. Averaged over the 5 years, seed yield 

showed a quadratic response to irrigation with a maximum seed yield at 5.4 inches of water 

applied.

Astragalus filipes, Basalt Milkvetch 

Seed yields only responded to irrigation in 2013, when 4 inches of applied water was among the 

irrigation rates resulting in the highest yield (Tables 4 and 5). Low seed yields of basalt 

milkvetch are related to low plant stand and high seed pod shatter that makes seed recovery 

problematic.

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant 

No. 2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National 

Institute of Food and Agriculture.

Table 3. Early season precipitation and growing degree-days at the Malheur Experiment 

Station, Ontario, OR, 2006-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2006 9 3.1 1273

2007 3.1 1.9 1406

2008 2.9 1.2 1087

2009 5.8 3.9 1207

2010 8.3 4.3 971

2011 8.3 3.9 856

2012 5.8 2.3 1228

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.
PLANT MATERIALS AND CULTURAL PRACTICES

153

Table 4. Native wildflower seed yield in response to irrigation rate 

(inches/season). Malheur Experiment Station, Oregon State University, 

Ontario, OR.

Species Year 0 inches 4 inches 8 inches LSD (0.05)

--------------- lb/acre ----------------

Dalea searlsiae

2011 262.7 231.2 196.3 50.1

2012 175.5 288.8 303.0 93.6

2013 14.8 31.7 44.4 6.1

2014 60.0 181.4 232.2 72.9

2015 221.2 330.7 344.2 68.3

Average 146.9 212.7 224.0 36.8

Dalea ornata

2011 451.9 410.8 351.7 NSa

2012 145.1 365.1 431.4 189.3

2013 28.6 104.6 130.4 38.8

2014 119.4 422.9 476.3 144.1

2015 212.9 396.7 267.2 117.0b

Average 185.6 344.1 317.2 57.9

Astragalus filipes

2011 87 98.4 74 NS

2012 22.7 12.6 16.1 NS

2013 8.5 9.8 6.1 2.7b

2014 56.6 79.3 71.9 NS

2015 17.8 12.5 11.6 NS

Average 38.5 35.2 36.0 NS

a NS = not significant, b LSD (0.10)
PLANT MATERIALS AND CULTURAL PRACTICES

154

Table 5. Regression analysis for native wildflower seed yield (y) in response to irrigation (x) 

(inches/season) using the equation y = a + bx + cx2. For the quadratic equations, the amount of 

irrigation that resulted in maximum yield was calculated using the formula: -b/2c, where b is the linear 

parameter and c is the quadratic parameter. Malheur Experiment Station, Oregon State University, 

Ontario, OR.

Dalea searlsiae

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2011 263.3 -8.3 0.49 0.05 263 0

2012 175.5 40.7 -3.1 0.62 0.05 309 6.6

2013 15.5 3.7 0.54 0.01 45 8

2014 60.0 39.1 -2.2 0.79 0.001 234 8.9

2015 221.2 39.4 -3.0 0.56 0.05 350 6.6

Average 146.9 23.3 -1.7 0.64 0.01 226 6.8

Dalea ornata

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

2011 454.9 -12.5 0.11 NSa

2012 145.1 74.2 -4.8 0.65 0.01 432 7.7

2013 28.6 25.3 -1.6 0.88 0.001 130 8.1

2014 119.4 107.1 -7.8 0.87 0.001 487 6.9

2015 212.9 85.1 -9.8 0.69 0.05 398 4.3

Average 185.6 62.8 -5.8 0.83 0.01 356 5.4

Astragalus filipes

Year intercept linear quadratic R Maximum seed yield Water applied for maximum yield 2 P

lb/acre inches/season

2011 90.6 -1.6 0.01 NS

2012 19.7 -0.8 0.04 NS

2013 8.5 0.9 -0.2 0.25 NS

2014 56.6 9.4 -0.9 0.08 NS

2015 17.1 -0.8 0.16 NS

Average 43.3 -0.2 0.01 NS

aNot significant. There was no statistically significant trend in seed yield in response to the amount of irrigation. 
PLANT MATERIALS AND CULTURAL PRACTICES

155

5. Native Beeplant (Cleome spp.) Seed Production in Response to Irrigation in a SemiArid Environment

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR, 2015 

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID

Summary

Beeplant (Cleome spp.) are annual species that favor pollinators in the Intermountain West. 

Beeplant seed is desired for rangeland restoration activities, but little cultural practice 

information is known for their seed production. The seed yield response of Cleome serrulata

(Rocky Mountain beeplant) and Cleome lutea (yellow spiderflower or yellow beeplant) to four 

biweekly irrigations applying either 0, 1 inch of water, or 2 inches of water (total of 0, 4 inches, 

or 8 inches/season) was evaluated over multiple years. Cleome serrulata seed yield was 

maximized by 8 inches of water applied per season in 2011, but did not respond to irrigation in 

2012, 2014, or 2015. Cleome lutea seed yield did not respond to irrigation in 2012, 2014, or 

2015. Cleome stands were lost to flea beetles in 2013.

Introduction

Native wildflower seed is needed to restore rangelands of the Intermountain West. Commercial 

seed production is necessary to provide the quantity of seed needed for restoration efforts. A 

major limitation to economically viable commercial production of native wildflower (forb) seed 

is stable and consistent seed productivity over years. 

In natural rangelands, the annual variation in spring rainfall and soil moisture result in highly 

unpredictable water stress at flowering, seed set, and seed development; which for other seed 

crops is known to compromise seed yield and quality. 

Native wildflower plants are not well adapted to croplands. Native plants are often not 

competitive with crop weeds in cultivated fields. Poor competitiveness with weeds could also 

limit wildflower seed production. Both sprinkler and furrow irrigation could provide 

supplemental water for seed production, but these irrigation systems risk further encouraging 

weeds. Also, sprinkler and furrow irrigation can lead to the loss of plant stand and seed 

production due to fungal pathogens. 

By burying drip tapes at 12-inch depth and avoiding wetting the soil surface, experiments were 

designed to assure flowering and seed set without undue encouragement of weeds or 

opportunistic diseases. The trials reported here tested the effects of three low rates of irrigation 

on the seed yield of Cleome serrulata (Rocky Mountain beeplant) and Cleome lutea (Yellow 

beeplant). 
PLANT MATERIALS AND CULTURAL PRACTICES

156

Materials and Methods

Plant Establishment

Each species was planted in separate strips containing four rows, 30 inches apart (a 10-foot-wide 

strip), and about 450 feet long on Nyssa silt loam at the OSU Malheur Experiment Station, 

Ontario, Oregon. The soil had a pH of 8.3 and 1.1% organic matter. In October 2010, two drip 

tapes five feet apart (T-Tape TSX 515-16-340) were buried at 12-inch depth to irrigate the four 

rows in the plot. Each drip tape irrigated two rows of plants. The flow rate for the drip tape was 

0.34 gal/min/100 ft at 8 psi with emitters spaced 16 inches apart, resulting in a water application 

rate of 0.066 inch/hour.

Starting in 2010, seed of Cleome serrulata was planted each year in 30-inch rows using a 

custom-made plot grain drill with disk openers in mid-November each year. All seed was planted 

on the soil surface at 20-30 seeds/ft of row in the same location each year. After planting, 

sawdust was applied in a narrow band over the seed row at 0.26 oz/ft of row (558 lb/acre). 

Following planting and sawdust application, the beds were covered with row cover. The row 

cover (N-sulate, DeWitt Co., Inc., Sikeston, MO) covered four rows (two beds) and was applied 

with a mechanical plastic mulch layer. Starting in 2011 seed of C. lutea was also planted each 

year. After the newly planted wildflowers had emerged, the row cover was removed in April 

each year. 

Starting in 2013, each spring after the row cover was removed, bird netting was placed over the 

Cleome serrulata and Cleome lutea plots to protect seedlings from bird feeding. The bird netting 

was placed over No. 9 galvanized wire hoops. 

Flea Beetle Control

Flea beetles were observed feeding on leaves of Cleome serrulata and C. lutea in April of 2012. 

On April 29, 2012, all plots of C. serrulata and C. lutea were sprayed with Capture® at 5 oz/acre 

to control flea beetles. On June 11, 2012, C. serrulata was again sprayed with Capture at 5 

oz/acre to control a re-infestation of flea beetles.

Flea beetle feeding occurred earlier in 2013 than in 2012. Upon removal of the row cover in 

March of 2013, the flea beetle damage for both species at seedling emergence was extensive 

resulting in full stand loss. Flea beetles were not observed on either Cleome species in 2014. 

On March 20, 2015, after removal of the row cover, all plots of C. serrulata and C. lutea were 

sprayed with Capture® at 5 oz/acre to control flea beetles. On April 3, 2015, all plots of C. 

serrulata and C. lutea were sprayed with Entrust at 2 oz/acre (0.03 lb ai/acre) to control flea 

beetles. 

Weeds were controlled by hand weeding as necessary.

Irrigation for Seed Production 

In April, 2011, each strip of each wildflower species was divided into twelve 30-ft plots. Each 

plot contained four rows of each species. The experimental design for each species was a 

randomized complete block with four replicates. The three treatments were a non-irrigated 

check, 1 inch of water applied per irrigation, and 2 inches of water applied per irrigation. Each 
PLANT MATERIALS AND CULTURAL PRACTICES

157

treatment received 4 irrigations that were applied approximately every 2 weeks starting with bud 

formation and flowering. The amount of water applied to each treatment was calculated by the 

length of time necessary to deliver 1 or 2 inches through the drip system. Irrigations were 

regulated with a controller and solenoid valves. After each irrigation, the amount of water 

applied was read on a water meter and recorded to ensure correct water applications. 

Table 1. Cleome serrulata and Cleome lutea flowering, irrigation, and seed harvest dates by 

species. Malheur Experiment Station, Oregon State University, Ontario, OR. 

Flowering dates Irrigation dates

Species Year Start Peak End Start End Harvest

Cleome serrulata 2011 25-Jun 30-Jul 15-Aug 21-Jun 2-Aug 26-Sep

2012 12-Jun 30-Jun 30-Jul 13-Jun 25-Jul 24-Jul to 30-Aug

2013 Full stand loss

2014 4-Jun 24-Jun 22-Jul 20-May 1-Jul 11-Jul to 30-Jul

2015 20-May 24-Jun 15-Sep 20-May 30-Jun 1-Jul to 15-Aug

Cleome lutea 2012 16-May 15-Jun 30-Jul 2-May 13-Jun 12-Jul to 30-Aug

2013 Full stand loss, fleabeetle damage

2014 29-Apr 4-Jun 22-Jul 23-Apr 3-Jun 23-Jun to 30-Jul

2015 8-Apr 13-May 6-Jul 17-Apr 27-May 4-Jun to 30-Jul

Table 2. Early season precipitation and growing degree-days at the Malheur 

Experiment Station, Ontario, OR, 2006-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2011 8.3 3.9 856

2012 5.8 2.3 1228

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.

The drip-irrigation system was designed to allow separate irrigation of each species due to 

different timings of flowering and seed formation. Flowering, irrigation, and harvest dates were 

recorded (Table 2). In 2014, after the 4 bi-weekly irrigations ended, Cleome serrulata and 

Cleome lutea received three additional bi-weekly irrigations starting on August 12 in an attempt 

to extend the flowering and seed production period. On August 12, 50 lb N/acre, 30 lb P/acre, 

and 0.2 lb Fe/acre were applied through the drip tape to all plots of Cleome serrulata and Cleome 

lutea.
PLANT MATERIALS AND CULTURAL PRACTICES

158

Flowering and Harvest

The two species have a long flowering and seed set period (Table 2), making mechanical 

harvesting difficult. Mature seed pods were harvested manually 2 to 4 times each year.

Table 3. Cleome serrulata and Cleome lutea seed yield in response to 

irrigation rate (inches/season). Malheur Experiment Station, Oregon State 

University, Ontario, OR.

Irrigation rate

0 inches 4 inches 8 inches

LSD 

Species Year (0.05)

------------- lb/acre --------------

Cleome serrulata 2011 446.5 499.3 593.6 100.9b

2012 184.3 162.9 194.7 NSa

2013 No stand, fleabeetle damage

2014 66.3 80 91.3 NS

2015 54.0 41.0 37.9 NS

Average 150.8 157.1 183.7 NS

Cleome lutea 2012 111.7 83.7 111.4 NS

2013 No stand, fleabeetle damage

2014 207.1 221.7 181.7 NS

2015 136.9 80.5 113.0 NS

Average 151.9 128.6 135.4 NS

a Not significant. There was no statistically significant trend in seed yield in 

response to the amount of irrigation.

b LSD (0.10)

Results and Discussion

Precipitation from January through June in 2012, and 2014 was close to the average of 5.8 inches 

(Table 2). Precipitation from January through June in 2013 and 2015 was lower than the average 

of 5.8 inches. Precipitation from January through June in 2011 was higher than the average of 

5.8 inches. The accumulated growing degree-days (50-86° F) from January through June in 

2013, 2014, and 2015 were higher than average (Table 2) and was associated with early 

flowering and seed harvest. 

Cleome serrulata, Rocky Mountain Beeplant

In 2011, seed yields increased with increasing irrigation up to the highest tested of 8 inches 

(Tables 3 and 4). Seed yields did not respond to irrigation in 2012, 2014, or 2015. There was no 

plant stand in 2013 due to early, severe flea beetle damage. The additional irrigations applied 

starting on August 12 in 2014 did result in an extension/resumption of flowering, but seed 

harvested in mid-October was not mature.

The winter and spring of 2011 were wetter and this annual plant developed well, responded to 

later irrigation, and had higher seed yield. The pattern of results over years suggests that Cleome 
PLANT MATERIALS AND CULTURAL PRACTICES

159

spp. may need early irrigation in drier years in addition to irrigation during flowering and seed 

set.

Cleome lutea, Yellow Spiderflower or Yellow Beeplant

Seed yields did not respond to irrigation in 2012, 2014, or 2015 (Tables 3 and 4). There was no 

plant stand in 2013. Early attention to flea beetle control is essential for Cleome lutea seed 

production. The additional irrigations applied starting on August 12 in 2014 did not result in an 

extension or resumption of flowering.

Table 4. Regression analysis for Cleome serrulata and Cleome lutea seed yield (y) in response 

to irrigation (x) (inches/season) using the equation y = a + bx + cx2. Malheur Experiment 

Station, Oregon State University, Ontario, OR. 

Cleome serrulata Maximum 

seed yield

Water applied 

for maximum 

Year intercept linear quadratic R yield 2 P

lb/acre inches/season

2011 439.6 18.4 0.35 0.05 587 8

2012 175.4 1.3 0.01 NSa

2014 66.7 3.1 0.16 NS

2015 52.4 -2.0 0.08 NS

Average 206 6.5 0.33 NS

Cleome lutea

Maximum 

seed yield

Water applied 

for maximum 

Year intercept linear quadratic R yield 2 P

lb/acre inches/season

2012 102.4 -0.031 0.01 NS

2014 207.1 10.4 -1.7 0.2 NS

2015 122.0 -3.0 0.08 NS

Average 159.3 -1.6 0.04 NS

References

Cane, J. H. 2008. Breeding biologies, seed production and species-rich bee guilds of 

Cleome lutea and C. serrulata (Cleomaceae). Plant Species Biology 23: 152-158.

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, 

Oregon State University, Malheur County Education Service District, and supported by 

Formula Grant No. 2015-31100-06041 and Formula Grant No. 2015-31200-06041 from 

the USDA National Institute of Food and Agriculture.
PLANT MATERIALS AND CULTURAL PRACTICES

160

6. Irrigation Requirements for Seed Production of Various Native Wildflower Species 

Started in the Fall of 2012

Clinton C. Shock, Erik B. G. Feibert, Alicia Rivera, Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR, 2015 

Nancy Shaw, Francis Kilkenny

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID

Introduction

Commercial seed production of native wildflowers is necessary to provide the quantity of seed 

needed for restoration of Intermountain West rangelands. Native wildflower plants may not be 

well adapted to croplands. Native plants are often not competitive with crop weeds in cultivated 

fields. This poor competitiveness with weeds could limit wildflower seed production. Both 

sprinkler and furrow irrigation could provide supplemental water for seed production, but these 

irrigation systems risk further encouraging weeds. Also, sprinkler and furrow irrigation can lead 

to the loss of plant stand and seed production due to fungal pathogens. By burying drip tapes at 

12-inch depth and avoiding wetting the soil surface, experiments were designed to assure 

flowering and seed set without undue encouragement of weeds or opportunistic diseases. The 

trials reported here tested the effects of three low rates of irrigation on the seed yield of 13 native 

wildflower species (Table 1). 

Table 1. Wildflower species planted in the fall of 2012 at the Malheur Experiment 

Station, Oregon State University, Ontario, OR. 

Species Common name Longevity Row spacing (inches)

Chaenactis douglasii Douglas' dustymaiden perennial 30

Crepis intermediab Limestone hawksbeard perennial 30

Cymopterus bipinnatusa Hayden's cymopterus perennial 30

Enceliopsis nudicaulis nakedstem sunray perennial 30

Heliomeris multiflora showy goldeneye perennial 30

Ipomopsis aggregata scarlet gilia biennial 15

Ligusticum canbyi Canby's licorice-root perennial 30

Ligusticum porteri Porter's licorice-root perennial 30

Machaeranthera canescens hoary tansyaster perennial 30

Nicotiana attenuata coyote tobacco perennial 30

Phacelia linearis threadleaf phacelia annual 15

Phacelia hastata silverleaf phacelia perennial 15

Thelypodium milleflorum manyflower thelypody biennial 30

a

recently classified as Cymopterus nivalis S. Watson “snowline springparsley”. Planted in the fall 

of 2009.

b Planted in the fall of 2011.
PLANT MATERIALS AND CULTURAL PRACTICES

161

Materials and Methods

Plant Establishment

Each wildflower species was planted on 60-inch beds in rows 450 feet long on Nyssa silt loam at 

the OSU Malheur Experiment Station, Ontario, Oregon. The soil had a pH of 8.3 and 1.1% 

organic matter. In October 2012, drip tapes (T-Tape TSX 515-16-340) were buried at 12-inch 

depth in the center of each bed to irrigate the rows in the plot. The flow rate for the drip tape was 

0.34 gal/min/100 ft at 8 psi with emitters spaced 16 inches apart, resulting in a water application 

rate of 0.066 inch/hour.

On October 30, 2012 seed of 11 species (Table 1) was planted in either 15-inch or 30-inch rows 

using a custom-made plot grain drill with disk openers. All seed was planted on the soil surface 

at 20-30 seeds/ft of row. After planting, sawdust was applied in a narrow band over the seed row 

at 0.26 oz/ft of row (558 lb/acre). Following planting and sawdust application, the beds were 

covered with row cover. The row cover (N-sulate, DeWitt Co., Inc., Sikeston, MO) covered four 

rows (two beds) and was applied with a mechanical plastic mulch layer. Cymopterus bipinnatus 

was planted on November 25, 2009, and Crepis intermedia was planted on November 28, 2011 

as previously described. 

Weeds were controlled by hand weeding as necessary.

Cultural Practices for Cymopterus bipinnatus and Crepis intermedia

Starting in March following fall planting, the row cover was removed. Immediately following 

the removal of the row cover, bird netting was placed over the seedlings to prevent bird feeding 

on young seedlings and new shoots. The bird netting was placed over No. 9 galvanized wire 

hoops. During seedling emergence, wild bird seed was placed several hundred feet from the trial 

to attract quail away from the trials. Bird netting was removed in early May. Bird netting was 

applied and removed each spring. On April 13, 2012, 50 lb nitrogen/acre, 10 lb phosphorus/acre, 

and 0.3 lb iron (Fe)/acre was applied to all plots of Cymopterus bipinnatus as liquid fertilizer 

injected through the drip tape. 

Cultural Practices in 2013

Starting on March 29, 2013, the row cover was removed and bird netting applied for the species 

planted in the fall of 2012. Bird netting was removed in early May. On July 26, all plots of 

Machaeranthera canescens were sprayed with Capture at 19 oz/acre (0.3 lb ai/acre) for aphid 

control. On October 31, seed of Phacelia linearis was planted as previously described. 

Due to poor stand, seed of Chaenactis douglasii was replanted on November 1, as previously 

described. Stand of Nicotiana attenuata was extremely poor and seed was unavailable for 

replanting. 

Cultural Practices in 2014

Starting in late March, 2014, the row cover was removed and bird netting applied. Bird netting 

was removed in early May. Stand of Chaenactis douglasii, which was replanted in the fall of 

2013, was poor and did not allow evaluation of irrigation responses.
PLANT MATERIALS AND CULTURAL PRACTICES

162

On November 11, Phacelia linearis, Nicotiana attenuata, and Thelypodium milleflorum were 

replanted as previously described.

Cultural Practices in 2015

Starting in late March 2015, the row cover was removed and bird netting applied. Bird netting 

was removed in early May. 

Irrigation for Seed Production 

In March of 2010 for Cymopterus bipinnatus, and March of 2013 for the other species, the strip 

of each wildflower species was divided into twelve 30-ft long plots. Each plot contained four 

rows of each species. The experimental design for each species was a randomized complete 

block with four replicates. The three treatments were a non-irrigated check, 1 inch of water per 

irrigation, and 2 inches of water per irrigation. Each treatment received four irrigations that were 

applied approximately every 2 weeks starting at bud formation and flowering. The amount of 

water applied to each treatment was calculated by the length of time necessary to deliver 1 or 2 

inches through the drip system. Irrigations were regulated with a controller and solenoid valves. 

The drip-irrigation system was designed to allow separate irrigation of each species due to 

different timings of flowering and seed formation. All species were irrigated separately except 

the two Phacelia spp. and the two Ligusticum spp. Flowering, irrigation, and harvest dates were 

recorded (Table 2) with the exception of Nicotiana attenuata which did not germinate in 2014 

and the Ligusticum spp. which did not flower. 

All species were harvested manually, except Phacelia hastata. Phacelia hastata was harvested 

with a small plot combine. Chaenactis douglasii and Crepis intermedia were harvested once a 

week with a leaf blower in vacuum mode. Machaeranthera canescens seed was harvested by 

cutting and windrowing the plants. After drying for 2 days the Machaeranthera canescens plants 

were beaten on plastic tubs to separate the seed heads from the stalks. Seed of all species was 

cleaned manually. 

Results and Discussion

Precipitation from January through July in 2013 (2.6 inches) was below and in 2014 (5.1 inches) 

and 2015 (5.3) was close to the 72-year average of 6.0 inches (Table 3). The accumulation of 

growing degree days (50 to 86o F) was higher than average in 2013, 2014, and 2015 (Table 3).

Stands of Ligusticum porteri and Ligusticum canbyi were poor and uneven not permitting 

evaluation of irrigation responses. 

Stands of Chaenactis douglasii were poor in 2013 and 2014, not permitting evaluation of 

irrigation responses. After replanting in the fall of 2013 and 2014, adequate stand was 

established allowing evaluations of irrigation responses in 2015. 

Stand of Nicotiana attenuata was uneven and did not permit evaluation of irrigation responses in 

2015. 
PLANT MATERIALS AND CULTURAL PRACTICES

163

Ipomopsis aggregata had very little flowering in 2013, then flowered and set seed in 2014. The 

existing stand of Ipomopsis aggregata died over the winter of 2014/2015 indicating a biennial 

growth habit. 

Cymopterus bipinnatus did not flower in either 2010 or 2011, and had very little flowering in 

2012. 

Stand of replanted Phacelia linearis was very poor, but was replaced by an excellent volunteer 

stand of Phacelia hastata originating from unharvested seed of the adjacent Phacelia hastata 

stand. Irrigation responses for Phacelia hastata were evaluated for the new stand and for the 3 

year-old stand. 

Crepis intermedia flowered and produced seed for the first time in 2015, the third year since fall 

planting in 2011. 

Extensive die-off of Enceliopsis nudicaulis occurred over the winter of 2014/2015. The die-off 

was more severe in the plots receiving the highest amount of irrigation. 

Seed Yield Responses (Tables 4 and 5)

Chaenactis douglasii (Douglas' dustymaiden) seed yields of did not respond to irrigation in 

2015. 

Crepis intermedia (limestone hawksbeard) seed yields increased with increasing irrigation rate 

up to the highest tested of 8 inches in 2015.

Cymopterus bipinnatus (Hayden's cymopterus) seed yields did not respond to irrigation in 2013. 

In 2014, seed yields increased with increasing irrigation rate up to the highest tested of 8 inches. 

In 2015, seed yields showed a quadratic response to irrigation with a maximum seed yield at 4.2 

inches of water applied. 

Enceliopsis nudicaulis (nakedstem sunray) seed yield was very low and was not responsive to 

irrigation in 2013. In 2014, seed yield showed a quadratic response to irrigation with a maximum 

seed yield at 5.4 inches of water applied. Significant stand loss occurred over the winter of 

2014/2015, especially in the irrigated plots. Seed yields of E. nudicaulis were substantially 

reduced in 2015 and were highest without irrigation. Seed yields have been very low each year 

due at least in part to very low plant stands.

Heliomeris multiflora (showy goldeneye)seed yield increased with increasing irrigation rate up 

to the highest tested of 8 inches in 2013, 2014, and 2015.

Ipomopsis aggregata (scarlet gilia) seed yields were highest with 4 inches of applied water in 

2014.
PLANT MATERIALS AND CULTURAL PRACTICES

164

Machaeranthera canescens (hoary tansyaster) seed yields showed a quadratic response to 

irrigation with a maximum seed yield at 2.4 inches of water applied in 2013. In 2014, 2015, and 

averaged over the 3 years, seed yields of M. canescens were not responsive to irrigation. 

Phacelia hastata (silverleaf phacelia) (planted in the fall of 2012) seed yields, showed a 

quadratic response to irrigation with a maximum seed yield at 5.4 and 7.5 inches of water applied 

in 2013 and 2014, respectively. In 2015, seed yield of P. hastata was not responsive to irrigation, 

possibly due to loss of stand in this weak perennial. 

Seed yields of Phacelia hastata, planted in the fall of 2014, increased with increasing irrigation 

rate up to the highest tested of 8 inches.

Seed yields of Phacelia linearis (threadleaf phacelia) showed a quadratic response to irrigation 

in 2013 with a maximum seed yield at 6.2 inches of water applied. In 2014, seed yields of P. 

linearis were not responsive to irrigation.

The establishment of Thelypodium milleflorum (manyflower thelypody) has been difficult and 

plant stands have been poor. Seed yield of T. milleflorum did not respond to irrigation in 2014. 

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant 

No. 2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National 

Institute of Food and Agriculture.
PLANT MATERIALS AND CULTURAL PRACTICES

165

Table 2. Native wildflower flowering, irrigation, and seed harvest dates by species. Malheur 

Experiment Station, Oregon State University, Ontario, OR.

Flowering dates Irrigation dates

Year Start Peak End Start End Harvest

Chaenactis douglasii, Douglas' dustymaiden

2013 23-May 30-Jun 15-Jul 22-May 3-Jul 2-Jul, 22-Jul

2014 20-May 15-Jul 13-May 24-Jun poor stand

2015 5-May 10-Jul 5-May 17-Jun 6-8 to 7-15

Machaeranthera canescens, hoary tansyaster

2013 13-Aug 1-Oct 17-Jul 28-Aug 2-Oct

2014 20-Aug 17-Sep 5-Oct 22-Jul 2-Sep 6-Oct

2015 10-Aug 17-Sep 1-Oct 11-Aug 22-Sep 6-Oct, 15-Oct

Phacelia hastata, silverleaf phacelia

2013 17-May 30-Jul 22-May 3-Jul 30-Jul (0 in), 7-Aug, 19-Aug (8 in)

2014 5-May 10-Jul 29-Apr 10-Jun 14-Jul

2015 (1st year) 28-Apr 26-May 7-Aug 20-May 30-Jun 6-Aug

2015 (3rd year) 28-Apr 26-May 7-Aug 29-Apr 10-Jun 7-Jul (0 in), 21-Jul (4, 8 in)

Phacelia linearis, threadleaf phacelia

2013 3-May 16-May 15-Jun 2-May 12-Jun 2-Jul

2014 5-May 4-Jun 1-Jul 1-May 10-Jun 7-Jul

2015 winter die-off

Enceliopsis nudicaulis, nakedstem sunray

2013 30-Jun 15-Sep 3-Jul 14-Aug 8-Aug to 30-Aug

2014 5-May 1-Jul 30-Jul 6-May 17-Jun 14-Jul to 30-Aug

2015 28-Apr 13-May 5-Aug 29-Apr 10-Jun 2-Jun to 15-Aug

Heliomeris multiflora, showy goldeneye

2013

2014 15-Jul 30-Aug 5-Jun 17-Jun 8-Aug, 15-Aug, 28-Aug

2015 20-May 20-Jun 30-Aug 13-May 24-Jun 15-Jul to 15-Aug

Cymopterus bipinnatus, Hayden's cymopterus

2013 5-Apr 15-May 12-Apr 22-May 10-Jun

2014 7-Apr 29-Apr 7-Apr 20-May 16-jun

2015 25-May 24-Apr 1-Apr 13-May 8-Jun

Ipomopsis aggregate, scarlet gilia

2013 31-Jul very little flowering 31-Jul 11-Sep

2014 22-Apr 13-May 30-Jul 23-Apr 3-Jun 20-Jun

2015 winter die-off

Thelypodium milleflorum, manyflower thelypody

2013 no flowering

2014 22-Apr 5-May 10-Jun 23-Apr 3-Jun 2-Jul

2015 no flowering

Crepis intermedia, Limestone hawksbeard

2015 28-Apr 5-May 1-Jun 21-Apr 3-Jun 6-1 to 7-2
PLANT MATERIALS AND CULTURAL PRACTICES

166

Table 3. Early season precipitation and growing degree-days at the Malheur 

Experiment Station, Ontario, OR, 2013-2015.

Precipitation (inches) Growing degree-days (50-86°F)

Year Jan-June April-June Jan-June

2013 2.6 1.4 1319

2014 5.1 1.6 1333

2015 4.8 2.7 1575

72-year average 5.8 2.7 1178a

a22-year average.

Table 4. Native wildflower seed yield in response to season long irrigation rate (inches). 

Malheur Experiment Station, Oregon State University, Ontario, OR.

Irrigation rate

Species Year 0 inches 4 inches 8 inches

LSD 

(0.05)

--------------- lb/acre ----------------

Chaenactis douglasii 2015 132.1 137.6 183.3 NSa

Crepis intermedia 2015 75.5 75.8 153.7 58.1

Cymopterus bipinnatus 2013 194.2 274.5 350.6 NS

2014 1236.2 1934 2768.5 844.7

2015 312.3 749.0 374.9 240.7

Average 580.9 1078.8 968.7 325b

Enceliopsis nudicaulis 2013 2.3 6.8 5.9 NS

2014 1.5 34.6 29.1 20.7

2015 15.7 3.2 4.4 7.3

Average 6.5 16.6 13.1 NS

Heliomeris multiflora 2013 28.7 57.6 96.9 NS

2014 154.6 200.9 271.7 107.3b

2015 81.7 115.6 188.2 58.2

Average 88.3 124.7 185.6 46.8

Ipomopsis aggregata 2014 47.1 60.9 63.6 9

Machaeranthera canescens 2013 206.1 215 124.3 73.6

2014 946.1 1210.2 1026.3 NS

2015 304.1 402.6 459.1 NS

Average 163.0 240.3 233.3 NS

Phacelia hastata 2013 35.3 102.7 91.2 35.7

(planted fall 2012) 2014 87.7 305.7 366.4 130.3

2015 78.8 79.3 65.0 NS

Average 67.3 162.6 174.2 34.5

Phacelia hastata

(planted fall 2014) 2015 0.0 21.4 50.4 13.7

Phacelia linearis 2013 121.4 306.2 314.2 96

2014 131.9 172.9 127.2 NS

Average 126.7 239.5 220.7 87.2

Thelypodium milleflorum 2014 200.5 246.2 205.6 NS
PLANT MATERIALS AND CULTURAL PRACTICES

167

Table 5. Regression analysis for native wildflower seed yield (y) in response to irrigation (x) 

(inches/season) using the equation y = a + bx + cx2. For the quadratic equations, the amount of irrigation 

that resulted in maximum yield was calculated using the formula: -b/2c, where b is the linear parameter 

and c is the quadratic parameter. Malheur Experiment Station, Oregon State University, Ontario, OR.

Species Year intercept linear quadratic R

2 P

Maximum 

seed yield

Water applied for 

maximum yield

lb/acre inches/season

Chaenactis douglasii 2015 125.4 6.4 0.08 NS

Crepis intermedia 2015 58.6 12.7 0.32 0.1 160 8

Cymopterus bipinnatus 2013 194.9 19.6 0.07 NS

2014 1214.6 190.6 0.41 0.05 2740 8

2015 312.3 210.5 -25.3 0.46 0.10 750 4.2

Average 580.9 200.5 -19.0 0.24 NS

Enceliopsis nudicaulis 2013 3.1 0.4 0.16 NS

2014 1.5 13.1 -1.2 0.6 0.05 37 5.4

2015 13.4 -1.4 0.29 0.1 13 0.0

Average 6.5 4.2 -0.4 0.27 NS

Heliomeris multiflora 2013 27 8.5 0.38 0.05 95 8

2014 150.5 14.6 0.27 0.1 268 8

2015 75.2 13.3 0.48 0.05 182 8

Average 84.2 12.2 0.55 0.01 181 9

Ipomopsis aggregata 2014 48.5 2.1 0.23 NS

Machaeranthera canescens 2013 206.1 14.7 -3.1 0.54 0.05 223 2.4

2014 946.1 122 -14 0.13 NS

2015 311.1 19.4 0.02 NS

Average 163.0 29.9 -2.6 0.03 NS

Phacelia hastata 2013 35.3 26.7 -2.5 0.66 0.01 108 5.4

(planted fall 2012) 2014 87.7 74.2 -4.9 0.76 0.01 367 7.5

2015 78.8 2.0 -0.5 0.04 NS

Average 67.3 34.3 -2.6 0.9 0.001 180 6.6

(planted fall 2014) 2015 -1.3 6.3 0.88 0.001 49 8

Phacelia linearis 2013 121.4 68.3 -5.5 0.69 0.01 333 6.2

2014 131.9 21.1 -2.7 0.11 NS

Average 126.7 44.7 -4.1 0.48 0.1 248 5.4

aNot significant. There was no statistically significant trend in seed yield in response to amount of irrigation.
PLANT MATERIALS AND CULTURAL PRACTICES

168

7. Direct Surface Seeding Systems for the Establishment of Native Plants in 2015

Clinton Shock, Erik Feibert, Alicia Rivera, Lamont Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR

Francis Kilkenny, Nancy Shaw

U.S. Forest Service

Rocky Mountain Research Station

Boise, ID 

Introduction

Seed of native plants is needed to restore rangelands of the Intermountain West. Reliable 

commercial seed production is needed to make seed readily available. Direct seeding of native 

range plants has been generally problematic, especially for certain species. Fall planting is 

important for many species because their seed requires a period of cold to break dormancy 

(vernalization). Fall planting of native seed has resulted in poor stands in some years at the 

Malheur Experiment Station. Loss of soil moisture, soil crusting, and bird damage are some 

detrimental factors hindering emergence of fall planted seed. Previous trials at the Malheur 

Experiment Station have examined seed pelleting, planting depth, and soil anti-crustants with a 

group of species that have problematic establishment (Shock et al. 2010). Planting at depth with 

soil anti-crustant improved emergence compared to surface planting. Seed pelleting did not 

improve emergence. Despite these positive results, emergence was extremely poor for all species 

tested due in part to soil crusting and bird damage.

In established native perennial fields at the Malheur Experiment Station, and in rangelands, we 

have observed prolific natural emergence from seed that falls on the soil surface and is covered 

by thin layers of organic debris. In 2011, 2012, and 2013, trials tested the effect of seven planting 

systems on surface planted seed (Table 1; Shock et al. 2012, 2013, 2014). Row cover can be a 

protective barrier against soil desiccation and bird damage. Sawdust might mimic the protective 

effect of organic debris, while sand can help hold the seed in place. Seed treatment can protect 

the emerging seed from fungal pathogens that might cause seed decomposition or seedling 

damping off. The treatments did not test all possible combinations of factors, but tested 

combinations that might be likely to result in adequate stand establishment based on previous 

observations. In 2015, the seven planting systems were tested for emergence of 11 important 

species, most of which are problematic to establish. Seven of these species are native to Malheur 

County and surrounding rangelands and forests. 

Materials and Methods

Ten species for which stand establishment has been problematic were chosen. An eighth species 

(Penstemon speciosus) was chosen as a check, because it has reliably produced good stands at 

the Malheur Experiment Station in Ontario, OR. Seed weights for all species were determined. A 

portion of the seed was treated with a liquid mix of the fungicides Thiram® and Captan (10g 

Thiram, 10g Captan in 0.5 liter of water). Seed weights of the treated seeds were determined 

after treatment. The seed weights of untreated and treated seed were used to make seed packets 
PLANT MATERIALS AND CULTURAL PRACTICES

169

containing approximately 300 seeds each. The seed packets were then assigned to one of six 

treatments (Table 1). The planned planting time of November was postponed to January due to 

unusually high precipitation and cold weather in November and December. The trial was planted 

manually on January 7, 8, and 9, 2015. The experimental design was a randomized complete 

block with six replicates. Plots were one 30-inch-wide by 5-ft-long bed. Two seed rows were 

planted within each bed. 

After planting, the sawdust was applied in a narrow band over the seed row at 0.26 oz/ft of row 

(558 lb/acre). For the treatments receiving both sawdust and sand, the sand was applied at 0.65 

oz/ft of row (1,404 lb/acre) as a narrow band over the sawdust. Following planting and sawdust 

and sand applications, some beds were covered with row cover. The row cover (N-sulate, DeWitt 

Co., Inc., Sikeston, MO) covered four rows (two beds). Since the soil was frozen, preventing the 

use of the mechanical plastic mulch applicator, the row cover was applied manually. Clamps 

were used to fasten the row cover. The hydroseed mulch treatment was not applied due to the 

low air temperature. On April 15, 2015, the row cover was removed and emergence counts were 

made in every plot. 

Tetrazolium tests were conducted to determine seed viability of each species (Table 2). The 

tetrazolium results were used to correct the emergence data to emergence of viable seed. Data 

were analyzed using analysis of variance (General Linear Models Procedure, NCSS, Kaysville, 

UT). Means separation was determined using a protected Fisher’s least significant difference test 

at the 5 percent probability level, LSD (0.05). 

Results and Discussion

Overall, emergence in the trial in 2015 was poor. The late planting and dry spring probably 

contributed to the poor emergence. Emergence and stand of Phacelia hastata, Ligusticum 

porteri, Ligusticum canbyi, Nicotiana attenuata, Thelypodium milleflorum, and Ipomopsis 

aggregata was 10% or less (Table 3). There was no significant difference in stand between 

planting systems for Phacelia hastata, Ligusticum porteri, Ligusticum canbyi, Thelypodium 

milleflorum, and Ipomopsis aggregata.

There were statistically significant differences in stand between planting systems for five 

species. The row cover with sawdust plus seed treatment resulted in higher stands than no row 

cover (bare ground) with sawdust and seed treatment for Machaeranthera canescens, Phacelia 

linearis, and Heliomeris multiflora (Table 3). Sawdust added to the row cover plus seed 

treatment only improved stands of Phacelia linearis. 

Adding seed treatment to sawdust plus row cover improved stands of Phacelia linearis and 

reduced stands of Chaenactis douglasii and Heliomeris multiflora. Adding sand to sawdust, seed 

treatment, plus row cover increased stand for Penstemon speciosus. 

In 2013 (Shock et al. 2014), the same establishment systems were tested with 15 species, 

including all of the species in the 2015 trial. In 2013, systems including row cover improved 

stand of 6 of the species including Chaenactis douglasii, Machaeranthera canescens, 

Thelypodium milleflorum, and Penstemon speciosus. The combined planting system that 

included seed treatment improved the stand of Penstemon speciosus and reduced the stand of 
PLANT MATERIALS AND CULTURAL PRACTICES

170

Phacelia hastata and Ipomopsis aggregata. The treatment combination that included seed 

covering with sand improved stand of Chaenactis douglasii and Heliomeris multiflora. 

In 2014, the same establishment systems were tested with 8 of the species in the 2015 trial 

(Shock et al. 2015). Overall, emergence in 2014 was poor. December of 2013 and January of 

2014 precipitation was about 50% lower than normal and could have contributed to the poor 

emergence. There was no significant difference in stand between treatments for Phacelia 

linearis, Phacelia hastata, Heliomeris multiflora, or Ligusticum canbyi.

In 2014, systems including row cover improved stand of Machaeranthera canescens and

Ligusticum porteri. Sawdust added to the row cover plus seed treatment only improved stands of 

Ligusticum porteri. Adding seed treatment to sawdust plus row cover did not improve stands of 

any species. Adding sand to sawdust, seed treatment, plus row cover increased the stand of 

Penstemon speciosus. 

Planting systems including row cover have been the most consistent factor for improving stand 

establishment over the years of trials at the Malheur Experiment Station (Shock et al. 2011, 

2012, 2013, 2014). Seed treatment, sawdust, and sand are factors that, for some species, in some 

years, have shown value in improving stand but their performance has not been consistent.

References

Shock, C. C.; Feibert, E. B. G.; Saunders, L. D.; Shaw, N. 2010. Emergence of native plant seeds 

in response to seed pelleting, planting depth, scarification, and soil anti-crusting treatment. 

Annual Report. 2009. Corvallis, OR: Oregon State University, Malheur Experiment Station: 218-

222.

Shock, C. C.; Feibert, E. B. G.; Saunders, L. D.; Shaw, N. 2012. Direct surface seeding strategies 

for establishment of Intermountain West native plants for seed production. Annual Report. 2011. 

Corvallis, OR: Oregon State University, Malheur Experiment Station: 130-135. 

Shock, C. C.; Feibert, E. B. G.; Saunders, L. D.; Johnson, D.; Bushman, S. 2013. Direct surface 

seeding strategies for establishment of two native legumes of the Intermountain West. Annual 

Report. 2012. Corvallis, OR: Oregon State University, Malheur Experiment Station: 132-137. 

Shock, C. C.; Feibert, E. B. G.; Saunders, L. D.; Shaw, N. 2014. Direct surface seeding systems 

for successful establishment of native wildflowers. Annual Report. 2013. Corvallis, OR: Oregon 

State University, Malheur Experiment Station: 159-165.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Kilkenny, F.; Shaw, N. 2015. Direct 

surface seeding strategies for emergence of native plants in 2014. Annual Report. 2014. 

Corvallis, OR: Oregon State University, Malheur Experiment Station: 275-279.
PLANT MATERIALS AND CULTURAL PRACTICES

171

Table 1. Planting systems evaluated for emergence of 

eight native plant species. Mouse bait packs were 

scattered over the trial area. Malheur Experiment Station, 

Oregon State University, Ontario, OR, 2015.

No.

Row 

cover

Seed 

treatmenta Sawdust Sand Mulchb

1 yes yes yes no no

2 yes yes no no no

3 yes no yes no no

4 no yes yes no no

5 yes yes yes yes no

6 no yes no no yes

7 no no no no no

aMixture of Captan and Thiram fungicides for prevention of seed 

decomposition and seedling damping off.

bHydroseed mulch was not tested in 2015 due to January 

planting, and unlike previous years, only the seed treatment for 

system No. 6.

Table 2. Seed weights and tetrazolium test (seed viability) results for seed used for the planting systems 

treatments in the fall of 2014 and evaluated in the spring of 2015. Malheur Experiment Station, Oregon 

State University, Ontario, OR.

Species Common name

Pre-plant untreated 

seed weight

Tetrazolium 

test

seeds/g %

Chaenactis douglasii Douglas' dustymaiden 600 69

Machaeranthera canescens hoary tansyaster 1,020 78

Phacelia hastata silverleaf phacelia 996 96

Phacelia linearis threadleaf phacelia 3,213 98

Heliomeris multiflora showy goldeneye 1,600 94

Ligusticum porteri Porter's licorice-root 206 28

Ligusticum canbyi Canby's licorice-root 256 17

Nicotiana attenuata showy penstemon 7,823 81

Thelypodium milleflorum manyflower thelypody 5,482 93

Ipomopsis aggregata scarlet gilia 693 40

Penstemon speciosus showy penstemon 608 86
PLANT MATERIALS AND CULTURAL PRACTICES

Table 3. Plant stands of eleven native plant species on April 15, 2015 in response to seven planting systems used in January of 2015. Emergence for each 

species was corrected to the percent emergence of viable seed. Oregon State University, Malheur Experiment Station, Ontario, OR.

Species

Row cover, 

Seed treatment, 

Sawdust

Row cover, 

Seed treatment

Row cover, 

Sawdust

Seed treatment, 

Sawdust

Row cover, 

Seed treatment,

Sawdust, 

Sand Seed treatment Untreated check LSD (0.05)

---------------------------------- % establishment -------------------------------------

Chaenactis douglasii 3.9 2.9 14.8 2.6 4.3 1.1 7.3 3.9

Machaeranthera canescens 35.4 30.7 30.5 17.7 27.4 8.3 17.4 12.8

Phacelia hastata 0.9 2.5 1.8 2.2 2.4 2.3 1.3 NS

Phacelia linearis 9.0 4.0 3.1 5.0 11.6 4.4 1.8 3.0

Heliomeris multiflora 27.5 27.1 44.4 9.1 31.6 6.0 9.9 7.1

Ligusticum porteri 3.4 1.8 2.4 3.6 3.6 0.2 0.6 NS

Ligusticum canbyi 0.3 0.7 1.6 5.6 7.5 0.3 0.7 NS

Nicotiana attenuata 1.2 0.8 1.8 0.2 1.3 0.0 0.3 1.1

Thelypodium milleflorum 1.4 2.1 2.1 1.2 2.2 1.6 1.6 NS

Ipomopsis aggregata 0.3 1.7 2.5 0.7 2.2 0.6 0.3 NS

Penstemon speciosus 4.7 1.6 2.1 1.3 10.2 0.6 1.6 4.6
PLANT MATERIALS AND CULTURAL PRACTICES

173

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon 

State University, Malheur County Education Service District, and supported by Formula Grant No. 

2015-31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National Institute of 

Food and Agriculture.

Publications

Annual Reports

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. 2015. Native 

beeplant seed production in response to irrigation in a semi-arid environment. In: Shock, C. C., ed. 

Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual 

Report. 2014. Corvallis, OR: Oregon State University, Malheur Experiment Station; Department of 

Crop and Soil Science Ext/CrS 152: 211-216.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F.; Sampangi, 

R. S. 2015. Irrigation requirements for seed production of five native Penstemon species in a semiarid environment. p 217-230 In Shock C.C. (Ed.) In: Shock, C. C., ed. Oregon State University 

Agricultural Experiment Station, Malheur Experiment Station Annual Report. 2014. Corvallis, OR: 

Oregon State University, Malheur Experiment Station; Department of Crop and Soil Science 

Ext/CrS 152: 217-230.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F.; Sampangi. 

R. S. 2015. Irrigation requirements for seed production of five Lomatium species in a semi-arid 

environment. In: Shock, C. C., ed. Oregon State University Agricultural Experiment Station, 

Malheur Experiment Station Annual Report. 2014. Corvallis, OR: Oregon State University, 

Malheur Experiment Station; Department of Crop and Soil Science Ext/CrS 152: 231-246.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F.; Sampangi, 

R. S. 2015. Globemallow seed production is unresponsive to irrigation in a semi-arid environment. 

In: Shock, C. C., ed. Oregon State University Agricultural Experiment Station, Malheur Experiment 

Station Annual Report. 2014. Corvallis, OR: Oregon State University, Malheur Experiment Station; 

Department of Crop and Soil Science Ext/CrS 152: 247-251.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F.; Sampangi, 

R. S. 2015. Irrigation requirements for native buckwheat seed production in a semi-arid 

environment. In: Shock, C. C., ed. Oregon State University Agricultural Experiment Station, 

Malheur Experiment Station Annual Report. 2014. Corvallis, OR: Oregon State University, 

Malheur Experiment Station; Department of Crop and Soil Science Ext/CrS 152: 252-260.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Johnson, D.; Bushman, S.; Shaw, N.; 

Kilkenny, F. F. 2015. Great Basin native legume seed production in response to irrigation. In: 

Shock, C. C., ed. Oregon State University Agricultural Experiment Station, Malheur Experiment 

Station Annual Report. 2014. Corvallis, OR: Oregon State University, Malheur Experiment Station; 

Department of Crop and Soil Science Ext/CrS 152: 261-267.
PLANT MATERIALS AND CULTURAL PRACTICES

174

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F. 2015. 

Irrigation requirements for seed production of native wildflower species started in the fall of 2012. 

In: Shock, C. C., ed. Oregon State University Agricultural Experiment Station, Malheur Experiment 

Station Annual Report. 2014. Corvallis, OR: Oregon State University, Malheur Experiment Station; 

Department of Crop and Soil Science Ext/CrS 152: 268-274.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Kilkenny, F. F.; Shaw, N. 2015. Direct 

surface seeding strategies for emergence of native plants in 2014. In: Shock, C. C., ed. Oregon State 

University Agricultural Experiment Station, Malheur Experiment Station Annual Report. 2014. 

Corvallis, OR: Oregon State University, Malheur Experiment Station; Department of Crop and Soil 

Science Ext/CrS 152: 275-279.

Presentations

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Kilkenny, F. F.; Shaw, N. 2015. Update 

on stand establishment and water requirements for wildflower seed production. Great Basin 

Consortium Conference; 18 February; Boise, ID.

Shock, C. C.; Feibert, E. B. G.; Rivera, A.; Saunders, L. D.; Shaw, N.; Kilkenny, F. F. 2015. 

Irrigation requirements for seed production of five native Lomatium species. Annual Meeting of the 

American Society of Horticultural Science; 5 August; New Orleans, LA.

Shock, C. C.; Feibert, E. B. G.; Reitz, S. R.; Felix, J.; Buhrig, W. H.; Riveira, A.; Kreeft, H.; Parris, 

C.; Shaw, N.; Kilkenny, F. F.; Klauzer, J. 2015. Oregon report to W3128, scaling microirrigation 

technologies to address the global water challenge. Meeting of the Microirrigation Working Group; 

12 December; Long Beach, CA.

Field days

Feibert, E. B. G.; Shock, C. C. 2015. Establishing native wildflower seed production plantings. 

Native Wildflower Seed Production Field Day; 14 May; Oregon State University Malheur 

Experiment Station; Ontario, OR.

Shock, C. C.; Feibert, E. B. G. 2015. Irrigation of native plants for seed production. Wildflower 

Seed Production Field Day; 14 May; Oregon State University Malheur Experiment Station; Ontario, 

OR.

Shock, C. C. 2015. Opportunities with little irrigation water. Wildflower Seed Production Field 

Day; 14 May; Oregon State University Malheur Experiment Station; Ontario, OR.
PLANT MATERIALS AND CULTURAL PRACTICES

Management Applications and/or Seed Production Guidelines

Irrigation water requirements for native wildflower seed production

Clint Shock and Erik Feibert, 15 January 2016

Wildflower species irrigated with drip systems at the Malheur Experiment Station, Oregon State University, Ontario, OR.

Species Common names Flowering dates*

Irrigation 

water needs Years to first harvest Stand life Seed yield

inches/year years lb/ac per harvest

Eriogonum umbellatum Sulphur-flower buckwheat L. May to July 0-8 1 10+ 100-350

Eriogonum heracleoides Parsnip-flowered buckwheat May to June 0-4 2 5+ 50-400

Penstemon acuminatus Sharpleaf penstemon L. April to E. June <4 2 3 100-600

Penstemon deustus Scabland penstemon May to E. July 0-4 1 2 200-600

Penstemon speciosus Royal penstemon May to June 0-4 2 3 25-350

Penstemon cyaneus Blue penstemon May to June 0-8 1 3 200-800

Penstemon pachyphyllus Thickleaf beardtongue L. April to E. June <4 2 3 200-500

Lomatium dissectum Fernleaf biscuitroot April to E. May 5-8 4 8+ 300-1200

Lomatium triternatum Nineleaf biscuitroot April to E. June 4-8 2 9+ 700-2000

Lomatium grayi Gray’s biscuitroot L. March to E. May 0-5 2 9+ 300-1200

Lomatium nudicaule Bare-stem desert parsley April to May 0-8 3 4+ 500-600

Cymopterus bipinnatus Hayden's cymopterus April to May 3 4+ 300-2500

Sphaeralcea parvifolia Smallflower globemallow May to June <4 1 4-5 100-500

Sphaeralcea grossulariifolia Gooseberryleaf globemallow May to June <4 1 4-5 150-400

Sphaeralcea coccinea Scarlet globemallow May to June <4 1 4-5 100-300

Dalea searlsiae Searls’ prairie clover May to June 0-8 2 5+ 150-300

Dalea ornata Western prairie clover May to June 0-8 2 5+ 150-450

Astragalus filipes Basalt milkvetch L. April to June <4 2 4+ 10-100

Cleome serrulata Rocky mountain beeplant June to August 0-8 1 1 100-500

Cleome lutea Yellow beeplant May to July <4 1 1 100-200

Machaeranthera canescens hoary tansyaster Mid-Aug to L. Sept. 4 1 2+ 200-400

Phacelia hastata silverleaf phacelia May to July 0-8 1 2+ 100-300

Phacelia linearis threadleaf phacelia E. May to L. June 4 1 1 150-300

Enceliopsis nudicaulis nakedstem sunray May to August 4 1 2 10-35

Heliomeris multiflora showy goldeneye L. May to August 8 1 3+ 50-250

Ipomopsis aggregata scarlet gilia L. April to July 4 2 2 50-60

Thelypodium milleflorum manyflower thelypody L. April-mid June 8 2 2 200-250

*Varies with the year and location. E = Early, L = Late
PLANT MATERIALS AND CULTURAL PRACTICES

176

Management Applications

The preceding report describes irrigation and plant establishment practices that can be immediately 

implemented by seed growers. Multi-year summaries of species seed yield performance in response 

to irrigation are in the table above.

Additional Products

 Seed produced from these plantings was used to establish commercial seed production fields.

 A field tour for growers and the public was conducted 15 May 2014.

 A tour of the seed production trials was incorporated into the annual Malheur

Experiment Station Field Day activities 9 July 2014.

 Continued improvement of native plant database on the internet at: 

http://www.malag.aes.oregonstate.edu/wildflowers/

 Many of our forb production reports are available on line at www.cropinfo.net

Acknowledgements

This project was funded by the U.S. Forest Service, U.S. Bureau of Land Management, Oregon State 

University, Malheur County Education Service District, and supported by Formula Grant No. 2015-

31100-06041 and Formula Grant No. 2015-31200-06041 from the USDA National Institute of Food 

and Agriculture.
PLANT MATERIALS AND CULTURAL PRACTICES

177

Project Title Characterizing Germplasm Relationships and Maximizing 

Seedling Establishment of Utah Trefoil (Lotus utahensis

Ottley)

Project Agreement No. 15-IA-11221632-200

Principal Investigators and Contact Information

B. Shaun Bushman, Research Geneticist 

USDA-ARS Forage and Range Research Lab

Utah State University

Logan, UT 84322-6300

435.797.2901

shaun.bushman@ars.usda.gov 

Douglas A. Johnson, Plant Physiologist 

USDA-ARS Forage and Range Research Lab

Utah State University

Logan, UT 84322-6300

435.797.2901

shaun.bushman@ars.usda.gov 

Other Collaborators

Thomas Jones (USDA-ARS FRRL) and Jennifer MacAdam (Utah State Univ.)

Project Description 

Introduction

Rangeland ecosystems in the western U.S. are increasingly vulnerable to wildfires, weed invasion, 

mismanagement, and soil erosion (Pierson et al. 2011), and may not recover for decades (or longer) 

without human intervention. Many western rangelands also suffer from long-term reductions in 

biodiversity, altered nutrient and water cycling, diminished livestock and wildlife forage production, 

and increased wildfire frequency (Sheley et al. 2008). Concerns related to biodiversity as well as 

food and habitat resources for sage-grouse (Centrocercus urophasianus) and native pollinators are 

particularly important for sagebrush-steppe rangelands like the Great Basin (Rowland et al. 2008; 

Cane 2011; Cane et al. 2013). However, few North American forb species (including legumes) are 

available for use in restoration projects in the Great Basin. Leguminous forbs are of particular 

interest because they biologically fix nitrogen as well as provide high quality food for wildlife and 

native pollinators. Our research group has focused on providing germplasm sources of native 

legumes for rangeland use in the semi-arid western USA, including research on best practices for 

seed production and rangeland planting. We have developed a process that begins with collections, 

carries through evaluations and seed production practices, and ends with planting guidelines for 

rangeland restoration/revegetation (Bhattarai et al. 2008, 2010, 2011; Bushman et al. 2010; Johnson 

et al. 2008, 2011, 2012, 2013). 
PLANT MATERIALS AND CULTURAL PRACTICES

178

Utah trefoil (Lotus utahensis Ottley) naturally occurs in the southern Great Basin and the Mojave 

Basin and Range, a dry region with particular needs for restoration/revegetation. We made 19 seed 

collections across the range of distribution for Utah trefoil in southern Nevada, southern Utah, and 

northern Arizona. Common gardens of these collections were established in 2013 at three locations 

in northern Utah. These replicated plantings are under evaluation for plant development, phenology, 

morphology, seed production, and other physiological characteristics. These initial studies comprise 

important early stages in our germplasm release process and will provide a scientific basis for 

ensuring that locally adapted plant materials are characterized and released for use. To these initial 

studies, it is critical to add research that defines gene-flow and evolutionary patterns of Utah trefoil 

populations, develops seed germination and emergence protocols for commercial seed production, 

and identifies best planting practices for rangeland sites. 

Methods

We are characterizing the type of differences among collections of Utah trefoil and nearly related 

taxa in common garden plots in northern Utah, measuring biomass, heading date, seed production, 

morphological measures, and forage quality/tannin contents. We are also using AFLP DNA-based 

markers to assess collection relationships and gene flow. We will use multivariate analyses of 

collection-site environmental data, molecular marker data, and common-garden measures to create 

appropriate germplasm release strategies. 

Hard seededness is a common feature in legume species, which limits initial, uniform germination 

and subsequent establishment. Based on germplasm selected in the first portion of this research 

project, the effects of various seed treatments (scarifications, boiling water treatment, and control) 

and age of seed (newly harvested or one-year-old seed) will be investigated for Utah trefoil. All 

combinations of these treatments will be tested in a greenhouse to determine which combination of 

treatments yields the best germination and seedling establishment. 

Given the data obtained from first and second portions of this research project, the best treatment 

combination will be used in field plantings. Seeds from the most promising collections will be 

planted in replicated fall dormant and spring plantings at several locations. First and second year 

establishment/survival will be recorded at each of the test sites to identify best seeding practices. 

Anticipated Results and Discussion

From the characterization of gene-flow and population relationships, we will be able to identify 

populations of Utah trefoil and understand how the different seed transfer zones and populations 

relate to each other. From the greenhouse and field experiments, we will be able to identify the best 

seed treatments and seeding depths for Utah trefoil. The field experiments will allow us to determine 

if fall-dormant or spring plantings are the best for establishing Utah trefoil. This information will be 

published in peer-reviewed journal articles. We will work closely with seed growers and agency 

personnel to coordinate project activities, and actively participate in technology transfer 

opportunities. The ultimate outcome of this project will be the establishment of diverse forb species 

in sagebrush-steppe communities to enhance the food and habitat resources for sage-grouse and 

native pollinators in the face of global climate change. 

Management Applications

This project will provide land managers with to diversify their rangeland revegetation projects. 
PLANT MATERIALS AND CULTURAL PRACTICES

179

References

Bhattarai, K.; Bushman, B. S.; Johnson, D. A.; Carman, J. G. 2010. Phenotypic and genetic 

characterization of western prairie clover collections from the western United States. Rangeland 

Ecology and Management 63: 696-706.

Bhattarai, K.; Bushman, B. S.; Johnson, D. A.; Carman, J. G. 2011. Searls prairie clover (Dalea 

searlsiae) for rangeland revegetation: phenotypic and genetic evaluations. Crop Science 51: 716-

727.

Bhattarai, K.; Johnson, D. A.; Jones, T. A.; Connors, K. J.; Gardner, D. R. 2008. Physiological and 

morphological characterization of basalt milkvetch (Astragalus filipes): basis for plant improvement. 

Rangeland Ecology and Management 61: 444-455.

Bushman, B. S.; Bhattarai, K.; Johnson, D. A. 2010. Population structure of Astragalus filipes

collections from western North America. Botany 88: 565-574. 

Cane, J. H. 2011. Meeting wild bees’ needs on western US rangelands. Rangelands 33: 27-32.

Cane, J. H.; Johnson, C. D.; Napoles, J. R.; Johnson, D. A.; Hammon, R. 2013. Seed-feeding beetles 

(Bruchinae, Curculionidae, Brentidae) from legumes (Dalea ornata, Astragalus filipes) and other 

forbs needed for restoring rangelands of the Intermountain West. Western North American 

Naturalist 73: 477-484.

Johnson, D. A.; Bushman, B. S.; Bhattarai, K.; Connors, K. J. 2011. Notice of release of Majestic 

germplasm and Spectrum germplasm western prairie clover. Native Plants Journal 12: 249-256.

Johnson, D. A.; Bushman, B. S.; Jones, T. A.; Bhattarai, K. 2012. Identifying geographically based 

metapopulations for development of plant materials indigenous to rangeland ecosystems of the 

western USA. Progress in Botany 74: 265-291. 

Johnson, D. A.; Bushman, B. S.; Jones, T. A.; Bhattarai, K. 2013. Using common gardens and AFLP 

analyses to identify metapopulations of indigenous plant materials for rangeland revegetation in 

western USA. In: Michalk, D. L.; Millar, G. D.; Badgery, W. B.; Broadfoot, K. M. eds. Revitalizing 

grasslands to sustain our communities. Orange, Australia: New South Wales Department of Primary 

Industry: 371-372.

Johnson, D. A.; Jones, T. A.; Connors, K. J.; Bhattarai, K.; Bushman, B. S.; Jensen, K. B. 2008. 

Notice of release of NBR-1 germplasm basalt milkvetch. Native Plants Journal 9: 127-132.

Pierson, F. B.; Williams, C. J.; Hardegree, S. P.; Weltz, M. A.; Stone, J. J.; Clark, P. E. 2011. Fire, 

plant invasions, and erosion events on western rangelands. Rangeland Ecology and Management 64: 

439-449.

Rowland, M. M.; Wisdom, M. J.; Suring, L. H.; Meinke, C.W. 2006. Greater sage-grouse as an

umbrella species for sagebrush-associated vertebrates. Biological Conservation 129: 323-335.
PLANT MATERIALS AND CULTURAL PRACTICES

180

Sheley, R.; Mangold, J.; Goodwin, K.; Marks, J. 2008. Revegetation guidelines for the Great Basin: 

considering invasive weeds. ARS-168. Washington, D.C.: U.S. Department of Agriculture, 

Agricultural Research Service: 1-52. 
181

 

SEED INCREASE 
SEED INCREASE

182

Project Title Coordination of Great Basin Native Plant Project Plant 

Materials Development, Seed Increase, and Use

Project Agreement No. 12-JV-11221632-044

Principal Investigators and Contact Information 

Berta Youtie, Owner

Eastern Oregon Stewardship Services

P. O. Box 606 

Prineville, OR 97754

541.447.8166 

byoutie@crestviewcable.com 

Project Description

Introduction

In 2014, Eastern Oregon Stewardship Services (EOSS) concentrated on assisting with a bluebunch 

wheatgrass (Pseudoroegneria spicata) common garden reciprocal transplant study. This study will 

test the hypotheses that local plant material is best adapted for restoration purposes and whether seed 

zones perform well in delineating regions of local adaptation. 

Reciprocal transplant studies, where plants from multiple populations are planted in a set of sites that 

represent local and non-local climates, are useful for evaluating the effectiveness of seed transfer 

guidelines and seed zones. Seed zones and guidelines ensure that adapted plant material is 

reintroduced after fires, and may be important for long-term resilience of native grass populations. 

Objectives

 Prepare and plant bluebunch wheatgrass (Pseudoroegneria spicata) common garden study 

sites in recently burned areas in identified seed zones for reciprocal transplant studies. 

 Expand the Great Basin Native Plant Project (GBNPP) Native Seed Growers Information 

Network. 

 Increase native seed collections for GBNPP in Eastern Oregon and Northern Nevada 

according to research needs and gaps identified by provisional seed zone maps. 

Methods

Seed collections were made in 2013, plugs were grown in greenhouses and bluebunch plugs were 

planted at test sites in fall 2014 (Figure 1). In the Northern Great Basin/Snake River Plain, eight or 

more source treatments were planted within eight test sites with locations based on developed seed 

zones. Another eight sites were planted in the Columbia Plateau/Blue Mt. regions. 

Many of the test sites had sagebrush removed and were then tilled as part of seed bed preparation. 

Bluebunch wheatgrass plugs were planted into numerically identified study blocks consisting of 

several seed zones in all 16 sites, September through December, 2014 (Figures 2, 3, 4, 5 and 6). Two 

bluebunch cultivars, Anatone and Goldar, were also planted at select study locations. Two rows of 
SEED INCREASE

183

boundary plants were planted as protective borders for the bluebunch plugs at each site. After 

planting, plugs were watered (Figure 7) and plant identification numbers were recorded for future 

data collection (Figure 8). 

Results

EOSS assisted with planting six of the study sites (Table 1). 

Figure 1. Quinn #1 site in Santa Rosa Mountains in Northern Nevada seed zone 6a. 

Table 1. EOSS Assistance – Planting Sites.

SITES DATES ACTIVITIES

Central Ferry WA September 22-23 Travel and Planting

Stevens Ridge WA September 24-25 Planting and Travel

Quinn #1 NV September 29- October 1 Travel and Planting

Quinn #2 NV October 2-3 Planting and Travel

Steens Mt. OR October 15-17 Travel and Planting

Crooked River Grasslands, OR October 18 Delivering Plants
SEED INCREASE

184

 

Figure 2. Laying out plots in the Santa Rosa’s. Figure 3. Francis Kilkenny sorting bluebunch plugs for 

planting. 

 

 Figure 4. Chris and Jameson digging holes for Figure 5. Berta planting bluebunch wheatgrass plugs.

 planting grass plugs. 

 

Figure 6. Crew planting plugs in the Steens Mountains. Figure 7. Watering plugs after planting. 
SEED INCREASE

185

Figure 8. Brad St. Clair recording plug identification data after planting at Central Ferry, 

WA. 

Management Applications and/or Seed Production Guidelines

Previous work on bluebunch (St. Clair et al. 2013) will allow for selecting populations that are more 

or less adapted to specific climatic variables, as well as allow testing the effectiveness of the 

prospective seed zones. 

References

St. Clair, J. B.; Kilkenny, F. F.; Johnson, R. C.; Shaw, N. L.; Weaver, G. 2013. Genetic variation in 

adaptive traits and seed transfer zones for Pseudoroegneria spicata (bluebunch wheatgrass) in 

northwestern Unites States. Evolutionary Applications 6(6): 933-948.
SEED INCREASE

186

Project Title Seed Increase of Great Basin Native Forbs and Grasses for 

Restoration Research Projects

Project No. 14-JV-11221632-135

Principal Investigators and Contact Information

Clinton C. Shock, Director/Professor

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174, Fax 541.889.7831

clinton.shock@oregonstate.edu

Erik B. Feibert, Senior Faculty Research Assistant

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174 

erik.feibert@oregonstate.edu

Joel Felix, Assoc. Professor

Oregon State University

Malheur Experiment Station

595 Onion Avenue

Ontario, OR 97914

541.889.2174, Fax 541.889.7831

joel.felix@oregonstate.edu

Nancy Shaw, Research Botanist

USFS Rocky Mountain Research Station

322 E. Front Street, Suite 401

Boise, ID 83702

208.373.4360, Fax 208.373.4391

nancylshaw@fs.fed.us

Francis Kilkenny, Research Biologist

USFS Rocky Mountain Research Station

322 E. Front Street, Suite 401

Boise, ID 83702

208.373.4376, Fax 208.373.4391

ffkilkenny@fs.fed.us 

~~~~-

~~~~~~~~-
SEED INCREASE

187

Holly Prendeville, Research Geneticist

USFS Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7300

hollyrprendeville@fs.fed.us

Brad St Clair, Research Geneticist

USFS Pacific Northwest Research Station

3200 SW Jefferson Way

Corvallis, OR 97331-4401

541.750.7294

bstclair@fs.fed.us

Anne Halford, Restoration Ecologist

DOI BLM Idaho State Office

1387 S. Vinnell Way

Boise, ID 83709

208.373.3940

ahalford@blm.gov

Project Description

Seed was to be increased of selected Great Basin native forbs and grasses for restoration research 

projects. During the last year seed was increased for bluebunch wheatgrass (Pseudoroegneria 

spicata) and winterfat (Krascheninnikovia lanata).

Introduction

Bluebunch wheatgrass (Pseudoroegneria 

spicata) and winterfat (Krascheninnikovia 

lanata) are important forage species for 

both livestock and wildlife in the 

intermountain West. Commercial releases 

of bluebunch wheatgrass have not proven 

to be adapted to all Great Basin 

environments. The use of specifically 

adapted ecotypes could be an important 

advance to ensure successful range 

restorations. The current project efforts 

seek to increase seed of different ecotypes 

of bluebunch wheatgrass selected by the 

U.S. Forest Service in the Great Basin and 

to increase seed of winterfat for the BLM 

from Snake River Birds of Prey National 

Conservation Area in Idaho.

Figure 1. Harvested seed stalks of bluebunch wheatgrass. 

Malheur Experiment Station, Oregon State University, 

Ontario, OR.
SEED INCREASE

188

Materials and Methods

Selections of bluebunch wheatgrass from eight seed zones in the southern sagebrush steppe Great 

Basin region were planted at the Malheur Experiment Station in Ontario, OR on June 4, 2014. The 

selections from each seed zone were planted in individual plots with four 30-inch rows which were 20 

feet long. Seedlings were planted 12 inches part in the rows. The plots were located 200 feet apart. 

Each row was irrigated with one drip tape laid on the soil surface. On March 6, 2015, 50 lb N/acre and 

50 lb of P/acre were broadcast on the soil 

surface. The timing of seed maturity varied 

between individual plants within each plot. 

At each harvest, seed from all plants with 

mature seed within a plot was harvested 

(Figure 1, Table 1). Seed from each harvest 

from each plot was kept separate. On October 

23, 2015 an additional eight selections from 

8 additional seed zones were planted. These 

selections were from seed zones in the 

northern part of the Great Basin. Plots for this

planting were smaller, having 2 rows 10 to 20 

feet long. The selections planted were: N1, 

N3a, N4, N5, N6a, N6b, N7a, and N7b. The 

selections were watered manually twice after 

planting. On January 13, 2016, 50 lb N/acre 

was broadcast on the soil surface. On January 

13, 2016, 50 lb N/acre was broadcast on the 

soil surface. 

Winterfat seeds were received in March 2014 

and planted into cell trays in a greenhouse. 

The seedlings were planted with 12-inch 

spacing in 30-inch rows on April 29, 2014. 

Four rows approximately 300 feet long were 

planted. Each row was irrigated with one drip 

tape laid on the soil surface. Seed was 

harvested in the fall of 2014 and given to the 

BLM at the Snake River Birds of Prey 

National Conservation Area. A few grams of 

seed from 2014 was retained and was sown 

in the greenhouse in the winter of 2014/2015 

to provide seedlings for expanding the 

planting to four 400 feet long rows. The seedlings were transplanted in March of 2015. Seed was again 

harvested in the fall of 2015.

Results

The amounts of bluebunch wheatgrass seed harvested from each selection for each harvest date are 

listed in Table 1.

Selection Harvest date

Uncleaned seed 

weight, g

S2A 11-Jun 85.6

26-Jun 900.0

14-Jul 152.3

total 1137.8

S3A 12-Jun 34.4

26-Jun 2131.5

total 2165.9

S4 26-Feb 320.9

26-Jun 602.6

14-Jul 53.4

total 976.9

S5 26-Jun 1034.4

14-Jul 58.4

total 1092.8

S6A 26-Jun 784.6

14-Jul 31.7

total 816.4

S6B 348.9

26-Jun 1058.9

14-Jul 336.7

total 1744.4

S7B 23-Jun 203.9

26-Jun 1286.4

14-Jul 13.6

total 1504.0

Table 1. Amount of raw uncleaned seed harvested from 

bluebunch wheatgrass in 2015 from each seed zone 

selection by harvest date. Malheur Experiment Station, 

Oregon State University, Ontario, OR.
189

SPECIES INTERACTIONS
SPECIES INTERACTIONS

190

Project Title Drought Effects on the Symbiosis Between Wyoming Big 

Sagebrush Seedlings and Arbuscular Mycorrhizal Fungi

Project Agreement No. 14-JV-11221632-014

Principal Investigators and Contact Information 

Marcelo D. Serpe, Professor 

Department of Biological Sciences

Boise State University

1910 University Drive

Boise, ID, 83725-1515

208.426.3687

mserpe@boisestate.edu

Project Description

Introduction

Arbuscular mycorrhizal fungi (AMF) are obligate biotrophs that facilitate nutrient uptake in 

exchange for organic carbon (Smith et al. 2010). Traditionally, the plant-AMF symbiosis has been 

considered mutualistic (Finlay 2008). However, various results indicate that the symbiosis can range 

from mutualistic to parasitic depending on the plant-fungus genotype involved in the association and 

environmental conditions (Klironomos 2003, Jones and Smith 2004). During severe drought, plants 

close their stomata, which limits carbon uptake. Under these conditions, AMF could become 

parasitic if the host plant cannot exclude the fungus (Auge 2004, Augé et al. 2014). We investigated 

this possibility in Artemisia tridentata spp. wyomingensis (Wyoming big sagebrush) seedlings 

inoculated with AMF spores of Rhizophagus irregularis. 

Objectives

1) Determine total AMF colonization and the abundance of different mycorrhizal structures 

after drought-induced stomatal closure. 

2) Analyze whether drought affects the type of symbiosis that develops between Wyoming 

big sagebrush seedlings and R. irregularis. 

Methods

The above objectives were investigated by conducting a completely randomized mesocosm 

experiment consisting of two inoculation treatments (non-inoculated and inoculated seedlings) and 

two watering regimens (well-watered and water-stressed seedlings). Initially, Wyoming big sagebrush 

seeds were germinated in rockwool cubes soaked in a hydroponic solution. After roots emerged from 

the cubes, seedlings were transplanted to 2 L cone-tainers filled with 1:1 sand:vermiculite mix. At this 

time, the roots were treated with water for the non-inoculated treatment or a suspension containing 

200 spores of R. irregularis for the inoculated treatment. These spores were obtained from in vitro

cultures of this fungus growing in Ri T-DNA transformed carrot roots (Becard and Fortin 1988). After 

transplanting to the cone-tainers, seedlings were grown in a greenhouse under a 15 h photoperiod and 

day/night conditions of 20/15 ± 3 °C. The soil was maintained at field capacity for four weeks 
SPECIES INTERACTIONS

191

following transplanting. Subsequently some 

seedlings were kept well-watered, while 

others experienced a gradual and terminal 

drought imposed by withholding water from 

the pots. The effects of drought on the 

seedlings were monitored weekly by 

measuring stomatal conductance and 

photosynthetic electron transport (ETR) with 

a leaf porometer and a modulated chlorophyll 

fluorometer, respectively. When waterstressed plants showed negligible stomatal 

conductance and electron transport, waterstressed and well-watered plants were 

sampled and analyzed for the presence of 

different mycorrhizal structures and overall 

AMF colonization. AMF colonization was 

determined by the intersection method after 

staining with Chlorazol black E (McGonigle 

et al. 1990). For water-stressed seedlings, 

survival curves were also constructed based 

on the time at which the seedlings showed 

ETR values below 5 μmol m-2s

-1

. At this 

time, leaves were still green, but the 

seedlings did not recover photosynthetic 

capacity after rewatering indicating

hydraulic failure and death. Statistical 

differences were evaluated based on a lorank 

test.

Results and Discussion

After 5 weeks of withholding water, stomatal conductance began to decline in water-stressed plants 

and after 15 weeks of this treatment, stomatal conductance was negligible (Fig. 1). No differences in 

stomatal conductance were detected between control and AMF-inoculated plants. Independent of the 

watering regimen, no colonization was observed in non-inoculated seedlings (data not shown). In

contrast, inoculated seedlings had total colonization values above 50% (Fig. 3A). This was observed 

at the time at which withholding watering was initiated (initial) and at the time when seedlings were 

harvested for final measurement of colonization. At this time, no differences in total and arbuscular 

colonization were apparent between well-watered and water-stressed seedlings (Fig. 3A and B). In 

contrast, vesicles were more abundant in well-watered than in water-stressed seedlings (Fig. 3C). Few 

spores were detected within the roots and their presence was not affected by the watering regimen 

(Fig. 3D). Although the percent of root length occupied by hyphae and arbuscules were similar in wellwatered and water-stressed seedlings, root growth was higher in well-watered plants (Fig. 4A). Thus, 

water stress reduced AMF growth within the roots, but just in proportion to the reduction in root 

growth.

Figure 1. Changes in stomatal conductance of noninoculated (control) and AMF-inoculated seedlings. 

Symbols represent means (± standard errors) of 5 

measurements for the well-watered seedlings and 20 

measurements for the water-stressed ones. Water stress 

also decreased ETR (Fig. 2A). However, ETR was not 

affected by the inoculation treatment. Under water 

stress, ETR tended to be lower in inoculated than 

control seedlings; but for most of the days measured, 

the differences were not significant (Fig. 2A). As water 

stress continued, individual seedlings showed a rapid 

decline in ETR to zero (Fig. 2B), which was 

irreversible.
SPECIES INTERACTIONS

192

Figure 3. Mycorrhizal colonization of inoculated seedlings at the time of the last watering in water 

stressed plants (Initial), 20 weeks after this time in well-watered seedlings (MWW), and when electron 

transport was negligible in water-stressed seedlings (MWS). Bars represent means (± SE) of 6 to 10 

seedlings. Means not labeled by the same letter are significantly different (p < 0.05). 

A B

Figure 2. A, Average values of electron transport rates (ETR) for control well-watered (CWW), 

inoculated well-watered (MWW), control water-stressed (CWS), and inoculated water-stressed (MWS) 

sagebrush seedlings. B, Representative curves showing the rapid and final declined in ETR in three 

individual seedlings. Symbols in A represent means (± SE) of 5 measurements for the well-watered 

seedlings and 20 measurements for the water-stressed ones.
SPECIES INTERACTIONS

193

Overall, the results indicate that after closing their stomata due to severe drought, Wyoming big 

sagebrush seedlings remained colonized by AMF. Under these conditions, the seedlings were 

presumably not gaining carbon, while some carbon was likely needed to maintain the AMF. The 

presence of arbuscules, in particular, suggests that some exchange of nutrients occurred after stomatal 

closure. Arbuscules have rapid turnover and consequently it is unlikely that they represented nonactive structures remaining from earlier colonization (Alexander et al. 1989, Vierheilig et al. 2005). 

Transfer of carbon to the fungus without a carbon gain by the plant would have led to a parasitic 

symbiosis (Jones and Smith 2004). This notion found support in the results from the survival analysis. 

After 91 days without watering survival was higher in inoculated than non-inoculated seedlings (p = 

0.004, Fig. 4B). However, this trend was reversed as the period without watering lengthened. When 

only the survival that occurred after 91 days was considered, survival was higher in non-inoculated 

than inoculated seedlings (p = 0.005). As result of these two opposite trends, no significant differences 

in survival were detected between non-inoculated and inoculated seedlings at the end of the experiment 

(p = 0.4). The results from the survival analysis are, however, preliminary. This analysis was based on 

only 20 seedlings per treatment; experiments with a larger number of seedlings are needed to ascertain 

the survival patterns observed.

Management Applications

Inoculation of seedlings with AMF is a common practice aimed at improving seedling establishment 

(Allen 1989, Turnau and Haselwandter 2002, Navarro Garcia et al. 2011). The success of this 

practice depends on the formation of a mutualistic symbiosis between the plant and the fungus. 

However, several factors can affect the nature of this symbiosis. Our preliminary data suggests that 

under severe water stress, the association of Wyoming big sagebrush seedlings with R. irregularis

became parasitic. To alleviate this problem, additional management practices may be needed. In this 

regard, a possibility would be to utilize nurse plants (Padilla and Pugnaire 2006). Through a 

common mycorrhizal network, the larger, nurse plant would provide an alternative source of carbon 

to the AMF reducing their dependence on the young seedlings (Selosse et al. 2006). In addition, it is 

Figure 4. Effects of AMF colonization on root growth (A) and survival (B) of 

Wyoming big sagebrush seedlings. In A, bars represent means (± SE) of 5 seedlings 

for the well-watered treatments (CWW and MWW) and 20 seedlings for the waterstressed ones (CWS and MWS). Means not labeled by the same letter are significantly 

different (p < 0.05).
SPECIES INTERACTIONS

194

plausible that the ability of sagebrush to exclude AMF under drought depends on the particular AMF 

involved in the association (Klironomos 2000; Finlay 2008). Although R. irregularis is common in 

sagebrush ecosystems (Carter et al. 2014), the particular strain that we used is not native to 

sagebrush habitats. The use of a native inoculum may result in a different response than the one 

observed, where the seedlings are able to exclude the fungus under severe water deficits. Current 

work is aimed at testing this notion. 

Presentations

Velasco, J.; Smith, J. F.; Serpe, M. D. 2015. Drought effects on colonization of Artemisia tridentata

seedlings by arbuscular mycorrhizal fungi. Botanical Society of America annual meeting; 25-29 

July; Edmonton, Alberta.

Abstract: Arbuscular mycorrhizal fungi (AMF) are obligate biotrophs that facilitate nutrient uptake 

in exchange for organic carbon. Traditionally, the plant-AMF symbiosis has been considered 

mutualistic. However, various results indicate that the symbiosis can range from mutualistic to 

parasitic depending on the plant-fungus genotype involved in the association and environmental 

conditions. During severe drought, plants close their stomata, which limits carbon uptake. Under 

these conditions, AMF could become parasitic if the host plant cannot exclude the fungus. We 

investigated this possibility in Artemisia tridentata seedlings inoculated with AMF spores of 

Rhizophagus irregularis. Seedlings were initially grown under well-watered conditions. 

Subsequently some seedlings were kept well-watered, while others experienced a gradual and 

terminal drought. The effects of drought on the seedlings were monitored weekly by measuring 

stomatal conductance and photosynthetic electron transport. When water-stressed plants showed 

negligible stomatal conductance and electron transport, water-stressed and well-watered plants were 

sampled and analyzed for AMF colonization. Total AMF colonization was 62 (±13) and 67 (±17) % 

for well-watered and water stressed plants, respectively. Similarly, arbuscular colonization was 27 (±

4) and 27 (±11) % for well-watered and water-stressed plants. The lack of significant differences in 

total and arbuscular colonization between well-watered and water stressed plants indicates that A. 

tridentata seedlings did not exclude R. irregularis under drought. This may lead to a parasitic 

symbiosis under severe water stress.

Davidson, B. E.; Smith, J. F.; Serpe, M. D. 2015. Community structure of arbuscular mycorrhizal 

fungi colonizing Artemisia tridentata seedlings following inoculation and transplanting. Botanical 

Society of America annual meeting; 25-29 July; Edmonton, Alberta. [Poster]

Abstract: Inoculation of seedlings with arbuscular mycorrhizal fungi (AMF) can alter the AMF taxa 

present in the roots after transplanting. This may occur even when native AMF is used as the 

inoculum because the environmental conditions and hosts that are used for AMF multiplication are 

different from those in natural habitats. The effect of inoculation on AMF composition was 

investigated in seedlings of Artemisia tridentata ssp. wyomingensis inoculated with native AMF. 

Seedlings were first grown in a greenhouse in sterilized soil (non-inoculated seedlings) or soil 

containing a mixture of native mycorrhizal species (inoculated seedlings). Three-month old 

seedlings were transplanted outdoors to 24 L pots filled with soil from a sagebrush habitat or to a 

recently burned sagebrush habitat. At the time of transplanting the percent colonization was 

negligible for non-inoculated seedlings and ranged between 24 to 81% for the inoculated ones. 

Three, 5, or 8 months after transplanting colonization was about twofold higher in inoculated than 

non-inoculated seedlings. To characterize the effect of inoculation on the AMF community, DNA 

was extracted from the roots and amplified with AMF specific primers. The AMF taxa were 

characterized based on sequences from the LSU-D2 rDNA region. A total of 6 phylotypes were 
SPECIES INTERACTIONS

195

identified, two within the Claroideoglomeraceae and four within the Glomeraceae. In addition, 

sequences were grouped into operational taxonomic units (OTUs) with sequence similarities higher 

than 94%. This resulted in the identification of 29 OTUs. Ordination analyses, using non-parametric 

multidimensional scaling, indicated that inoculation did not alter the structure of the AMF 

community. Individual seedlings, regardless of inoculation treatment, were simultaneously colonized 

by AMF belonging to 3 to 6 OTUs. The lack of significant differences in AMF communities among 

inoculation treatments appeared to have been related to the predominance of certain OTUs. In all 

experiments and treatments, four OTUs were dominant. Overall, the results indicate that the 

inoculum generated from native AMF contributed to the colonization of roots that developed after 

transplanting, resulting in higher levels of colonization than those naturally occurring in the soil 

without altering the AMF community. 

Serpe, M. D.; Davidson, B. E. 2015. Improvement in colonization and seedling survival of Wyoming 

big sagebrush seedlings following inoculation with native arbuscular mycorrhizae. National Native 

Seed Conference; 13-16 April; Santa Fe, New Mexico.

Davidson, B. E.; Serpe, M. D. 2015. Community structure of arbuscular mycorrhizal fungi 

colonizing Wyoming big sagebrush seedlings transplanted to the Snake River Birds of Prey, NCA. 

Great Basin Consortium Conference; 17-19 February; Boise, Idaho.

Publications

Davidson, B. E. 2015. Consequences of pre-inoculation with native arbuscular mycorrhizae on root 

colonization and survival of Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) 

seedlings after transplanting. Boise, ID: Boise State University. 104 p. Thesis. 

References

Alexander, T.; Toth, R.; Meier, R.; Weber, H. C. 1989. Dynamics of arbuscule development and 

degeneration in onion, bean, and tomato with reference to vesicular–arbuscular mycorrhizae in 

grasses. Canadian Journal of Botany 67: 2505–2513.

Allen, E. B. 1989. The restoration of disturbed arid landscapes with special reference to mycorrhizal 

fungi. Journal of Arid Environments 17: 279–286.

Augé, R. M. 2004. Arbuscular mycorrhizae and soil/plant water relations. Canadian Journal of Soil 

Science 84: 373–381.

Augé, R. M.; Toler, H. D.; Saxton, A. M. 2014. Arbuscular mycorrhizal symbiosis alters stomatal 

conductance of host plants more under drought than under amply watered conditions: a metaanalysis. Mycorrhiza 25(1): 13-24.

Becard, G.; Fortin, J. A. 1988. Early events of vesicular arbuscular mycorrhiza formation on Ri TDNA transformed roots. New Phytologist 108: 211–218. 
SPECIES INTERACTIONS

196

Carter, K. A.; Smith, J. F.; White, M. M.; Serpe, M. D. 2014. Assessing the diversity of arbuscular 

mycorrhizal fungi in semiarid shrublands dominated by Artemisia tridentata ssp. wyomingensis. 

Mycorrhiza 24(4): 301–314.

Finlay, R. D. 2008. Ecological aspects of mycorrhizal symbiosis: with special emphasis on the 

functional diversity of interactions involving the extraradical mycelium. Journal of Experimental 

Botany 59: 1115–1126. 

Jones, M. D.; Smith, S. E. 2004. Exploring functional definitions of mycorrhizas: are mycorrhizas 

always mutualisms? Canadian Journal of Botany 82: 1089–1109.

Klironomos, J. N. 2000. Host-specificity and functional diversity among arbuscular mycorrhizal 

fungi. In: Bell, C. R.; Brylinsky, M.; Johnson-Green, P., eds. Microbial biosystems: new frontiers, 

8

th International Symposium on Microbial Ecology. Halifax, Canada: 845–851.

Klironomos, J. N. 2003. Variation in plant response to native and exotic arbuscular mycorrhizal 

fungi. Ecology 84: 2292–2301.

McGonigle, T.; Miller, M.; Evans, D. 1990. A new method which gives an objective measure of 

colonization of roots by vesicular—arbuscular mycorrhizal fungi. New Phytologist 115: 495–501.

Navarro Garcia, A.; Banon Arias, S. P.; Morte, A.; Sanchez-Blanco, M. 2011. Effects of nursery 

preconditioning through mycorrhizal inoculation and drought in Arbutus unedo L. plants. 

Mycorrhiza 21: 53–64. 

Padilla, F. M.; Pugnaire, F. I. 2006. The role of nurse plants in the restoration of degraded 

environments. Frontiers in Ecology and the Environment 4: 196–202.

Selosse, M. A.; Richard, F.; He, X.; Simard, S. W. 2006. Mycorrhizal networks: des liaisons 

dangereuses? Trends in Ecology and Evolution 21: 621–628. 

Smith, S. E.; Facelli, E.; Pope, S.; Smith, F. A. 2010. Plant performance in stressful environments: 

interpreting new and established knowledge of the roles of arbuscular mycorrhizas. Plant Soil 326: 

3–20.

Turnau, K.; Haselwandter, K. 2002. Arbuscular mycorrhizal fungi, an essential component of soil 

microflora in ecosystem restoration. In: Gianinazzi S.; Schüepp H.; Barea J. M.; Haselwandter, K., 

eds. Mycorrhizal Technology in Agriculture. Verlag, Switzerland: Birkhäuser Basel: 137–149.

Vierheilig, H.; Schweiger, P.; Brundrett, M. 2005. An overview of methods for the detection and 

observation of arbuscular mycorrhizal fungi in roots. Physiologia Plantarum 125: 393–404. 
SPECIES INTERACTIONS

197

Project Title Comprehensive Assessment of Restoration Seedings to 

Improve Restoration Success

Project Agreement No. 15-JV-11221632-197

Principal Investigators and Contact Information 

Kari E. Veblen, Assistant Professor

Utah State University

5230 Old Main Hill

Logan, UT 84322-5230

435.797.3970, Fax 435.797.3796

kari.veblen@usu.edu

Thomas Monaco, Ecologist

USDA-ARS Forage and Range Res. Lab.

Utah State University

Logan, Utah 84322-6300

435.797.7231, Fax 435.797.3075

Other collaborators

Jason Vernon, Danny Summers, Kevin Gunnell (Great Basin Research Station), Eric Thacker 

(USU), Joe Robins (USDA-ARS) 

Project Description

Introduction

Restoration projects rely on seedling establishment and persistence to foster invasion resistance and 

improve resilience to environmental stress and disturbance (James et al. 2010; Chambers et al. 

2014). However, few studies have comprehensively evaluated the landscape-level performance of 

seeded species or the factors that control their short-term establishment and long-term persistence 

(Hardegree et al. 2011; Knutson et al. 2014). Assessing the role of these factors across physiographic 

regions that experience high temporal and spatial variability in environmental conditions will reveal 

the effectiveness of various pre-seeding land treatments and enhance our capacity to select 

appropriate restoration species for specific ecological sites based on their seeding establishment and 

persistence.

The Utah Watershed Restoration Initiative (WRI) is a collaborative effort among landowners, and 

state and federal agencies with the goal of enhancing wildlife habitat, biological diversity, and water 

resources by manipulating vegetation at large scales (http://wildlife.utah.gov/ watersheds/). From the 

WRI database, we identified 99 sagebrush and 68 conifer-encroached (i.e., pinyon-juniper) 

restoration sites along gradients in elevation (1250-2500 m) and annual precipitation (200-500 mm) 

in the Great Basin, Colorado Plateau, and Rocky Mountain physiographic provinces. Prior to 

seeding, sites were treated with prescribed fire and/or various other treatments to reduce woody fuels 
SPECIES INTERACTIONS

198

and foster the growth of existing herbaceous vegetation and seeded species. Sites were seeded using 

broadcast, drill, or aerial techniques to restore a diverse array of grass, forb, and shrub species. 

Given this assortment of sites, restoration treatments, and seeded species, we propose to assess the 

relative success of seeded grass, forb, and shrub species as part of an ongoing effort to determine 

environmental and ecological factors controlling sagebrush ecosystem restoration. 

Objectives

Specific project objectives are to 1) determine the separate and combined effects of soils, 

environmental parameters, restoration treatments, and seeding techniques on plant species 

establishment and persistence, 2) decipher the association between plant species traits and seedling 

establishment and persistence in the field, and 3) quantify the cost effectiveness and efficiency of 

these seeding efforts. 

Methods

Detailed vegetation monitoring has been conducted at WRI sites before and at various intervals after 

applying restoration/seeding treatments. In the first year of this project we will compile cover and 

density data and assess species establishment and persistence with respect to environmental 

parameters, restoration treatments, and seeding techniques. We will use effect-size analysis (e.g., log 

response ratio of pre/post species cover and density). Effect sizes can either be positive or negative, 

depending on whether a species established or failed, respectively. This technique is ideal for 

analysis of disparate sites and treatment years. 

We also will characterize soil properties (texture, pH, organic matter) using the USDA web soil 

survey (http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm), environmental parameters 

(precipitation and temperature variables, slope, aspect) using PRISM climate data 

(http://www.prism.oregonstate.edu), and wildlife/livestock impacts using information contained in 

WRI reports to assess their influence on seeding success (Obj. 1). We also will characterize species 

by the traits prioritized during development of plant materials as well as life form, growth form and 

phenological pattern, tolerance to grazing and drought, and seeding rate to decipher their association 

with seeding success (Obj. 2). Finally, we will calculate treatment and seeding costs from WRI 

reports and quantify the cost effectiveness and efficiency of each seeding project (Obj. 3). 

Expected Results and Discussion

This project will assess the success of restoration plant materials over a broad range of ecological 

sites throughout Utah. Our assessment will provide critical information to compare the cost 

effectiveness of restoration treatments and seeding. Our effort will also quantitatively assess the 

performance of species based on biological traits, which can be used to enhance plant material 

development and influence seeding success over both short and long-term periods. This project will 

provide land managers with information to restore their rangeland with revegetation projects. We 

have already shared preliminary results at the Utah Division of Wildlife Resources/Utah State 

University Brown Bag Luncheon Seminar Series.
SPECIES INTERACTIONS

199

References

Chambers, J. C.; Bradley, B. A.; Brown, C. S.; D' Antonio, C.; Germino, M. J.; Grace, J. B. 2014. 

Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert 

shrublands of western North America. Ecosystems 17: 360-75.

Hardegree, S. P.; Jones, T. A.; Roundy, B. A.; Shaw, N. L.; Monaco, T. A. 2011. Assessment of 

range planting as a conservation practice. In: Briske, D. D., ed. Conservation benefits of rangeland 

practices: assessment, recommendations, and knowledge gaps. Lawrence, KS: Allen Press: 171-212. 

James, J. J.; Svejcar, T. 2010. Limitations to postfire seedling establishment: the role of seeding 

technology, water availability, and invasive plant abundance. Rangeland Ecology and Management 

63: 491-5.

Knutson, K. C. ; Pyke, D. A.; Wirth, T. A.; Arkle, R. S.; Pilliod, D. S.; Brooks, M. L.; Chambers, J. 

C.; Grace, J. B. 2014. Long-term effects of seeding after wildfire on vegetation in Great Basin 

shrubland ecosystems. Journal of Applied Ecology 51: 1414-1424.
SPECIES INTERACTIONS

200

Project Title Impacts of Climate Change and Exotic Species to Native 

Plant-Microbial Interactions

Project Agreement No. 15-JV-11221632-190

Principal Investigators and Contact Information

Kevin C. Grady, Assistant Research Professor

School of Forestry

Northern Arizona University

200 E. Pine Knoll Dr.

Flagstaff, AZ, 86011

480.254.8620, Fax 928.523.1080

kevin.grady@nau.edu

Co- Investigators Paul Dijkstra, Assistant Research Professor

Center for Ecosystem Science and Society

Northern Arizonian University

PO Box 5620

Flagstaff, AZ 86011

928.523.8344, Fax 928.523.0565

Paul.Dijkstra@nau.edu

Catherine Gehring, Professor/Microbial Ecologist

Department of Biological Sciences

617 S. Beaver St.

PO Box 5640

Flagstaff, AZ 86011

928.523.9158, Fax 928.523.7500

Catherine.Gehring@nau.edu

Egbert Schwartz, Professor/Microbial Ecologist

Department of Biological Sciences

617 S. Beaver St.

PO Box 5640

Flagstaff, AZ 86011

928.523.6168, Fax 928.523.7500

Egbert.Schwartz@nau.edu
SPECIES INTERACTIONS

201

Hillary Cooper, Graduate Student/Plant Ecologist

Department of Biological Sciences

617 S. Beaver St.

PO Box 5640

Flagstaff, AZ 86011

928.523.2381, Fax 928.523.7500

hfc5@nau.edu

Project Description

Introduction

Restoration of Great Basin native plant communities and their associated communities of animals 

and microorganisms is increasingly difficult due to the combined impacts of climate change and 

exotic species invasions. Local maladaptation from increasing aridity constrains the use of locallysourced germplasm in restoration efforts (Breed et al. 2012). Subsequently, it has become 

increasingly evident that restoration efforts should include germplasm that is best-suited to a range 

of future environmental conditions, especially a more arid climate (Jones and Monaco 2009, Breed 

et al. 2012). Studies that test phenotypic responses to a range of environmental conditions using 

germplasm sourced from multiple provenances is an important first step towards testing the 

feasibility of assisted migration initiatives for restoration in current and future environments (Wang 

et al. 2010).

In addition to assisted migration of key native plants as part of restoration, simultaneous transfer of 

co-evolved community interactions may be important to maximize restoration success. For instance, 

there is growing evidence that facilitative interspecific plant interactions among foundation plant 

species are under selection (Martin and Harding 1981, Thorpe et al. 2011, Grady et al., in review). 

Maintaining facilitative plant interactions may be especially important for restoring ecosystems 

during a time of climate change and exotic plant invasion (Suttle et al. 2007, Crutsinger et al. 2008). 

Recent research also indicates that intra-specific interactions may be facilitative via maternal affects 

or kinship recognition (Callaway and Mahall 2007, Dudley and File 2007). One approach to study if 

plant interactions have evolved is to compare fitness of inter- and intraspecific competition pairs 

between plants that have either a sympatric (i.e., sourced from the same location/population) or 

allopatric neighbor (i.e., sourced from a different location). A fitness advantage from growing next 

to a sympatric neighbor indicates an evolved interaction, generally due to either evolved niche 

differentiation or facilitation. 

In addition, exotic species often modify soil properties, disrupt beneficial relationships between 

native plants and soil microbes, and even promote invasion of other exotics (Jordan et al. 2008, 

Schaeffer et al. 2011). Revegetation efforts and natural regeneration of natives can be limited by the 

absence of these beneficial microorganisms (Meinhardt and Gehring 2012). While most current 

assisted migration programs focus on single species, restoration programs that include co-evolved 

interacting species across multiple trophic dimensions (e.g., from plants to micro-organisms) may 

increase restoration effectiveness. Understanding this community genetic “interactome” is critical 

for advancing restoration practice and theory during rapid environmental change.
SPECIES INTERACTIONS

202

Objectives

We propose to investigate the importance of maintaining community interactions for restoration 

using a common garden provenance approach. This research will build upon current research in 

which we are investigating the effectiveness of adding live and commercial soil microbial inoculum 

during revegetation of Artemisia tridentata, Elymus elymoides, and Achnatherum hymenoides with 

and without competition by Bromus tectorum at three common gardens (Mountain Home, Idaho; 

west Salt Lake, Nevada; Fredonia, Arizona). Our group includes experts in plant and microbial 

genomics and the application of genomic approaches for restoration. 

We will expand one of the three common gardens that we have developed to include a plant genetic 

by community interaction experiment to test the following hypotheses: 1) Genetic variation across 

the thermal range of A. tridentata and A. hymenoides is correlated to past climate such that plants are 

locally adapted, 2) Competition with exotic species reduces plant fitness and exacerbates 

maladaptation due to climate change, 3) Inoculation with locally adapted soil microbes will decrease 

the negative impacts of competition with exotic species, 4) Both intra- and inter-specific plant 

interactions are less competitive when plants are grown with sympatric neighbors (i.e., sourced from 

the same location) compared to allopatric neighbors (i.e., sourced from different locations), 

especially in the presence of exotic species, and 5) Sympatric benefits are greatest when inoculated 

with soil microbes, together reducing negative impacts from maladaptation and exotic species. 

Taken together, this study will increase our knowledge of both abiotic and biotic adaptations and the 

importance of both to restoration.

Methods

Common Garden Establishment

Our study will focus on one common garden at the core of the distribution of both A. tridentata and 

A. hymenoides. This common garden is located west of Salt Lake City on the Hill Airforce Base with 

a mean minimum January temperature of -7° C, a mean maximum July temperature of 32° C and 

annual precipitation of 165 mm. At the site, we have installed fencing to reduce browsing, a 4,000 

gallon (15,141 L) water tank and irrigation lines, and a weather station. This infrastructure was 

established for ongoing research sponsored by a grant from the Department of Defense (DoD). This 

previously funded grant creates a synergy with GBNPP as we have established garden infrastructure, 

coordination with local groups that can help with planting and watering, we have already collected 

germplasm that can be used in this experiment, and we have analyzed DNA of soil microbes in the 

experimental garden and in the live soil inoculum. The DoD grant did not include a genetic 

component nor a native plant interaction experiment.

Experimental Design

From prior research, we have collected seeds from nine separate locations for A. tridentata and A. 

hymenoides. In each of three regions (southern Idaho, central Utah, and northern Arizona), we have 

collected seeds from three populations across an elevation gradient, with each population separated 

by approximately 300 meters in elevation. At the common garden, we will plant greenhouse-grown 

seedlings into three blocks of each of the following four treatments for a total of 12 blocks: 1) live 

soil inoculation, exotic species competition, 2) no inoculation, exotic species competition, 3) live 

soil inoculation, no exotic species competition, and 4) no inoculation, no competition. Each garden is 

located in a cheatgrass-infested field. The no competition treatment will be created by hand removal 

of B. tectorum. Soil inoculation treatments include collecting live soil inoculum from a local source 
SPECIES INTERACTIONS

203

(within 1km from the garden) from the rhizosphere underneath either A. tridentata or A. hymenoides. 

We will evaluate population variation in response to climate, inoculation, and competition with B. 

tectorum by planting nine seedlings from each of nine populations for each species in each of 12 

blocks for a garden total of 1,944 plants. 

We will evaluate if plants benefit from sympatric neighbors (either intra- or interspecific), and if 

these benefits increase in the presence of exotic species and with microbial inoculation. In two 

blocks from each of the four treatments described above, we will plant six intra-specific sympatric 

pairs (12 plants) from three populations (one from each region: ID, UT, AZ) for each species; 12 

intra-specific allopatric pairs (24 plants) for each species; six inter-specific sympatric pairs (12 

plants) from each of three populations; 12 inter-specific allopatric pairs (24 plants).

Measurements

We will measure growth (height, canopy diameter, diameter at root collar, aboveground biomass), 

survival, plant physiological traits (specific leaf area, leaf nitrogen content), and determine fungal 

communities and infection rate using microscopy approaches.

Statistical Procedures

We will compare among treatments using a combination of analysis of variance and restricted 

maximum likelihood procedures at both the block level (n=3 for population variation among nine 

populations) and at the individual plant level (n = 27 per population); or for sympatric/allopatric 

comparison at the plant pair level (n = 18 allopatric pairs or 36 individuals and n = 12 sympatric 

pairs or 24 individuals).

 

References

Breed, M. F.; Stead, M. G.; Ottewell, K. M.; Gardner, M. G; Lowe, A. J. 2012. Which provenance 

and where? Seed sourcing strategies for revegetation in a changing environment. Conservation 

Genetics 14: 1-10.

Callaway, R. M.; Mahall, B. E. 2007. Family Roots. Nature 448: 145-147.

Crutsinger, G. M.; Souza, L.; Sanders, N. J. 2008. Intraspecific diversity and dominant genotypes 

resist plant invasions. Ecology Letters 11: 16–23.

Dudley, S. A.; File, A. L. 2007. Kin recognition in an annual plant. Biology Letters 3: 435-438.

Grady, K. C.; Wood, T.; Kolb, T. E.; Shuster, S. M.; Gehring, C. A.; Whitham, T. G. 2015. 

Interactions among foundation tree species lead to local biotic adaptation. Proceedings of the 

National Academy of Sciences. (In review). 

Jones, T. A.; Monaco, T. A. 2009. A role for assisted evolution in designing native plant materials 

for domesticated landscapes. Frontiers in Ecology and the Environment 7: 541–547.

Jordan, N. R.; Larson, D. L.; Huerdm S. C. 2008. Soil modification by invasive plants: effects on 

native and invasive species of mixed-grass prairies. Biological Invasions 10(2): 177-190.
SPECIES INTERACTIONS

204

Martin, M. M.; Harding, J. 1981. Evidence for the evolution of competition between two species of 

annual plants. Evolution 35: 975–987.

Meinhardt, K. A.; Gehring, C. A. 2012. Disrupting mycorrhizal mutualisms: a potential mechanism 

by which exotic tamarisk outcompetes native cottonwoods. Ecological Applications 22: 532-549.

Schaeffer, S. M.; Ziegler, S. E.; Belnap, J.; Evans, R. D. 2011. Effects of Bromus tectorum invasion 

on microbial carbon and nitrogen cycling in two adjacent undisturbed arid grassland communities. 

Biogeochemistry 115: 427-441.

Suttle, K. B.; Thomsen, M. A.; Power, M. E. 2007. Species interactions reverse grassland responses 

to changing climate. Science 315: 640-642.

Thorpe, A. S.; Aschehoug, E. T.; Atwater, D. Z.; Callaway, R. M. 2011. Interactions among plants 

and evolution. Journal of Ecology 99: 729-740.

Wang, T.; O’Neill, G. A.; Aitken, S. N. 2010. Integrating environmental and genetic effects to 

predict responses of tree populations to climate. Ecological Applications 20: 153–163.
205

 SCIENCE DELIVERY 
SCIENCE DELIVERY

206

Project Title Science Delivery for the Great Basin Native Plant Project

Project Agreement No. 14-JV-11221632-018

Principal Investigators and Contact Information 

Corey Gucker, Outreach Coordinator

Corey Gucker Company

416 N. Garden St.

Boise, Idaho 83706

208.373.4342

coreylgucker@fs.fed.us

Project Description

Science integration and science application are integral to the success of the Great Basin Native 

Plant Project (GBNPP). Completed studies in the areas of plant material development, cultural 

practices for seed production, and restoration ecology and technology provide a constantly 

increasing body of knowledge that is published and distributed in many ways: published in journals, 

theses and dissertations, reports, presented through posters, brochures, flyers, disseminated through 

e-mail and meeting networking. Sharing and synthesizing this information is essential to rapid and 

appropriate application in the selection of appropriate plant materials for planting mixes, commercial 

seed production, and ecological restoration.

Objectives

The objectives of this project are to promote timely, useful, and user-friendly information to GBNPP 

cooperators and collaborators to advance successful Great Basin restoration efforts.

Results and Discussion

Accomplishments related to the identification and sharing of GBNPP scientific developments 

include: 

 Maintaining contact with Great Basin Native Plant Program (GBNPP) cooperators through 

regular correspondence, event alerts, and communication of project due dates. 

 Updating and producing hard copy posters and brochures for Great Basin events and 

meetings. 

 Regularly updating the GBNPP website with meeting announcements, new publications, and 

updated cooperator information.

 Helping to develop the agenda and secure presenters for the annual GBNPP meeting.

 Tracking and reporting GBNPP accomplishments.
SCIENCE DELIVERY

207

Project Title SeedZone Mapper Smartphone App Development

Project Agreement No. 13-IA-11221632-161

Principal Investigators and Contact Information

Andrew Bower, Area Geneticist

Olympic National Forest

1835 Black Lake Blvd SW

Olympia, WA 98502 

360.956.2405 

abower@fs.fed.us

Charlie Schrader-Patton, Senior Analyst/Developer

Remote Sensing Applications Center

1657 NW John Fremont 

Bend, OR 97701

541.312.4291

cschrader@fs.fed.us

Project Description

Introduction

Generalized provisional seed zones were developed by Bower et al. (2014) to guide seed movement 

for native species for which no information is available regarding genetic variation for traits 

important to adaptation. These provisional seed zones were based on climatic data and are 

increasingly being used when making collections of seed as foundation seed for farm field increase 

or for direct sowing in restoration plantings. The provisional seed zones are available as 

downloadable GIS shapefiles and are also contained in an interactive web map on the SeedZone 

mapper website (available at http://www.fs.fed.us/wwetac/threat_map/SeedZones_Intro.html), part 

of the Western Wildlands Environmental Threat Assessment Center’s (WWETAC) Wildland Threat 

Mapper. Land managers, contractors, and restoration practitioners have indicated the usefulness of 

these web-based resources, but these platforms are usually not available for use in the field when an 

internet connection is not available. 

Objectives

Develop a smartphone (iOS and Android) app that would allow anyone with a smartphone or tablet 

device to utilize their devices on-board GPS to determine the provisional seed zone at their location 

even if a cell signal is not available. The app would show the user the seed zone that they are 

currently located in, along with a scrollable and zoomable map that would allow the user to 

determine the proximity of adjacent seed zones, and view other base map layers such as roads, 

contours, and land ownership. 
SCIENCE DELIVERY

208

Methods

An ESRI/Leaflet browser app was developed as a prototype to test proof-of-concept for the 

smartphone app (http://fs.bioe.orst.edu/web_maps/Seed_Zones.html). Leaflet is a lightweight library 

that is responsive and is compatible for many devices from PC’s to tablets to phones (iOS, Android). 

The simple interface allows the user to access their location and get a popup with the seed zone. This 

is where we want to go with the app, but need to configure it for off-line use. This product is being 

researched further and is a solution that remains on the table.

Development and programming of smartphone apps has become a competitive and expensive 

business. “Off –the-shelf” solutions are available, but often they do not meet all the needs of a 

specific project. We have researched a number of products, including Fulcrum, ESRI (Collector, 

Explorer) Avenza PDF maps, MapBox, and a few others. As expected, each application does well in 

some areas, but poorly in others.

We have contacted Digital Visions (a USFS enterprise team) who developed a proposal for app 

development, but it did not meet our objectives. We also have engaged with the CIO mobile apps 

group, but at this time they are working on infrastructure to brand and distribute mobile apps, not 

develop them.

A strong contender is the S1 Mobile App (http://www.blm.gov/or/gis/mobile/s1mobile/) developed 

jointly for the Bureau of Land Management/USFS Region 6 in Oregon. This powerful product may 

meet our needs with some modifications and we are currently exploring this as an avenue for a final 

product. 

Expected Results and Discussion

A list of desired features for the smartphone app has been compiled, and includes:

1. Android and iOS usability.

2. Off-line functionality.

3. Pop-up with the seed zone parameters.

4. Ability to host locally on the device the CONUS seed zone layer.

5. Ability to host a variety of tiled basemaps – imagery, topos, agency-specific maps, roads.

6. Easy updating of the app (basemaps, etc.) when in a connected environment.

7. No USFS firewall issues, i.e. no datasets that are internal only.

8. Ability to collect geospatial data (i.e. contractor collects a point with quantity and species 

of seed collected, date, slope, aspect, etc.).

An app that includes these features will allow land managers and seed collectors (both agency and 

contractors) to easily access and use the provisional seed zones while in the field (in an off-line 

environment). This will improve efficiency and effectiveness of activities such as seed collection, 

seed movement decision-making, restoration planning, and project implementation.

References

Bower, A. D.; St. Clair, J. B.; Erickson, V. E. 2014. Generalized provisional seed zones for native 

plants. Ecol. Apps. 25: 913-919.
209

CRESTED WHEATGRASS 

DIVERSIFICATION
CRESTED WHEATGRASS DIVERSIFICATION

210

Project Title Presence of Native Vegetation in Crested Wheatgrass 

(Agropyron cristatum) Seedings and the Influence of 

Crested Wheatgrass on Native Vegetation

Project Agreement No. 11-IA-11221632-003

Principal Investigators and Contact Information

Kirk Davies Rangeland Scientist

United States Department of Agriculture

Agricultural Research Service

67826-A Hwy 205 

Burns, Oregon 97720

541.573.4074, Fax 541.573.3042

Kirk.Davies@oregonstate.edu 

Aleta Nafus Graduate Research Assistant

United States Department of Agriculture

Agricultural Research Service

67826-A Hwy 205 

Burns, Oregon 97720

541.573.4074, Fax 541.573.3042

Aleta.Nafus@oregonstate.edu

Project Description

Objectives

The objectives of our study were to 1) determine vegetation successional trajectories of native 

perennial bunchgrasses that were co-planted with crested wheatgrass and whether they persist in the 

community, and 2) determine the variability in native vegetation presence in stands of crested 

wheatgrass and determine what factors (management, site/environmental characteristic, etc.) are 

associated with native plant recruitment in crested wheatgrass plant communities.

Methods

We sampled 120 crested wheatgrass plant communities in southeastern Oregon between May and 

August 2012, and June and September 2013 to investigate which factors promote native plant 

recruitment in crested wheatgrass plant communities. At each plot slope, aspect, elevation and UTM 

location were recorded. 

Sites were selected with input from Bureau of Land Management professionals to represent a wide 

range of management practices such as: timing (spring or fall), intensity (distance to water/fence 

lines) of grazing, range of time since seeding, and other environmental factors (elevation, aspect and 

slope, and proximity to untreated areas). 
CRESTED WHEATGRASS DIVERSIFICATION

211

To sample vegetation, 60 x 50 m plots were used to sample each site. In each plot, four 50 m 

transects were deployed at 20 m intervals along the 60 m transect. Along each transect, herbaceous 

vegetation basal cover and density were visually estimated by species inside 40 x 50 cm frames 

located at 3 m intervals on each transect line (starting at 3 m and ending at 45 m), resulting in 15 

frames per transect and 60 frames per plot. Ground cover (bare ground, rock, litter and crypto-biotic 

crust) were measured in the 40 x 50 cm frames. Shrub canopy cover by species was measured by 

line intercept. Canopy gaps less than 15 cm were included in the canopy cover measurements. Shrub 

density was determined by counting all individuals rooted in four 2 x 50 m belt transects at each 

plot. 

Soil samples were collected at three locations in each plot with a 61 cm (24 in) hole located at the 

center of the plot and at 15 m NW and SE of the center of the plot. From each of these holes soil 

samples were taken from 0-15 cm, from 0-20.3 cm (0-8 in), and from 20.3-61 cm (8-24 in). Depth to 

hardpan was recorded if it fell within the 61 cm (24 in). The values for each of the samples per plot 

were averaged into a single plot value. Soil texture for the 0-8 inch and 8-24 inch samples was 

measured using the hydrometer method. The 0-15 cm samples were used to obtain soil pH, nitrogen, 

carbon, and total organic matter for each site.

Actual use data for sites was collected whenever available and for the maximum time period 

available. Disturbance, precipitation, and seeding history are collected for each site when possible.

Results and Discussion

Annual forbs occurred in 93%, annual grasses in 89%, Sandberg bluegrass (Poa secunda) in 85%, 

shrubs in 81%, native perennial forbs in 75%, and large native perennial bunchgrasses (LNPB) in 

59%, of the 121 sites sampled. All sites contained at least one native species. Average herbaceous 

perennial species diversity was 0.6 + 0.05. Total species richness, including shrub and herbaceous 

species, was between 2 and 37 species with an average of 13.2 + 0.8. Squirreltail (Elymus elymoides)

was the most common LNPB, occurring on 35% of the sites. Wyoming big sagebrush (Artemisia

tridentata spp. wyomingensis) was the most common shrub and occurred on 63% of the sites. LNPB 

and Wyoming big sagebrush occurred together on 49% of the sites while LNPB, sagebrush and 

perennial forbs occurred together on 39% of the sites. 

Basal cover and density varied widely among and within herbaceous functional groups (Fig. 1 & 2, 

respectively).

Plant community composition of crested wheatgrass stands was quite variable. Though nearmonoculture of crested wheatgrass existed, some stands had large quantities of native vegetation, 

especially shrubs. Correlations between environmental variables and vegetation characteristics 

suggest that some of the variability in the abundance of native vegetation in crested wheatgrass 

stands is likely caused by environmental differences. Big sagebrush was the most common native 

species in stands of crested wheatgrass.

Environmental factors explained as little as 0% of the variability in annual grass density and as much 

as 56% of the variability of large bunchgrass density. Perennial forb basal cover, annual grass and 

Sandberg bluegrass (Poa secunda) basal cover and density variability were also well explained (43-

46%) by environmental factors.
CRESTED WHEATGRASS DIVERSIFICATION

212

Though a variety of environmental factors were included in regression models, soil texture appeared 

to be quite important. Soil texture was included in the best regression models for cover and density 

of all plant functional groups. 

Figure 1. Boxplot showing the percent basal cover of Sandberg bluegrass (POSA), crested 

wheatgrass (AGDE), large native perennial bunchgrass (LNPB), perennial forbs (PF), annual grass 

(AG), annual forbs (AF) and foliar cover (%) of shrubs across 121 crested wheatgrass stands 

sampled in southeastern Oregon. The median is shown as the solid black line, the mean is depicted 

as a grey cross. The upper and lower ends of the box correspond to the first and third quartiles (the 

25th and 75th percentiles). Whiskers extend from the 25th and 75th percentiles to the lowest or 

highest value that is within 1.5 * the inter-quartile range. Data beyond the end of the whiskers are 

outliers and plotted as points (as specified by Tukey).

Figure 2. Boxplot showing density (plants.m

-2

) of Sandberg bluegrass (POSA), crested 

wheatgrass (AGDE), large native perennial bunchgrass (LNPB), perennial forbs (PF), 

annual grass (AG), annual forbs (AF) and shrubs across 121 crested wheatgrass stands 

sampled in southeastern Oregon. The median is shown as the solid black line, the mean is 

depicted as a grey cross. The upper and lower ends of the box correspond to the first and 

third quartiles (the 25th and 75th percentiles). Whiskers extend from the 25th and 75th

percentiles to the lowest or highest value that is within 1.5 * the inter-quartile range. Data 

beyond the end of the whiskers are outliers and plotted as points (as specified by Tukey).
CRESTED WHEATGRASS DIVERSIFICATION

213

Large native perennial bunchgrass group (LNPB) was the least likely functional group to occur in 

crested wheatgrass communities we sampled across southeastern Oregon. Although 10% of our 

sampled sites had a higher density of native perennial bunchgrasses than crested wheatgrass, we 

found, overall, few LNPB in most stands of crested wheatgrass. This likely confounded our ability to 

find meaningful associations between LNPB and environmental factors. LNPG basal cover and 

density were negatively correlated with sandy soil.

Perennial forbs density and basal cover were, similarly to large native perennial bunchgrasses, lower 

on sandy soil. 

Annual forbs, annual grasses, and Sandberg bluegrass were the three most prevalent herbaceous 

functional groups in stands of crested wheatgrass and all tend to avoid resource limitations by 

growing early in the season when resources are more plentiful. 

Wyoming big sagebrush constituted the majority of the shrub cover and density measurements. 

Similarly to Davies et al. (2007), we did not find a strong correlation between Wyoming big 

sagebrush density, cover, and other measured environmental variables. Our data does suggest that, in 

agreement with Davies et al. (2006, 2007) and in contrast to Williams (2009), Wyoming big 

sagebrush was negatively correlated with more sandy soils. Plant communities with higher numbers 

of shrubs, most of which were Wyoming big sagebrush, tended to be associated with soils higher in 

silt and lower in precipitation. However, associations were relatively weak as only 25% of the 

variation in Wyoming big sagebrush density was explained by environmental variables. Therefore, 

soil texture may not have much effect on the likelihood of sagebrush reestablishment into crested 

wheatgrass seedings. Although the relationship was not strong, there was a negative correlation 

between crested wheatgrass basal cover and Wyoming big sagebrush foliar cover (adj. R2 = 0.26, p < 

0.001). However, there did not appear to be a relationship between Wyoming big sagebrush and 

crested wheatgrass density (R2 < 0.10, p > 0.05).

Though we could only explain a small portion of the variability in Wyoming big sagebrush density 

and cover, it occurred on 63% of the seedings. Wyoming big sagebrush recovery after disturbance 

can be slow, often taking several decades to a century (Watts and Wambolt 1996; Baker 2006; Boyd 

and Svejcar 2011). Thus, having 15% of the seedings have 10% or higher sagebrush cover suggests 

that sagebrush recovery can occur and provide habitat for sagebrush associated wildlife species. At 

10% sagebrush cover these seedings meet the minimal sagebrush cover requirements suggested by 

Connelly et al. (2000) for Greater sage-grouse (Centrocercus urophasianus) winter habitat. 

Similarly, McAdoo et al. (1989) reported that sagebrush associated species reoccupied crested 

wheatgrass seedings after sagebrush reestablished. 

Most communities seeded to crested wheatgrass were degraded, burned in a wildfire and/or treated 

to remove shrub species prior to seeding, thus the limited native vegetation at some sites may have 

been an artifact of plant community composition at the time it was seeded. The type and severity of 

disturbance, as well as plant composition prior to seeding, is likely to affect current plant 

composition on the site (Burke and Grime 1996). 

Sagebrush cover and density were negatively correlated with precipitation in the year after seeding 

and the interaction between precipitation and fire and was positively correlated with seeding age and 
CRESTED WHEATGRASS DIVERSIFICATION

214

time since fire (adj. R

2 = 0.34 and 0.34, p < 0.001). 

Sandberg bluegrass, perennial forb, and shrub 

density varied by pre-seeding treatment/disturbance. 

These results suggest that pre-seeding 

treatment/disturbance and precipitation following 

seeding significantly influence the plant community 

characteristics of crested wheatgrass stands.

Large native perennial bunchgrass density and basal 

cover (Fig. 3) were 20- to 30-times greater in grazed 

compared to ungrazed crested wheatgrass seedings 

(p = 0.01 and 0.01). Sagebrush density and cover 

(Fig. 3) was 16- and 14-fold greater in the grazed 

compared to ungrazed crested wheatgrass stands. 

Density and cover (Fig. 3) of other native plant 

groups were also greater in grazed compared to 

ungrazed crested wheatgrass plant seedings. Grazing 

appears to reduce the competitiveness of crested 

wheatgrass and thereby allows a greater expression 

on native vegetation in crested wheatgrass stands. 

Future Plans

We will be preparing the final manuscript with 

plans to submit to Rangeland Ecology & 

Management. We also will be revising as needed 

the manuscript submitted to Journal of Arid 

Environments. We will be presenting some of our 

findings at the Society for Range Management 

Meetings in Texas in February 2016.

Management Applications 

Our data suggests that there are some 

environmental factors, especially related to soil 

texture, that influence plant community composition of crested wheatgrass seedings regardless of 

management and initial floristics. Our results also suggest that the effects of seeding crested 

wheatgrass likely vary considerably by site characteristics and that native vegetation can co-occupy 

some rangelands seeded with crested wheatgrass. This information may be useful for prioritizing 

where restoration of sagebrush communities seeded with crested wheatgrass should be applied, and 

assessing potential effects of seeding crested wheatgrass. Pre-seeding treatment/disturbance and postseeding precipitation also influences plant community dynamics of crested wheatgrass stands. Postseeding management (e.g. grazing) appears to influence community composition of crested wheatgrass 

stands. 

 

Figure 3. Basal cover (%) of Sandberg bluegrass, 

crested wheatgrass, and large native perennial 

bunchgrasses (LNPB) and foliar cover (%) of 

shrubs and Wyoming big sagebrush on crested 

wheatgrass seedings that were grazed (n = 6) or 

ungrazed (n = 6). Grazed and ungrazed sites had 

similar soil texture, location, seeding age, and 

time since fire. Functional groups and species 

were compared using Wilcoxon rank sums and 

were significantly different at p < 0.05.
CRESTED WHEATGRASS DIVERSIFICATION

215

Presentations

Davies, K. W.; Nafus, A. M.; Svejcar, T. J. 2015. Vegetation characteristics of crested wheatgrass 

stands vary by seeding year precipitation, disturbance history, and management. Society for 

Rangeland Management Meeting; 2015 February; Corpus Christi, TX. 

Publications 

Nafus, A. M.; Svejcar, T. J.; Ganskopp, D. C.; Davies, K. W. 2015. Abundances of co-planted native 

bunchgrasses and crested wheatgrass after 13 years. Rangeland Ecology & Management 68: 211-

214.

Nafus, A. M. 2015. Association between crested wheatgrass and native vegetation in southeastern 

Oregon. An investigation of co-establishment, environment, seeding history, and livestock 

management. Corvallis, OR: Oregon State University. 105 p. Dissertation.

Nafus, A. M.; Svejcar, T. J.; Davies K. W. [In review]. Environmental characteristics associated 

with native vegetation variability in introduced bunchgrass stands. Journal of Arid Environments.

Nafus, A. M.; Svejcar, T. J.; Davies K. W. [In preparation]. Prior disturbance history, management,

and seeding year precipitation associations with vegetation characteristics of crested wheatgrass 

stands. Rangeland Ecology & Management.

References

Baker, W. L. 2006. Fire and restoration of sagebrush ecosystems. Wildlife Society Bulletin 34: 177-

185.

Boyd, C. S.; Svejcar, T. J. 2011. The influence of plant removal on succession in Wyoming big 

sagebrush. Journal of Arid Environments 75: 734-741.

Burke, M. J. W.; Grime, J. P. 1996. An experimental study of plant community invisibility. Ecology 

77: 776.

Connelly, J. W.; Schroeder, M. A.; Sands, A. R.; Braun, C. E. 2000. Guidelines to manage sage 

grouse populations and their habitats. Wildlife Society Bulletin 28: 967-985.

Davies, K. W.; Bates, J. D.; Miller, R. F. 2006. Vegetation characteristics across part of the 

Wyoming big sagebrush alliance. Rangeland Ecology & Management 59: 567-575.

Davies, K. W.; Bates, J. D.; Miller, R. F. 2007. Environmental and vegetation characteristics of the 

Artemisia tridentata spp. wyomingensis alliance. Journal of Arid Environments 70: 478-494.

McAdoo, J. K.; Longland, W. S.; Evans, R. A. 1989. Nongame bird community responses to 

sagebrush invasion of crested wheatgrass seedings. The Journal of Wildlife Management 53: 494-

502.
CRESTED WHEATGRASS DIVERSIFICATION

216

Watts, M. J.; Wambolt, C. L. 1996. Long-term recovery of Wyoming big sagebrush after four 

treatments. Journal of Environmental Management 46: 95-102.

Williams, J. R. 2009. Vegetation characteristic of Wyoming big sagebrush communities historically 

seeded with crested wheatgrass in northeastern Great Basin. Logan, UT: Utah State University. 89 p. 

Thesis.
217

RESTORATION STRATEGIES
RESTORATION STRATEGIES

218

Project Title Herbicide Impacts on Forb Performance in Degraded 

Sagebrush Steppe Ecosystems 

Project Agreement No. 14-CR-11221632-067

Principal Investigators and Contact Information

Marie-Anne de Graaff, Assistant Professor 

Department of Biological Sciences 

Boise State University

1910 University drive

Boise, ID 83725

208.426.1256, Fax 208.426.1515

marie-annedegraaff@boisestate.edu

Project description

Invasion of sagebrush ecosystems by cheatgrass (Bromus tectorum) leads to loss of ecosystem 

structure and function. Restoration efforts are required to re-attain an intact native plant community. 

Restoration treatments can include: mowing, herbicide applications, a combination of mowing and 

herbicide applications, and grazing; but if these treatments promote soil resource availability they 

may further reduce the resistance of the ecosystem to invasion. Further, herbicide applications may 

negatively impact native vegetation, with cascading effects on other native populations such as sage 

grouse (Centrocercus urophasianus). 

This study aimed to: 

1. Assess how mowing, grazing and herbicide treatments impact soil microbial activity and soil 

nitrogen (N) availability.

2 . Evaluate the impact of imazapic on forbs native to the sagebrush steppe ecosystem by:

( a ) Quantifying how different application rates (concentrations) affect forb 

performance. 

( b ) Determining how the timing of imazapic application relative to seeding of forbs

impacts forb performance.

( c ) Measuring whether a fire-induced change in soil microbial activity mediates the 

impact of imazapic on soils. Results indicated that mowing, herbicide applications, 

a combination of mowing and herbicide applications, and grazing do not impact 

soil microbial activity and alter soil nutrient availability if abiotic conditions, such 

as drought, limit biological processes in semi-arid ecosystems.

Imazapic applications significantly impacts performance of B. tectorum, as well as performance of 

native forbs (A. filipes, A. millefolium, and S. grossularifolia) regardless of concentration and timing 

of application. This suggests that imazapic is not specific to cheatgrass, and that the use of imazapic 

could negatively impact native vegetation that are essential to the survival of sage grouse. Although 

imazapic negatively impacted A. filipes, A. millefolium, and S. grossularifolia performance, the 

response of A. filipes to imazapic applications was significantly less negative than that of the other 
RESTORATION STRATEGIES

219

species, indicating a need for additional studies to evaluate how plant functional types may mediate 

impacts of imazapic on their performance.

Introduction

Disturbance of native plant communities by invasive non-native plant species is a global problem, 

because invasion leads to reduced plant diversity, ecosystem function, and ecosystem services 

(Chapin et al. 2002). In the intermountain west of North America, invasion of the winter annual 

cheatgrass (Bromus tectorum) has significantly altered the native Wyoming big sagebrush (Artemisia 

tridentata ssp. wyomingensis) ecosystem (e.g., Knapp 1996). Cheatgrass has invaded thousands of 

square kilometers, accounting for about 20 percent of the historic sagebrush-bunchgrass 

communities, and in those areas cheatgrass accounts for almost 100 percent coverage (Knapp 1996). 

The spread of cheatgrass has reduced the ecosystem’s fire regime from 60-110 years (Whisenant 

1990) to 3-5 years (D’Antonio and Vitousek 1992), thus exacerbating its impact on ecosystem 

structure and function. Wyoming big sagebrush is a shrub that was distributed on more than 60 

million hectares in the western region of North America (West 1983) and as a foundation species 

(Prevey et al. 2010) it provides valuable habitat for other native plant and animal species, such as 

sage grouse (Centrocercus urophasianus) and pygmy rabbits (Brachylagus idahoensis) (Busby 

2011). While cheatgrass is able to recover quickly after a fire, the short fire return interval prevents 

the recovery and re-establishment of native plant species. Consequently, restoration efforts are 

necessary to re-attain an intact native plant community.

Cheatgrass invasion may be suppressed with a suite of management tools including mowing, grazing 

and herbicide applications, but whether these treatments lead to the desired restoration outcomes 

remains questionable (Pyke et al. 2013). To improve our understanding of these types of 

management tools on ecosystems, restoration projects could benefit from an explicit recognition of 

treatment-induced changes in plant-soil feedbacks (Kardol and Wardle 2010). Namely, fuel 

reduction treatments – mowing and grazing in particular – can alter plant-soil feedbacks by 

increasing soil resources, thereby inadvertently promoting growth of the plant species that’s most 

likely to invade (Prevey et al. 2010). Resource availability in soils is a key variable that can explain 

the potential success of restoration treatments because, according to ecological theory, native plants 

fare best when resources are adequately depleted (e.g., Tilman et al. 1997); and vice versa, increases 

in resource availability in space or time can reduce resistance to invasion by cheatgrass in native 

plant communities (Prevey et al. 2010). Thus quantifying impacts of restoration treatments on the 

processes that drive soil nutrient availability will improve our understanding of the effectiveness of 

restoration projects.

The pre-emergent herbicide imazapic, which kills plants by inhibiting the production of branched 

chain amino acids, can be an effective herbicide for cheatgrass control but it may negatively impact 

native species (Baker et al. 2009). To date, contrasting results have been generated about its impact 

on performance of non-target species, such as forbs native to the sagebrush steppe ecosystem that are 

essential for sage grouse survival (Shinn and Thill 2002, 2004; Kyser et al. 2007; Baker et al. 2009). 

The impact of imazapic on non-target species may hinge on the amount of imazapic applied to the 

system and on its persistence in the soil from where it can affect plant growth. Imazapic persistence 

in the soil depends on imazapic degradation rates which are primarily driven by the soil microbial 

community (Grymes et al. 1995). Imazapic has an average half-life in soil of 120 days (Grymes et al. 

1995) but, in dry lands, such as a semi-arid desert, microbial activity is frequently limited by water 

availability, which may prolong the predicted half-life time of imazapic in soil. Further, these soils 
RESTORATION STRATEGIES

220

are frequently subjected to fire, which can impact the soil microbial community and its activity (Hart 

et al. 2005), thus potentially changing the decay rate of imazapic.

Methods

Field Experiment

To evaluate how different restoration methods may impact soil microbial activity and N 

mineralization, a manipulative field experiment was conducted on a loam soil at the Morley Nelson 

Birds of Prey National Conservation Area (BOP-NCA) in southwestern Idaho (lat. 43°13'50"N, long. 

116°19'20"W). The historical plant community was dominated by A. tridentata subsp. wyomingensis

and secondarily by A. tridentata subsp. tridentata, but multiple fires (with the last fire occurrence in 

1987) and past land use eliminated them from the study area and much of the surrounding landscape. 

Before the experimental treatments, the plant community was dominated by cheatgrass, a non-native 

tumble-mustard (Sisymbrium altissimum L), and Sandberg’s bluegrass (Poa secunda J Presl, an early 

seral perennial). Experimental plots (1 ha) located within three large replicate blocks were treated 

with a full-factorial, completely randomized combination of fuel reduction/native plant restoration 

treatments: mowing, mowing + herbicide, herbicide application, and control (no treatment), with half 

of all plots grazed by sheep (12.8 ac/AUM) in 2013, while the other half was not grazed. Herbicide 

plots were prep- mowed in April 2012, and mowing-only and mowing + herbicide plots were mowed 

in May 2012. Mowing was to 10 cm stubble height using a tractor-pulled rotomower. Herbicide 

plots received 280 g ha–1 of glyphosate with a boomless sprayer without surfactant in April 

2012 following mowing, and then 280 g ha–1 of imazapic with Hasten surfactant via a calibrated 

boom sprayer in October 2012 (for more site information see also: Brabec et al. 2015).

In June of 2014 (two years following initiation of the experiment), we collected soil samples from 

field plots that received the following treatments: (1) herbicide applications, (2) mowing, (3) a 

combination of mowing and herbicide applications, and (4) control (i.e., receiving no treatments). 

Each one of these plots was either grazed or not grazed, and these plots were not seeded. We 

collected ten subsamples of soil across each plot (5 cm depth) using an Edelman Combination Auger 

(http://www.ams-samplers.com). Following collection, subsamples were composited into one 

sample, such that we obtained one composite sample per treatment across the replicates (n=3). 

Immediately upon sampling the individual soil cores were composited, sieved to 2 mm, and visible 

roots >2 mm in length were removed. Soils were stored at 6°C for approximately 2 weeks.

We conducted a 60 day controlled laboratory incubation study with the soils to evaluate the impact 

of the treatments on potential C decomposition rates. The soil (40 g dry weight) was incubated for 90 

days in 1 L Mason jars containing four 50 ml centrifuge tubes filled with 10 g soil each. Temperature 

was maintained at 20° C, and soil moisture was kept at 60% of water holding capacity. Soil waterholding capacity was determined by the difference in weight for soils at saturation and at oven dry 

(100° C), and water was added as needed during the experiment to maintain a soil moisture content 

of 60% saturation. Further, 5 mL of water was added to the bottom of each jar to prevent soil drying. 

The mason jars were tightly sealed, and a septum in the jar lid allowed gas samples to be removed 

from the headspace with a 10 mL syringe. Soil CO2 evolution was measured on days 1, 3, 7, 15, 30, 

and 60 of the incubation. Following each gas sampling event, the caps were removed and the jars 

were flushed with air for 30 minutes. Respiration rates were analyzed on four sub-samples per 

replicate using a LI-7000 infrared gas analyzer (IRGA, LICOR Corp., Lincoln, NE). Nitrogen 

mineralization was measured using a potential N mineralization assay. Soils were extracted with 2M 

KCl on days 0, 7, 15, 30 and 60. We analyzed the concentration of NO3 via manual vanadium (III) 

reduction, and the concentration of NH4 using a Berthelot reaction (Forster, 1995).
RESTORATION STRATEGIES

221

Greenhouse Experiment

To assess how imazapic applications may affect the 

performance of native forb species: milkvetch (Astragalus 

filipes), common yarrow (Achillia millefolium), and 

Gooseberryleaf globemallow (Sphaeralcea grossularifolia), we 

conducted two greenhouse experiments in which we: (1) 

applied a gradient of imazapic concentrations (hereafter ‘the 

imazapic concentration experiment’), and (2) varied the timing 

of application (hereafter ‘the imazapic application timing 

experiment’) relative to seeding of the forbs (Fig. 1). Soils were 

collected in degraded recently burned and unburned sagebrush 

ecosystems (0-10 cm depth) at the Morley Nelson Birds of

Prey National Conservation Area. The soil was air-dried for 7 

days, litter and roots were removed by using a 2 mm sieve, and kept under dry conditions at 20-23°C 

until ready for planting. A fifteen day laboratory incubation with the soil was performed to confirm

that the fire had altered microbial activity in the recently burned soil, compared to the unburned soil. 

Soils from each treatment were placed in 1 L mason jars, then incubated in the dark for 15 days under 

controlled soil moisture (60% WHC) and temperature (20° C) conditions. The mason jars were

tightly sealed with a septum in the jar lid which allowed gas samples to be removed from the 

headspace with a 10 mL syringe. Soil CO2 evolution was measured on days 1, 3, 7, and 15 of the

incubation. Following each gas sampling event, the caps were removed and the jars were flushed

with air for 30 minutes. Respiration rates were analyzed on four sub-samples per replicate using a 

LI-7000 infrared gas analyzer (IRGA, LICOR Corp., Lincoln, NE)

The imazapic concentration experiment was set up as a complete 

randomized block design (n=10) (Fig. 3). Imazapic concentrations of 0 g ha1 a.i., 140 g ha-1 a.i., 280 g ha-1 a.i., and 560 g ha-1 a.i. with 1% Hasten 

surfactant were applied evenly to pots two weeks prior to planting forbs. 

Pots (6.4 cm diameter and 12.7 cm depth) were lined with a nylon sack (Fig. 

2) filled with cleaned rocks and covered with 250 g of the burned and 

unburned soil. Soil was watered evenly to 60% water holding capacity. 

Forbs were planted after the seeds were germinated according to their 

specific germination requirements (Table 1). The seeds were planted with 

equal spacing (Fig. 3) and the pots were randomized every three weeks. 

Plants were grown at 15° C-25° C for 41 days. 

For reparation of the imazapic application timing experiment, burned and 

unburned soils were composited and transferred to pots in a similar fashion as 

described above. Imazapic (280 g ha-1 a.i. plus 1% Hasten surfactant), or water 

containing 1% Hasten surfactant, but no imazapic, was added by spray to all 

of the pots. A. millefolium, A. filipes, S. grossulariifolia, and Bromus tectorum

(n=10) were planted after 2, 4, 8, or 16 weeks. The plants were watered daily 

and kept at optimal conditions in the greenhouse. Soils waiting to be planted 

were maintained under the same conditions and watered 3 times weekly. After 

the plants grew for 41 days, height was recorded and the foliage was harvested. 

Plants were dried at 40° C for 24 hours, and weighed for aboveground biomass quantification. The 

soils were frozen at -20° C until belowground biomass could be processed. Live roots were removed 

from the soil, washed and dried in the oven for 40° C for 24 hours, after which they were weighed.

Figure 1. Greenhouse experiment.

Figure 2. Pot preparation.

Figure 3. Seed Spacing. 
RESTORATION STRATEGIES

222

Table 1. Germination protocol.

Forb Scarify Stratify Surface 

Sterilize

Plant depth

Astragalus 

filipes

220 grit sandpaper for 

3 minutes (50 seeds X

8)

NO NO 3.5 mm

Achillia 

millefolium

NO NO NO 0 mm

Sphaeralcea 

grossularifolia

18 M H2SO4 for 10 

min (200 seeds X 4)

3/15/13- 4/29

Refrigerated (~5°C) 

in petri dishes on 

moist filter paper for 

7 weeks

NO 6.5 mm

Bromus 

Tectorum

NO NO NO Light dusting

Statistical Analyses

To evaluate how fuel reduction treatments in the field impacted CO2 respiration and N 

mineralization rates, two-way ANOVA’s were conducted with treatments (i.e., grazing and fuel 

reduction treatments) as fixed effects, using the Univariate GLM in SPSS Statistics 17.0. We 

conducted three-way ANOVA’s using the Univariate GLM in SPSS Statistics 17.0 for the imazapic 

concentration experiment using burning, plant species, and imazapic concentration treatments as 

fixed effects. We used two way ANOVA’s with imazapic application timing experiment. For all 

ANOVAs, means were compared by the Tukey test, after confirmation that the ANOVA was 

significant. The level of significance was P < 0.05.

Results and discussion

Field Experiment

Mowing, herbicide applications, a combination of both treatments, and grazing had no effect on soil 

microbial CO2 respiration (Fig. 4) or N mineralization (Figs. 5a and b). These data contradict 

observations showing positive effects of similar management activities on soil resource availability 

(Chambers and Wisdom 2009). However, effects of mowing and grazing both are mediated by 

abiotic conditions (Wardle et al. 2004), and our study site was subjected to considerable drought 

conditions while management activities were ongoing (Brabec et al. 2015). These conditions likely 

contributed to the limited the response of the soil microbial community to the fuel reduction 

treatments.
RESTORATION STRATEGIES

223

Greenhouse Experiment

Burning significantly affected soil 

microbial activity (p < 0.05); recently 

burned soils had a greater content of 

labile C leading to greater resource 

availability for soil microbes and 

greater CO2 respiration rates 

compared to soils that were not burned 

(Fig. 6). These data indicate that 

changes in the soil microbial 

community occurred following a fire

and these changes may impact decay 

rates of imazapic and hence its impact 

on forb performance. However, 

although we found that imazapic 

application significantly suppressed 

biomass production for each of the 

forb species (p<0.05, n=10; Fig. 7 and 

Fig. 8a-c), burning did not mediate the 

response of forbs to imazapic 

applications. These data either indicate 

that burning did not lead to a change in 

microbial activity that was sufficiently 

large to impact imazapic degradation, or 

that fire may impact soil microbial 

strains that are not actively involved in 

the degradation of imazapic. In 

agricultural settings it has been 

observed that degradation of herbicides 

is controlled only by specific microbial 

strains, thus herbicide application itself 

rather than fire induced changes in the 

microbial community, may impact 

herbicide degradation rates in soil 

(Huang et al., 2009).

The magnitude of the response to 

mazapic application differed among 

species. We calculated the response as 

the percent change in biomass 

production relative to the control (i.e., 

no imazapic application), where a 

greater response signifies a greater sensitivity of the forb to imazapic. The average response of above 

(Fig. 9a) and belowground (Fig. 9b) biomass production was significantly different (p < 0.05) across 

forb species (n=20). Specifically, the response of A. filipes was affected by imazapic applications the 

least.

Figure 4. Cumulative microbial CO2 respiration (μg C/g 

soil DW) from soils exposed to a variety of fuel reduction 

treatments and grazing. Values are means + SE (n=3).

Figure 5. Net N mineralization from soils to a variety of 

fuel reduction treatments without (5a) and with (5b) 

grazing. Values are means + SE (n=3).
RESTORATION STRATEGIES

224

Since fire had no impact on imazapic effects 

on forb performance, we did not include the 

burned soils in the second greenhouse 

experiment where we focused on the timing 

of imazapic application to forbs relative to 

seeding. In addition, we included B. tectorum

to ascertain if any impacts of imazapic on 

forb performance also impact B. tectorum

growth. For each one of the forbs, biomass 

production in control soils (i.e., soils not 

receiving imazapic) was greater when plants 

were seeded into soil at a later date. In 

contrast, this trend was not observed in soils 

receiving imazapic application (Fig. 10a-d). 

Increased biomass production in control 

soils likely resulted from the multiple 

irrigation events that promoted soil organic 

matter decomposition and the release of 

nutrients in soil over time. Our results 

further indicate that imazapic applications negatively impacted biomass production of A. millefolium, 

S. grossulariifolia, and B. tectorum regardless of application timing (Fig 10a-d), with the response of 

B. tectorum being greater than that of the other two forbs across treatments. 

Figure 6. Impact of fire on soil microbial activity. Different letters indicate significant 

differences in CO2 respiration between burned and unburned soils. Values are means 

+ SE (n=5).

Figure 7. Visual differences in forb performance 

across species exposed to different concentrations of 

imazapic application.
RESTORATION STRATEGIES

225

Additionally, there were some differences in 

the magnitude of response to imazapic 

application for each one of the forb species 

relative to our first greenhouse experiment, 

where the response was generally greater in the 

first compared to the second experiment. Since 

our two greenhouse experiments were 

conducted during two different seasons (i.e., the 

first experiment was conducted during the 

summer, while the second experiment was 

conducted during the winter months), we 

attribute any differences in the magnitude of 

response of forbs to imazapic applications to 

differences in abiotic conditions, most notably 

light conditions. Interestingly, performance of 

A. filipes was not negatively impacted by 

imazapic applications in the ‘timing of 

imazapic application experiment’. This result is 

in agreement with the results of our first 

greenhouse experiment (i.e., the imazapic 

concentration experiment) where A. filipes had 

a significantly lower response to imazapic 

applications than the other forb species. A 

major difference between A. filipes versus the 

other forb species is that A. filipes is a legume. 

These data indicate that legumes may mediate 

the impact of imazapic applications on their 

performance. Additional research is required to 

ascertain that different plants functional types 

respond differently to imazapic applications.

Management Applications and/or Seed 

Production Guidelines

Fuel load reduction treatments (i.e., mowing, 

herbicide applications, a combination of 

mowing and herbicide applications, and 

grazing) may not impact soil microbial activity 

and alter soil nutrient availability if abiotic 

conditions, such as drought, limit biological processes in semi-arid ecosystems. Imazapic 

applications significantly impacts performance of B. tectorum, as well as performance of native forbs 

(A. filipes, A. millefolium, and S. grossularifolia) regardless of concentration and timing of 

application. This suggests that imazapic is not specific to cheatgrass, and that the use of imazapic 

could negatively impact native vegetation that are essential to the survival of sage grouse.

Although imazapic negatively impacted A. filipes, A. millefolium, and S. grossularifolia

performance, the response of A. filipes to imazapic applications was significantly less negative than 

that of the other species, indicating a need for additional studies to evaluate how plant functional 

types may mediate impacts of imazapic on their performance.

Figure 8a-c. Total standing biomass (shoots + roots) 

at harvest for a) Astragalus filipes, b) Achillea 

millefolium, and c) Sphaeralcea grossulariifolia

grown in soils that were burned or not burned at four 

different concentrations of imazapic. Significant 

differences among imazapic treatments are sown by 

different letters above the graphs (p < 0.05). Values 

are means + SE (n=10).
RESTORATION STRATEGIES

226

Figures 9a-b. Differences in the response to imazapic application among three forbs. A. f. (Astragalus 

filipes), A. m. (Achillea millefolium), S. g. (Sphaeralcea grossulariifolia). Different letters indicate 

significant differences in response to imazapic among forbs (p < 0.05). Values are means + SE (n=20).

Figures 10a-d. Differences in the total biomass of a) Astragalus filipes, b) Achillea millefolium, c) 

Sphaeralcea grossulariifolia, and d) Bromus tectorum in response to differences in the timing of 

imazapic application. Different letters indicate significant differences in response to imazapic 

application between control and imazapic treatments (p < 0.05). Values are means + SE (n=10).
RESTORATION STRATEGIES

227

Presentations

Pilliod, David S.; McIlroy, Suzan K.; Shinneman, Douglas J.; Arkle, Robert S.; Glenn, Nancy F.; 

Brabec, Martha M.; Germino, Matt J.; de Graaff, Marie-Anne. 2015. Effectiveness of managing 

cheatgrass and other fine fuels in non-native dominated sagebrush ecological sites. Restoring the 

West Conference; 28-29 October; Logan, UT.

Bringman, Billy; Johns, Aislinn; de Graaff, Marie-Anne. 2015. The impact of fuel reduction 

treatments on soil microbial processes and forb performance in a degraded semi-arid ecosystem. 

Great Basin Consortium Conference. 17-19 February; Boise, ID.

References

Baker, W. L.; Garner, J.; Lyon, P. 2009. Effect of imazapic on cheatgrass and native plants in 

Wyoming big sagebrush restoration for Gunnison sage-grouse. Natural Areas Journal 29: 204-209.

Brabec, M. M.; Germino, M. J.; Shinneman, D. J.; Pilliod, D. S.; McIlroy, S. K.; Arkle,

R. S. 2015. Challenges of establishing big sagebrush (Artemisia tridentata) in rangeland restoration: 

effects of herbicide, mowing, whole-community seeding, and sagebrush seed sources. Rangeland 

Ecology & Management 68: 432-435.

Busby, R. R. 2011. Cheatgrass (Bromus tectorum L.) interactions with arbuscular mycorrhizal fungi 

in the North American steppe: prevalence and diversity of associations, and divergence from native 

vegetation. Fort Collins, CO: Colorado State University. 127 p. Dissertation.

Chambers, J. C.; Wisdom, M. J. 2009. Priority research and management issues for the imperiled 

Great Basin of the western United States. Restoration Ecology 17: 707–714.

Chapin III, F. S.; Matson, P. A.; Mooney, H. A. 2002. Principles of terrestrial ecosystem ecology. 

New York, NY: Springer-Verlag. 447 p.

D’Antonio, C. M.; Vitousek, P. M. 1992. Biological invasion by exotic grasses, the grass/fire cycle, 

and global change. Annual Review of Ecology and Systematics 23: 63-87.

Forster, J. C., 1995. In: Alef, K.; Nannipiero, P., eds. Soil nitrogen methods in applied soil 

microbiology and biochemistry. San Diego, CA: Academic Press: 79–87.

Grymes, C.; Chandler, C. M.; Nester, P. R. 1995. Response of soybean (Glycine max) and rice 

(Oryza sativa) in rotation to AC 263,222. Weed Technology 9: 504-511.

Hart, S. C.; DeLuca, T. H.; Newman, G. S.; MacKenzie, M. D.; Boyle, S. I. 2005. Post- fire 

vegetative dynamics as drivers of microbial community structure and function in forest soils. Forest 

Ecology and Management 220: 166-184.

Huang, X.; Pan, J.; Liang, B; Sun, J.; Zhao, Y.; Li, S. 2009. Isolation, characterization of a strain 

capable of degrading imazethapyr and its use in degradation of the herbicide in soil. Current 

Microbiology 9: 363-367.
RESTORATION STRATEGIES

228

Kardol, P.; Wardle, D. A. 2010. How understanding aboveground-belowground linkages can assist 

restoration ecology. Trends in Ecology and Evolution 25: 670-679.

Knapp, P. A. 1996. Cheatgrass (Bromus tectorum L.) dominance in the Great Basin Desert: history, 

persistence, and influences to human activities. Global Environmental Change 6: 37-52.

Kyser, G. B.; DiTomaso, J. M.; Doran, M. P.; Orloff, S. B.; Wilson, R. G.; Lancaster, D. L.; Lile, D. 

F.; Porath, M. L. 2007. Control of medusahead (Taeniatherum caput-medusae) and other annual 

grasses with imazapic. Weed Technology 21: 66–75.

Prevey, J. S.; Germino, M. J.; Huntly, N. J.; Inouye, R. S. 2010. Exotic plants increase and native

plants decrease with loss of foundation species in sagebrush steppe. Plant Ecology 207: 39-51.

Pyke, D. A.; Wirth, T. A.; Beyers, J. L. 2013. Does seeding after wildfires in rangelands reduce 

erosion or invasive species? Restoration Ecology 21: 415-421.

Shinn, S. L.; Thill, D. C. 2002. The response of yellow starthistle (Centaurea solstitialis), annual 

grasses, and smooth brome (Bromus inermus) to imazapic and picloram. Weed Technology 16: 366–

370.

Shinn, S. L.; Thill, D. C. 2004. Tolerance of several perennial grasses to imazapic. Weed 

Technology 18: 60–65.

Tilman, D.; Knops, J.; Wedin, D.; Reich, P.; Ritchie, M.; Siemann, E. 1997. The influence of 

functional diversity and composition on ecosystem processes. Science 277: 1300-1302.

West, N. E., ed. 1983. Temperate deserts and semi-deserts. In: Ecosystems of the world. Vol. 5. 

Elsevier, Amsterdam: Elsevier Science. 522 p.

Wardle, D. A.; Bardgett, R. D.; Klironomos, J. N.; Setälä, H.; Van Der Putten, W. H.; Wall, D. H. 

2004. Ecological linkages between aboveground and belowground biota. Science 304: 1629-1633.

Whisenant S. 1990. Changing fire frequencies on Idaho’s Snake River plains: ecological and 

management implications. In: Proceedings from the symposium of cheatgrass invasion. Shrub die off 

and other aspects of shrub biology and management. General Technical Report INT -276. Ogden, 

UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment 

Station: 4-10.
RESTORATION STRATEGIES

229

Project Title Restoring Sagebrush After Large Wildfires: An Evaluation 

of Different Restoration Methods Across a Large Elevation 

Gradient

Project Agreement No. 15-IA-11221632-205

Principal Investigators and Contact Information 

Kirk W. Davies, Rangeland Scientist 

Agricultural Research Service

67826-A Hwy 205

Burns, OR 97720

541.573.4074, Fax 541.573.3042

kirk.davies@oregonstate.edu

Project Description

Introduction

We will evaluate sagebrush (Artemisia sp.) restoration success with five methods across an elevation 

gradient using a randomized block design. Treatments will be randomly assigned within block (site) 

and include: 1) natural recovery (control), 2) broadcast seeding sagebrush, 3) broadcast seeding 

sagebrush followed by roller-packing, 4) broadcast seeding sagebrush seed pillows, and 5) planting 

sagebrush seedlings. All sagebrush used in the study will be big sagebrush. However, Wyoming and 

mountain big sagebrush subspecies (A. tridentata var. wyomingensis, A. tridentata var. tridentata) 

will vary based on the potential natural community type. Wyoming and mountain big sagebrush will 

be seeded and planted on sites where they were dominant prior to burning, respectively. 

Treatments will be applied along five transects that span an elevation gradient from 1219 to 2134 m 

(4000 to 7000 ft.). Along each elevation gradient, treatments will be applied at approximately 1219, 

1372, 1524, 1676, 1829, 1981, and 2134 m (4000, 4500, 5000, 5500, 6000, 6500, and 7000 ft.) 

elevation. At each elevation and on each transect, treatments will be randomly assigned to five 5 x

10 m plots with a 2 m buffer between treatment plots in each year. Total number of blocks will be 35 

(5 elevation transects x 7 elevations per transect = 35 blocks) and total number of treatment plots 

will be 350 (5 treatments x 2 years x 35 blocks = 350 plots). All sagebrush seeding treatments will 

be applied at a rate of 1.1 kg pure live seed per hectare in the fall. Roller-packing will be applied by 

pulling a small roller-packer by hand across the plot after seeding. Seed pillows will be a mixture 

that promotes survival, growth, and establishment of sagebrush (exact formulation is not reported 

because of proprietary rights). Seeds and seed pillows will be broadcasted using a non-automated 

centrifugal flinger fertilizer spreader. Sagebrush seedlings will be hand planted at a density of 1 

seedling per m2. Sagebrush seedlings will be grown to a pre-planting height of approximately 15 cm 

by planting five sagebrush seeds in seedling cone containers in a greenhouse. Cone containers will 

be 3.8 cm diameter at the top and 21 cm tall. Sagebrush seedlings will be thinned to one individual 

per cone container. Sagebrush seedlings will be planted in the spring by digging a hole 

approximately 21 cm deep, placing the seedling in the hole, and pressing the soil around the roots of 

the seedlings. 
RESTORATION STRATEGIES

230

Objectives

The objectives of this study are to: 1) determine where different post-fire sagebrush restoration 

methods should be applied based on environmental characteristics to efficiently and effectively 

restore sagebrush, and 2) evaluate newly developed technologies to restore sagebrush steppe habitat. 

We hypothesize that: 1) natural recovery and seeding sagebrush will be more successful as elevation 

increases, 2) improving soil-seed contact by using a roller-packer after seeding sagebrush will 

improve seeding success, and 3) at lower elevations, seed pillows and planting seedlings will be 

more successful than other methods at establishing sagebrush.

Methods

Vegetation measurement will be conducted for four years after treatments are applied. Sagebrush and 

other shrub cover will be measured using the line-intercept method on three, 10 m transects within 

each plot. The 10 m transects will be placed at 1.5, 2.5, and 3.5 m points along the 5 m side of the 

treatment plot. Density of sagebrush and other shrubs will be measured by counting all plants rooted 

inside the 5 x 10 m plot. Average height of sagebrush will be determined by measuring the height of 

10 randomly selected sagebrush plants per plot. Sagebrush biomass production per plot will be 

estimated using height and two perpendicular diameter measurements of the sagebrush canopy from 

10 randomly selected sagebrush plants to determine average sagebrush production, and then 

multiplying average production by the density of sagebrush.

Herbaceous vegetation cover and density will be measured in 30, 0.2 m2 quadrats in each treatment 

plot. The quadrats will be spaced at 1 m intervals along each 10 m transect. Herbaceous cover will be 

visually estimated by species in the 0.2 m2 quadrats. Density will be measured by species by 

counting all plants rooted inside the 0.2 m2 quadrats.

Site characteristics will be measured at each block. Elevation, longitude, and latitude will be 

determined using topographical maps. Aspect will be determined using a compass. Slope will be 

measured with a clinometer. Soil depth will be determined by digging to a restrictive layer. Soil 

texture will be determined using the hydrometer method for the 0-20 cm depth and 20-40 cm depth. 

Precipitation will be determined from PRISM precipitation maps. Average, minimum, and maximum 

temperatures, Ecological Site, and frost free days will be determined for each block from Natural

Resources Conservation Service Soil Surveys. Post-fire weather characteristics will be determined 

from nearby weather stations.

Expected Results and Discussion

We expect to determine which methods are most successful at different elevations to restore 

sagebrush after wildfire. We also expect to determine how natural sagebrush recovery varies by 

elevation and other site characteristics. 
RESTORATION STRATEGIES

231

Project Title Forb Islands: Possible Techniques to Improve Forb Seedling 

Establishment for Diversifying Sagebrush-Steppe 

Communities

Project Agreement No. 15-IA-11221632-189

Principal Investigators and Contact Information

Douglas A. Johnson, Plant Physiologist

USDA-Agricultural Research Service

Forage and Range Research Lab 

Utah State University

Logan, UT 84322-6300

435.797.3067, Fax 435.797.3075

doug.johnson@ars.usda.gov

Thomas A. Monaco, Ecologist 

USDA-Agricultural Research Service

Forage and Range Research Lab 

Utah State University

Logan, UT 84322-6300

435.797.7231, Fax 435.797.3075

tom.monaco@ars.usda.gov

Other collaborators

Derek Tilley (NRCS), Scott Jensen (FS), Matt Madsen (BYU), Kris Hulvey (Utah State Univ.), 

Adam Fund (Utah State Univ.), Erica David (Perth, Australia), Jim Cane (ARS) 

Project Description 

Introduction

Public land management agencies (BLM, FS) are interested in expanding the biodiversity of 

rangeland plantings. Diverse native Great Basin forbs are essential for feeding both native pollinator 

communities (Cane 2008; Watrous and Cane 2011; Cane 2011; Cane et al. 2012, 2013) and wildlife, 

especially sage-grouse (Wisdom et al. 2002, Rowland et al. 2006). The seeding of native grasses and 

shrubs on Great Basin sage-steppe sites has been increasingly successful in recent years. Although 

many native forb species are becoming more commercially available because of Great Basin Native 

Plant Project (GBNPP) collaborations, establishment of native forbs remains sporadic and 

challenging. The period of favorable soil water and temperature conditions is often not long enough 

for successful forb establishment. A possible alternative to conventional seeding of forb species is to 

establish forb islands (distinct focal areas where forbs are established), which employ techniques to 

extend the favorable period for germination and establishment of Great Basin forbs. These forb 

islands could be sources of seed for the colonization of adjacent rangeland areas in subsequent years. 
RESTORATION STRATEGIES

232

Methods

The unique, patented Hollow Frame Fence System (HFFS) incorporates two parallel, specially 

designed snow fences that trap snow in uniform, dense drifts that slowly melt and extend soil water 

availability by 30-45 days (David 2013). The N-Sulate fabric is a medium-weight, permeable, UVtreated, and re-usable fabric designed to protect nursery ground beds, annual flowers, and vegetable 

gardens from freezing temperatures and rapid drying of the soil surface (Jensen 2009). Highly 

variable weather patterns in the Great Basin means that conditions needed to break dormancy and 

provide conditions conducive to forb establishment may not be present in most years. While seed 

dormancy may aid in preventing seed germination during unfavorable conditions, dormancy can 

limit the establishment of forbs in the face of invasive weed competition immediately after wildfires 

and allow weeds to preempt rangeland sites before forbs establish. New seed enhancement 

technology is being developed for breaking seed dormancy and enhancing seed germination and 

early seedling growth (Madsen and Hulet 2015). With this approach seeds can be coated with 

various treatments that can overcome seed dormancy impediments (Madsen and Svejcar 2011). 

Field studies were established during November 2015 with three primary treatments (HFFS, NSulate fabric, and control treatment) in a randomized complete block design with four replications at 

two sites in Utah (Spanish Fork, Clarkston) and one site in Idaho (Virginia). The two Utah sites are 

located on cultivated land, and the Virginia site was just placed into the Conservation Reserve 

Program (CRP) to control erosion and enhance pollinator and sage-grouse habitat. During 

November 2015, 33 rows of two forb species (basalt milkvetch and western prairie clover) treated 

with 15 specific seed coatings were seeded into 1.5-m long rows at a rate of 82 PLS m-2in each of 

the three treatments with a four-row Hege cone seeder. The remaining 1.5-m portion in each of the 

33 rows in each treatment combination was seeded to 10 forb species native to the Intermountain 

West with three seed treatments provided for each species in comparison with two check species, 

including small burnet (Sanguisorba minor) and sainfoin (Onobrychis viciifolia). 

Organza bags containing seed of each of the species with specific seed treatments were placed 

alongside the site treatments and covered with soil at each site for retrieval in January, April, and 

June of 2015 to determine seed treatment effects on germination. Seedling emergence, plant growth, 

and phenological development will be determined in of the seeded rows at each site on a regular 

basis during spring, summer, and fall of 2016 to determine best treatment combinations. Soil water 

content and soil temperatures will be monitored continuously at the three study sites to provide a 

mechanistic understanding of seedling responses and for hydrothermal model analysis (Hardegree et 

al. 2013). 

Figure 1. Plot configureation.
RESTORATION STRATEGIES

233

Anticipated Results

We anticipate that combinations of HFFS, N-Sulate fabric, and seed coating will create favorable 

winter and spring conditions that will warm the soil, retain spring surface moisture, and alleviate 

dormancy issues to enhance the establishment of forb species. If successful, these temporary mobile 

techniques could be used to create diverse forb islands across post-burn landscapes that will provide 

critical food for sage-grouse and native pollinators. 

References

Cane, J. H. 2008. Pollinating bees crucial to farming wildflower seed for U.S. habitat restoration. In: 

James, R. R.; Pitts-Singer, T. L., eds. Bees in agricultural ecosystems. New York: Oxford Univ. 

Press: 48-64.

Cane, J. H. 2011. Meeting wild bees’ needs on western US rangelands. Rangelands 33: 27-32.

Cane, J. H.; Love, B.; Swoboda, K. A. 2013. Breeding biology and bee guild of Douglas’ 

dustymaiden, Chaenactis douglasii (Asteraceae, Helenieae). Western North American Naturalist 72: 

563-568.

Cane, J. H.; Weber, M.; Miller, S. 2012. Breeding biologies, pollinators, and seed beetles of two 

prairie-clovers, Dalea ornata and Dalea searlsiae (Fabaceae: Amorpheae), from the Intermountain 

West, USA. Western North American Naturalist 72: 16-20.

David, E. 2013. Innovative snow harvesting technology increases vegetation establishment success 

in native sagebrush ecosystem restoration. Plant and Soil 373: 843-856.

Hardegree, S. P.; Moffet, C. A.; Flerchinger, G. N.; Cho, J.; Roundy, B. A.; Jones, T. A.; James, J. 

J.; Clark, P. E.; Pierson, F. B. 2013. Hydrothermal assessment of temporal variability in seedbed 

microclimate. Rangeland Ecology and Management 66: 127-135.

Jensen, S. 2009. The quest for natives: cultural practices, species screening and private growers. 

Ogden, UT: Department of Agriculture, Forest Service, Intermountain Research Station. Great Basin 

Native Plant Selection and Increase Project Annual Report: 12-18.

Madsen, M. D.; Hulet, A. 2015. Primed seed matrix composition and method of making extruded 

seed pellets. U.S. Patent Application No. 62/111,451.

Madsen, M. D.; Svejcar, T. J. 2011. Development and application of “seed pillow” technology for 

overcoming the limiting factors controlling rangeland reseeding success. U.S. Patent Application No. 

61/707,853.

Rowland, M. M.; Wisdom, M. J.; Suring, L. H.; Meinke, C. W. 2006. Greater sage-grouse as an 

umbrella species for sagebrush-associated vertebrates. Biological Conservation 129: 323-335.

Watrous, K. W.; Cane, J. H. 2011. Breeding biology of the threadstalk milkvetch, Astragalus filipes 

(Fabaceae), with a review of the genus. American Midland Naturalist 165: 225-240.
RESTORATION STRATEGIES

234

Wisdom, M. J.; Rowland, M. M.; Wales, B. C.; Hemstrom, M. A.; Hann, W. J.; Raphael, M. G.; 

Holthausen, R. S.; Gravenmier, R. A.; Rich, T. D. 2002. Modeled effects of sagebrush-steppe 

restoration on greater sage-grouse in the interior Columbia Basin, USA. Conservation Biology 16: 

1223-1231.

Additional Products

Management Applications

This project will provide land managers with information to diversify their rangeland revegetation 

projects. 
235

APENNDIX I – PLANT INDEX

A

Artemisia longiloba

Early sagebrush – 35

Achillia millefolium

Common yarrow - 13, 66, 76, 214, 217, 218, 

221, 222

Achnatherum hymenoides

Indian ricegrass - 3, 4, 22, 28, 68, 69, 108, 197

Achnatherum thurberianum

Thurber's needlegrass – 22, 76

Agoseris glauca 

Pale agoseris – 75, 76, 77

Agoseris grandiflora

Bigflower agoseris - 7, 38, 39, 40, 42, 44, 96

Agoseris heterophylla

Annual agoseris - 96

Agropyron cristatum

Crested wheatgrass - 12, 13, 205, 206, 207, 

208, 209, 210, 211, 212

Allium acuminatum

Tapertip onion - 22

Aremone munita

Flatbud pricklepoppy – 96

Arenaria macradenia ssp. ferrisea

Ferris' sandwort – 104

Artemisia nova

Black sagebrush – 69

Artemisia sp.

Sagebrush – 30, 225

Artemisia tridentata

Big sagebrush - 30, 31, 32, 33, 34, 35, 207, 

223, 225

Artemisia tridentata spp. tridentata

Basin big sagebrush - 32, 34, 35, 216, 225

Artemisia tridentata spp. wyomingensis

Wyoming big sagebrush - 9, 12, 32, 34, 35, 

66, 99, 100, 101, 102, 186, 189, 190, 191, 192, 207, 

209, 210, 211, 212, 215, 216, 223, 225

Artemisia tridentata ssp. vaseyana

Mountain big sagebrush - 32, 34, 66, 109, 225

Aster sp.

Aster – 104

Astragalus filipes

Basalt milkvetch - 5, 8, 11, 13, 54, 79, 104, 

145, 146, 147, 148, 149, 150, 171, 175, 214, 217, 

218, 220, 221, 222, 229

Astragalus utahensis

Utah Milkvetch - 100

Atriplex canescens

Fourwing saltbush – 76, 77

B

Balsamorhiza hookeri

Hooker's balsamroot – 76

Balsamorhiza saggittata

Arrowleaf Balsamroot– 76, 96, 97, 100

Blepharipappus scaber

Rough eyelashweed - 7, 38, 41, 42

Bouteloua gracilis 

Blue grama grass – 62, 63, 64

Bromus rubens

Red brome - 2, 65, 66, 67

Bromus tectorum

Cheat grass - 2, 4, 20, 65, 66, 67, 96, 97, 99, 101, 103, 

195, 197, 198, 199, 214, 215, 217, 218, 220, 221, 222, 223, 

224
PLANT INDEX

236

C

Chaenactis douglasii

Douglas' dustymaiden - 38, 42, 109, 156, 157, 

158, 159, 161, 162, 163, 165, 166, 167, 168, 229

Chrysothamnus nauseosus

Rubber Rabbitbrush - 76

Cleome lutea

Yellow beeplant - 11, 107, 151, 152, 

153, 154, 155, 171

Cleome serrulata

Rocky Mountain beeplant - 11, 96, 151, 152, 

153, 154, 155, 171

Cleome spp.

Bee plant - 11, 113, 151, 154

Collinsia parviflora

Blue eyed Mary - 7, 38, 40, 42

Crepis acuminate

Tapertip hawksbeard – 100, 104

Crepis intermedia

Limestone hawksbeard - 38, 41, 42, 156, 157, 

158, 159, 161, 162, 163

Cryptantha pterocarya

Wingnut cryptantha - 7, 38, 39, 42

Cryptantha sp.

Cryptantha – 104

Cymopterus bipinnatus

Hayden's cymopterus - 156, 157, 158, 161, 

162, 163, 171

Cymopterus nivalis

Snowline springparsley - 156

D

Dalea ornata

Western prairie clover - 5, 8, 11, 79, 104, 145, 

146, 147, 148, 149, 150, 171, 175, 229

Dalea searlsiae

Searls’ prairie clover - 8, 10, 79, 145, 146, 147, 

149, 150, 171, 175, 229

E

Enceliopsis nudicaulis

Nakedstem sunray - 104, 156, 159, 161, 162, 

163, 171

Erigeron pumilus

Navajo fleabane - 76

Eriogonum heracleoides

Parsnipflower buckwheat - 9, 10, 76, 77, 108, 

113, 114, 115, 116, 117, 118, 119, 171

Eriogonum ovalifolium

Cushion buckwheat - 9, 92, 93, 94, 95

Eriogonum umbellatum

Sulphur-flower buckwheat - 7, 9, 22, 45, 46, 

47, 49, 50, 51, 176, 77, 108, 113, 114, 115, 116, 

117, 118, 119, 171

Elymus elymoides

Squirreltail - 4, 65, 66, 197, 207

G

Gilia inconspicua

Shy gilia - 7, 38, 42

Grayia spinosa

Spiny hopsage - 76

H

Hedysarum boreale

Northern sweetvetch 'Timp' – 96, 100

Heliomeris multiflora

Showy goldeneye - 96, 104, 105, 156, 161, 

162, 163, 165, 166, 167, 168, 171

Heliomeris multiflora nevadensis

Nevada goldeneye – 96, 104

Hesperostipa comata

Needle and thread grass - 104

I

Ipomopsis aggregata

Skyrocket gilia - 104, 105, 156, 159, 162, 163, 

165, 166, 167, 168, 171
PLANT INDEX

237

K

Krascheninnikovia lanata

Winterfat - 12, 183, 184

Mentzelia albicaulis

Whitestem blazingstar - 7, 38, 42

Microsteris gracilis

L

Leymus cinereus

Basin wildrye - 6, 22, 24, 26, 27, 104, 105, 106, 

107

Ligusticum canbyi

Canby's licorice-root - 156, 158, 165, 166, 167, 

168

Ligusticum porteri

Porter's licorice-root - 156, 158, 165, 166, 168

Linum lewisii var. lewisii

Prairie flax – 104, 107

Linum perenne

Blue flax 'Appar' – 96, 100

Lomatium dissectum 

Fernleaf biscuitroot - 10, 76, 90, 120, 121, 122, 

124, 125, 126, 127, 128, 129, 130, 131, 132, 171

Lomatium grayi 

Gray’s biscuitroot - 10, 76, 120, 121, 122, 124, 

125, 126, 127, 128, 129, 131, 132, 171

Lomatium nudicaule

Barestem biscuitroot – 10, 96, 120, 121, 122, 

124, 125, 127, 128, 129, 131, 132, 171

Lomatium suksdorfii

Suksdorf’s desert parsley - 10, 120, 121, 122, 

124, 125, 127, 130, 132

Lomatium triternatum 

Nineleaf biscuitroot - 10, 110, 120, 121, 122, 

124, 125, 127, 128, 129, 131, 132, 171

Slender phlox - 7, 38, 42, 44

N

Nicotiana attenuata

Coyote tobacco - 77, 96, 156, 157, 158, 165, 

167, 168

O

Onobrychis viciifolia

Sainfoin – 228

P

Penstemon acuminatus 

Sharpleaf penstemon - 10, 133, 134, 135, 

137, 138, 139, 140, 141, 142, 143, 144, 171

Penstemon cyaneus

Blue Penstemon - 1, 10, 52, 53, 54, 55, 

107, 133, 134, 136, 137, 138, 139, 140, 142, 

143, 144, 171

Penstemon deustus

Scabland penstemon - 10, 133, 134, 135, 

137, 139, 140, 141, 142, 143, 144, 171

Penstemon eatonii

Firecracker penstemon - 100

Penstemon pachyphyllus

Thickleaf penstemon - 10, 96, 104, 105, 

133, 134, 136, 137, 138, 139, 140, 142, 144, 

171

Lotus utahensis

Utah trefoil - 3, 8, 88, 173, 174

Lupinus argenteus

Silvery lupine - 96, 100

M

Machaeranthera canescens

Hoary tansyaster - 9, 66, 108, 109, 110, 111, 

156, 157, 158, 160, 161, 162, 163, 165, 166, 167, 

168, 171

Penstemon palmeri

Palmer penstemon - 100

Penstemon speciosus 

Royal penstemon - 10, 76, 133, 134, 135, 136, 

137, 138, 139, 140, 142, 144, 164, 165, 166, 167, 

171

Phacelia hastata

Silverleaf phacelia - 7, 8, 38, 42, 76, 89, 90, 156, 158, 

159, 160, 161, 162, 163, 165, 167, 168, 171
PLANT INDEX

238

Phacelia linearis

Threadleaf phacelia - 156, 157, 158, 159, 160, 

161, 162, 163, 165, 166, 167, 168, 171

Phacelia crenulata var. corrugata

Cleftleaf wildheliotrope – 107

Poa fendleriana

Muttongrass - 96

Poa secunda

Sandberg bluegrass - 22, 27, 28, 66, 77, 216

Pseudoroegneria spicata

Bluebunch wheatgrass - 1, 6, 11, 12, 15, 16, 

17, 18, 19, 20, 21, 22, 28, 29, 30, 31, 33, 56, 57, 58, 

59, 76, 77, 178, 180, 181, 183, 184

Psoralidium sp.

Scurfpea - 108

Purshia tridentata

Bitterbrush – 108, 109

S

Sanguisorba minor

Small burnet - 228

Sisymbrium altissimum

Tumble-mustard – 216

Sphaeralcea grossulariifolia

Gooseberryleaf globemallow - 96, 107, 171, 

217, 221, 222

Sphaeralcea munroana

Munro globemallow - 100

T

Thelypodium milleflorum

Manyflower thelypody – 96, 156, 158, 160, 

161, 162, 165, 167, 168, 171

V

Vulpia octoflora

Sixweeks fescue - 65, 66