NRCS−Montana−Technical Note−Plant Materials−MT-99 1 

United States Department of Agriculture

NATURAL RESOURCES CONSERVATION SERVICE

Plant Materials Technical Note No. MT-99

August 2014

PLANT MATERIALS TECHNICAL NOTE

Seed Mixes for Acid and Heavy Metal Contaminated Sites in the Anaconda, Montana Area

Joe LeFebvre, Project Leader, 

Integration of Selected Native Plant Materials for Enhanced Restoration Activities in the UCFRB

Jim Jacobs, Plant Materials Specialist, USDA-NRCS, Bozeman, Montana

Four-row Cone Seeder

Introduction

The development of appropriate seed mixes for the re-vegetation of disturbed sites is a critical and 

challenging step in the restoration and reclamation process. Species and seed source selection, 

and their relative proportions in the mix, are particularly important. Practical issues such as 

availability and cost cannot be overlooked, although long-term success must be considered in any 

cost analysis. Numerous combinations of species and seeding rates may prove successful, and 

vary with factors such as soil texture, aspect, slope, project goals, degree of disturbance, method 

of seeding, cost, and other factors. Although this Technical Note presents potential seed mixes for 

re-vegetating or restoring native plant communities on smelter-impacted sites in the AnacondaButte area of Montana, the goal of the publication is to also provide the reader with the basic 

decision-making tools when developing custom mixtures.

Mix formulations for the smelter-impacted sites are based in part on seed mixes developed at the 

USDA-NRCS Plant Materials Center near Bridger, Montana, as well as the experience and testing 

of others. These mixes were successfully established on lime-amended, acid/heavy metal 

contaminated soils on Stucky Ridge near Anaconda, Montana. Results of those mixture-testing 

studies are presented herein. The establishment and survival of some of the species used in the 

experimental mixes were collected from Anaconda Superfund site and also tested in monoculture 

studies on Stucky Ridge. The results show they were able to tolerate the acid and heavy metal 

conditions of the soil there. The results are summarized in Montana Plant Materials Technical 

Note, MT-97, Acid and Heavy Metal Tolerant Plants for Restoring Plant Communities in the Upper 
NRCS−Montana−Technical Note−Plant Materials−MT-99 2 

Clark Fork River Basin (LeFebvre, 2014). That document should be used as a companion to this 

Technical Note when selecting appropriate species for developing seed mixes for this application. 

The recommended mixes and species contained herein do not constitute a comprehensive list of 

well-adapted materials, but are provided as examples.

I. Stucky Ridge Seed Mix Study

Plants able to survive in nutrient poor, acidic soil, contaminated with heavy metals such as copper, 

zinc, lead, cadmium, and arsenic, are thought to possess heritable genetic traits for tolerance to 

those conditions (Sainger et al., 2011). From this we assume the best plants for acid/heavy metal 

contaminated soils would be progeny from those found growing naturally at such sites. This was 

tested by comparing the establishment and persistence of seed mixtures composed of progeny 

from plant species found growing on the contaminated soils of Stucky Ridge with mixtures of 

commercially available seed of similar species. The hypothesis is; the progeny from Stucky Ridge 

seed will have greater establishment and persistence than the progeny from a commercial seed 

source when planted at Stucky Ridge. 

In May 2003 the Stucky Ridge test plot was established to test four different seed mixtures for 

survival and establishment success. Stucky Ridge is located in Deer Lodge County two miles 

northeast of Anaconda, Montana. Quaking aspen, Populus tremuloides; Woods' rose, Rosa 

woodsii; currant, Ribes spp.; rabbitbrush, Ericameria nauseosa; redtop, Agrostis gigantea; and 

basin wildrye, Leymus cinereus were sparsely growing on the site. The average annual 

precipitation at the site ranges from 10 to 13 inches with most of the precipitation occurring in late

spring to early summer. The average frost-free period is 90 to 105 days. The parent material is 

alluvium. The soil has a gravelly loam texture and is well drained. The slope at the plot site 

averages 5 to 10 percent. Prior to planting, 22 tons per acre of lime kiln dust was disked to a 6-inch

depth in November 2002. In the spring of 2003, commercial fertilizer (12% N, 16% P2O5, 30% K2O) 

was applied at a rate of 500 bulk pounds per acre and incorporated to 6 inches using a chisel plow.

Four seed mixtures were drill-seeded at 50 Pure Live Seeds (PLS) per linear row foot, at 14-inch 

row spacing in a randomized complete block design with four replications. Species for the seed 

mixes were chosen based on their predicted performance and potential ability to create a diverse 

plant community and formulated for two distinct applications. The “Upland” blends (see Tables 1 

and 2) were designed for sloping areas with acid/heavy metal soil and generally low water 

infiltration, in order to provide site stabilization and wildlife habitat. The “Waste Management Area”

(WMA) blends (see Tables 3 and 4) were designed to provide vegetative cover for areas with 

highly acidic soils and high heavy metal concentrations (native and non-native species).

“Developed” seed mixes were formulations composed of commercially available cultivars (native 

and non-native, see Tables 2 and 4). “Experimental” mixes attempted to utilize local, native

ecotypes of the same species used in the Developed mixes, when possible (see Tables 1 and 3). 

In a few cases, non-indigenous seed sources, and even one non-native (redtop) species, had to be 

utilized in the Experimental mix. Only three local, native seed source selections used in the WMA - 

Experimental mixes were available as cultivars or selections for the WMA - Developed mix. 

Seeding rates were based on Plant Materials Technical Note, MT-46 (Rev. 4), Seeding Rates for 

Conservation Species for Montana (Majerus et al., 2013).
NRCS−Montana−Technical Note−Plant Materials−MT-99 3 

I. Stucky Ridge Seed Mix Study (continued)

Table 1. Upland Areas – Experimental Seed Mix Formulation - Mix 1

Scientific Name Common Name

Accession

or

Variety

Origin

% Mix 

PLS by 

Weight

Full Stand 

Seeding 

Rate

PLS lb./acre

Grasses 

Achnatherum hymenoides Indian ricegrass 9081629 Deer Lodge Co., MT 15.0 5.0

Elymus trachycaulus slender wheatgrass Copperhead Deer Lodge Co., MT 15.0 7.0

Leymus cinereus basin wildrye Washoe Deer Lodge Co., MT 15.0 7.0

Pascopyrum smithii western wheatgrass 9081968 Deer Lodge Co., MT 5.0 10.0

Poa alpina alpine bluegrass 9016273 Gallatin Co., MT 10.0 13.0

Poa secunda (ampla) big bluegrass Opportunity Deer Lodge Co., MT 15.0 2.0

Pseudoroegneria spicata bluebunch wheatgrass 9081636 Deer Lodge Co., MT 15.0 7.0

Forbs

Symphyotrichum chilense Pacific aster 9078675 Deer Lodge Co., MT 2.5 2.0

Penstemon eriantherus fuzzytongue 

penstemon Old Works Deer Lodge Co., MT 5.0 3.0

Potentilla hippiana woolly cinquefoil 9076274 Silverbow Co., MT 2.5 NA

Table 2. Upland Areas – Developed Seed Mix Formulation - Mix 2

Scientific Name Common Name

Accession

or

Variety

Origin

% Mix 

PLS by

Weight

Full Stand 

Seeding 

Rate

PLS lb./acre

Grasses

Achnatherum hymenoides Indian ricegrass 'Nezpar' White Bird, ID 5.0 5.0

Elymus lanceolatus thickspike wheatgrass 'Critana' Hill County, MT 15.0 7.0

Elymus trachycaulus slender wheatgrass 'Revenue' SK, Canada 15.0 7.0

Festuca ovina sheep fescue 'Covar' central Turkey 10.0 2.0

Leymus cinereus basin wildrye 'Magnar' SK, Canada 15.0 7.0

Pascopyrum smithii western wheatgrass 'Rosana' Rosebud Co., MT 10.0 10.0

Poa secunda (ampla) big bluegrass 'Sherman' Sherman Co., OR 14.5 2.0

Pseudoroegneria spicata bluebunch wheatgrass 'Goldar' Asotin Co., WA 10.0 7.0

Forbs

Achillea millefolium western yarrow Great 

Northern Flathead Co., MT 2.5 0.5

Artemisia frigida fringed sagebrush 9082258 unknown 0.5 0.3

Linum lewisii Lewis flax 'Appar' Custer Co., SD 2.5 3.5
NRCS−Montana−Technical Note−Plant Materials−MT-99 4 

Table 3. Waste Management Areas - Experimental Seed Mix Formulation - Mix 3

Scientific Name Common Name

Accession

or

Variety

Origin

% Mix 

PLS by

Weight

Full Stand 

Seeding 

Rate

PLS lb./acre

Grasses 

Agrostis gigantea redtop 9076276 Deer Lodge Co., MT 15.0 0.5

Deschampsia cespitosa tufted hairgrass 9076290 Silverbow Co., MT 10.0 0.8

Elymus trachycaulus slender wheatgrass 9081620 Deer Lodge Co., MT 15.0 7.0

Leymus cinereus basin wildrye Washoe Deer Lodge Co., MT 15.0 7.0

Pascopyrum smithii western wheatgrass 9081968 Deer Lodge Co., MT 5.0 10.0

Poa secunda (ampla) big bluegrass 9081633 Deer Lodge Co., MT 10.0 10.0

Hesperostipa comata needle & thread grass 9078314 Deer Lodge Co., MT 10.0 9.0

Forbs

Symphyotrichum chilense Pacific aster 9078675 Deer Lodge Co., MT 10.0 2.0

Table 4. Waste Management Areas - Developed Seed Mix Formulation - Mix 4

Scientific Name Common Name

Accession

or

Variety

Origin

% Mix

PLS by

Weight

Full Stand 

Seeding 

Rate

PLS lb./acre

Grasses 

Thinopyrum intermedium intermediate 

wheatgrass 'Greenar' Former USSR 10.0 10.0

Bromus inermis smooth brome 'Manchar' Manchuria, China 15.0 8.0

Elymus lanceolatus thickspike wheatgrass 'Critana' Hill County, MT 10.0 7.0

Elymus trachycaulus slender wheatgrass 'Revenue' SK, Canada 15.0 7.0

Leymus cinereus basin wildrye 'Magnar' SK, Canada 15.0 7.0

Poa secunda (ampla) big bluegrass 'Sherman' Sherman Co., OR 10.0 2.0

Nassella viridula green needlegrass 9082255 Washington 10.0 6.0

Forbs

Medicago sativa alfalfa 'Ladak' Kashmir, India 15.0 5.0

II. Stucky Ridge Seed Mixture Evaluations

Establishment and survival were measured by counting seeded plant density from 10.76 ft2 sample 

frames in June and August of 2003, by estimating the percent foliar cover of the seeded species, 

the relative vigor of species on a scale of 1 to 9, the height of the tallest plant, and biomass of 

seeded species clipped from a one square meter sample frame in each treatment plot in year 

2004, 2005, 2006, and 2007 (see Addendum 1). Density data were analyzed using a split-plot in 

time analysis of variance model with density as the dependent variable, mixture as the whole-plot 

independent variable, and sample date as the sub-plot independent variable. Cover, vigor, height 

and biomass data were dependent variables in a split-plot in time analysis of variance model with 

mix as the whole-plot independent variable and year as the sub-plot independent variable.
NRCS−Montana−Technical Note−Plant Materials−MT-99 5 

III. Stucky Ridge Seed Mixture Trial Results

Table 5. Mean densities (plants per square foot) of mixes at two sampling dates during the 

establishment year at Stucky Ridge. A split plot in time analysis of variance model found no 

significant differences among seed mixtures or sampling dates (p>0.1).

Date Upland Exp. Upland Dev WMA Exp. WMA Dev

24 June 2003 10.3 14.9 10.0 16.8

26 August 2003 11.9 11.2 11.1 17.4

Seeded plant densities during the establishment year, 2003, are listed in Table 5. The analysis 

found no significant differences among mixes or between sampling dates (p>0.1) suggesting the 

experimental and development mixes established equally well at both sites and establishing plants 

survived the first year.

Table 6. Mean percentage foliar cover. When comparing means for statistical differences among 

columns and rows, different letters following the means indicate differences (Tukey HSD 

comparison test α=0.05).

Year Upland Exp. Upland Dev. WMA Exp. WMA Dev.

2004 61 AB 26 B 60 AB 28 B

2005 50 AB 36 AB 65 A 38 AB

2006 28 B 27 B 34 AB 26 B

2007 51 AB 43 AB 56 AB 65 A

The effect of the seed mixture treatment on plant foliar cover depended on the year sampled 

(P=0.0207). This interaction is mainly the result of the WMA Developed mix which had low cover in 

2004 and 2006 (28% and 26%, respectively) and increased significantly to 65% in 2007 suggesting 

the cover resulting from this mix increased over time (see Table 6). However, there were no 

differences in cover among mixes in any year. The WMA Experimental mix had higher cover (65%) 

in 2005 than the other mixes in 2006, and the Upland Developed mix in 2004. Its cover was not 

significantly different than the cover resulting from other mixes in 2005 or its cover in other years 

(see Table 6). Averaged over all mixtures, cover was lower (p<0.0001) in 2006 (29%) than in 2004 

(44%), 2005 (47%) and 2007 (54%). Averaged over all years, the WMA Experimental mix (54%) 

had greater cover (p=0.0366) than the Upland Developed mix (33%) but not the Upland 

Experimental mix (47%) or the WMA Experimental mix (40%).

Table 7. Mean vigor rating. A vigor rating of 1 is the highest rating and a vigor rating of 9 is the 

lowest rating. When comparing means for statistical differences among columns and rows, different 

letters following the means indicate differences (Tukey HSD comparison test α=0.05).

Year Upland Exp. Upland Dev. WMA Exp. WMA Dev.

2004 2.6 CD 4.3 ABCD 2.3 D 4.1 ABCD

2005 4.2 ABCD 4.4 ABC 3.8 ABCD 4.1 ABCD

2006 5.1 AB 4.4 ABC 5.3 AB 5.3 A

2007 3.6 ABCD 4.2 ABCD 3.3 BCD 3.4 ABCD
NRCS−Montana−Technical Note−Plant Materials−MT-99 6 

The effect of seed mixture treatment on plant vigor depended on the year sampled (p=0.0311). 

This is the result of the Experimental mixes having different ratings over time on both the Upland 

and WMA sites. In the Upland Experimental mix plots, plant vigor declined from a rating of 2.6 in 

2004 to 5.1 in 2006, but vigor in both those years were not rated differently than the vigor in 2005 

or 2007 (see Table 7). In the WMA Experimental mix plots, plant vigor declined from 2.3 in 2004 to 

5.3 in 2006, but was not different than vigor in 2005 or 2007 (see Table 7). Estimated plant vigor 

did not differ statistically among seed mixes in each year. Averaged over all years, the WMA 

Experimental mix (3.6) had greater (p=0.0366) vigor than the Upland Developed mix (4.3) but not 

the Upland Experimental mix (3.9) or the WMA Developed mix (4.2). Averaged over all mixtures, 

vigor ratings were highest (p<0.0001) in 2004 (3.3), followed by 2007 (3.6) and 2005 (4.1) and 

lowest in 2006 (5.0).

Table 8. Mean plant height in inches. There is no seed mix by year interaction (p>0.1) thus no 

statistical comparisons are presented on the table.

Mean plant heights of the tallest plant by mixture and year are presented in Table 8. The mixture 

treatment did not interact with year (p=0.1169), nor did heights averaged over the four mixtures 

change over the four years of sampling (p>0.1). However, the tallest plant height was affected by 

the mixture seeded (p=0.0022). Averaged over all years, the tallest plants in the Upland 

Experimental seed mix plots reached 28.9 inches tall and were taller than the tallest plants in the 

Upland Developed mix which were 22.7 inches tall. The tallest plants in the WMA Experimental mix 

were 29.6 inches tall, they were also taller than the tallest plants in the Upland Developed mix, but 

were not significantly taller than the tallest plants in the WMA Developed mix (26.8 inches).

Table 9. Mean plant biomass (pounds/acre). When comparing means for statistical differences 

among columns and rows, different letters following the means indicate (Tukey HSD comparison 

test α=0.05).

Year Upland Exp. Upland Dev. WMA Exp. WMA Dev.

2004 5,303.5 AB 1,795.8 BC 7,978.1 A 4,013.1 ABC

2005 1,220.7 C 1,592.2 BC 3,666.7 BC 2,956.7 BC

2006 968.0 C 1,503.8 BC 1,582.4 BC 1,240.4 BC

2007 1,195.7 C 1,469.0 BC 1,811.0 BC 1,746.7 BC

The effect of seed mixture on biomass produced was dependent on the year sampled (p=0.0177). 

In 2004, the WMA Experimental mix had greater biomass than the Upland Developed mix (see 

Table 9). Mixtures did not differ in biomass in other years. Biomass in the Experimental mix on the 

Upland site declined from 2004 to 2005, 2006 and 2007 (see Table 9). The Experimental mix on 

the WMA site declined from 2004 to subsequent years also (see Table 9). Averaged over all years, 

the biomass sampled from the WMA Experimental mix plots (3,759.5 pounds/acre) was greater 

(p=0.0135) than biomass sampled from the Upland Developed mix plots (1,590.4 pounds/acre), but 

neither of these biomasses were different than biomass sampled from the Upland Experimental

(2,171.8 pounds/acre) or WMA Developed mix plots (2,489.2 pounds/acre). Averaged over all 

mixtures, biomass declined (p<0.0001) from 2004 (4,772.2 pounds/acre) to 2005 (2,359.3

pounds/acre), 2006 (1,323.4 pounds/acre), and 2007 (1,555.6 pounds/acre).

Year Upland Exp. Upland Dev. WMA Exp. WMA Dev.

2004 31.1 18.5 32.7 22.5

2005 29.6 22.9 29.9 28.4

2006 26.8 28.0 26.4 26.8

2007 28.4 21.7 29.2 28.8
NRCS−Montana−Technical Note−Plant Materials−MT-99 7 

Biomass may have been strongly influenced by one or two species in each mix. The Experimental 

mixes were dominated by Copperhead slender wheatgrass, while the Developed mixes were 

dominated by 'Revenue' slender wheatgrass and 'Critana' thickspike wheatgrass.

The analysis of the Stucky Ridge study provides little support for the assumption that progeny of 

locally collected plants establish and survive better on the remediated site conditions than progeny 

of plants developed through standard plant materials selection and testing for cultivar 

development. Initial establishment densities in 2003 did not differ between the Experimental and 

Developed mixes at either the Upland or WMA sites (see Table 5). Cover, vigor, height, and 

biomass in subsequent years also did not differ between mixtures when compared by site or year 

(see Tables 6, 7, 8 and 9). It is possible soil remediation may have reduced any advantage locally 

collected plant materials may have had in establishment and survival. Additionally, plants 

developed through the testing and selection process of cultivar development may be adapted to a 

wide range of soil conditions including acid and heavy metal soil extremes. 

The greater biomass production of the WMA Experimental mix on the WMA site compared to the 

WMA Developed mix (see Table 9) provides some support for the local adaptation assumption, but 

these mixtures where designed for, and applied to different site conditions and therefore is not a 

good comparison. Cover, vigor, and biomass results (WMA Experimental mix was greater than 

Upland Developed mix) when averaged over all years provides similar support. The height results 

when averaged over all years provides the strongest support for the assumption under the Upland 

site conditions where plants in the Upland Experimental plots were taller than plants in the Upland 

Developed mix.

The remainder of this technical note is a step-by-step guide dedicated to explaining the seed mix 

development process in a manner that allows custom design of seed mixes. 

IV. Seed Mix Design Process

A. Species Selection

Species selection is often the biggest challenge when developing a seeding mix. For this project, 

mixtures were constructed of species and rates based on NRCS Plant Materials Program protocols 

for establishing various vegetative conservation practices (Majerus et al., 2013, NRCS 2013). 

Species selected for the mixes tested on Stucky Ridge were chosen based on the species proven 

or anticipated functional performance in a plant community and compatibility with other species in 

the mix. A typical herbaceous conservation mix often includes one grass species known for rapid 

establishment, one rhizomatous grass species for site stabilization, other grasses for diversity and 

as structural components, one or more wildflowers (forbs) for diversity and as a source of pollinator 

and beneficial insect habitat, and one or more woody plants for vertical strata and wildlife habitat.

Recommended mixes may vary if the restoration site is high versus low elevation, northerly versus 

southerly exposure, or if soils or climatic conditions vary widely over the target site. Mixes also vary 

with the intended purpose of the conservation planting, the method of seeding, and the severity of 

the site disturbance.

The success of re-establishment of a vegetative community on a severely disturbed site is 

dependent on many factors. Seeding a disturbed site with a mix of seeds from several different 

species is valuable for the following reasons:

1. Ecosystem stability depends in part on the degree of diversity among plants inhabiting the 

area. There is a direct relationship between ecosystem stability and plant diversity. More diverse 

communities establish faster, require fewer nutrients, provide better soil cover, and grow more 

vigorously. More diverse communities are also better able to resist weed invasion, prevent erosion 

and tolerate drought and disease, resulting in lower maintenance requirements for that site. 
NRCS−Montana−Technical Note−Plant Materials−MT-99 8 

A. Species Selection (continued)

Sowing a mix of seeds increases the plant diversity and, therefore, can result in an increase the 

stability of the ecosystem. 

2. When erosion control is a primary goal of the re-seeding, a rapidly establishing species is an 

important component of the seed mix. Such species typically establish quickly the first year and 

then fade over time. Their function in mixes includes rapid soil stabilization, shade, wind protection, 

and moisture and nutrient retention until slower growing native species can establish and mature. 

Species such as slender wheatgrass, Elymus trachycaulus and cereal grains (for temporary cover) 

are rapid establishing.

3. In severely impacted areas, such as land in close proximity to the Anaconda smelter, species 

or selections with demonstrated tolerance to acid and heavy metal laden soils, and capable of reseeding, are necessary in the seed mix. As previously noted, a description of these species 

appears in Montana Plant Materials Technical Note, MT-97, Acid and Heavy Metal Tolerant Plants 

for Restoring Plant Communities in the Upper Clark Fork River Basin. 

4. Species that are drought tolerant, winter hardy, heavy root producers, and/or have excellent 

seedling vigor (such as thickspike wheatgrass, Elymus lanceolatus) are well suited for seed mixes 

on severely impacted mined sites. Re-establishing a vegetative cover on severely disrupted sites 

requires plant species capable of tolerating numerous severe growing conditions.

5. The ability to withstand grazing or browsing pressures from cattle or wildlife is important to the 

long-term productivity of the reclaimed site. Palatable species capable of recovering well following 

animal utilization (such as western wheatgrass, Pascopyrum smithii) should be a part of the seed 

mix.

6. Species providing cover for wildlife are important. The interactions between wildlife and the 

plant communities they live in are important to the stability of the area. Including species that are 

important food sources for pollinators and other wildlife ensures species diversity, and therefore 

improves the likelihood of restoration success. Seed mixes should include tall stature species 

providing wildlife cover (such as basin wildrye, Leymus cinereus), as well as food and habitat for 

pollinators (such as silverleaf phacelia, Phacelia hastata). Reference Addendum 2, "Important 

Characteristics of Plants in A Mine Reclamation Seed Mix", for a summary of the characteristics 

exhibited by the plants in the tested seed mixes.

Potential species for inclusion in mixes are often generated from NRCS soils surveys, Ecological 

Site Descriptions, local botanical surveys, and other sources. Use Montana Plant Materials 

Technical Note, MT-97, Acid and Heavy Metal Tolerant Plants for Restoring Plant Communities in 

the Upper Clark Fork River Basin (LeFebvre, 2014) for descriptions of well-adapted species and 

selections.

Additional considerations when developing a seed mix include commercial availability and cost, 

problems incurred when combining highly competitive and non-competitive species, and species 

compatibility. Seed cost is an important consideration on large-scale reclamation projects and, in 

some cases; it may be possible to substitute less expensive species. That said, management 

objectives, species function, and long-term success should always be the determining factors in 

species selection. Aggressive species may dominate and crowd out other species in a mix and 

should be used sparingly or replaced with a similar functioning, but less aggressive option. In 

addition to competitiveness, other plant attributes such as seed size and shape, speed of seedling 

emergence, plant stature, tolerance to site conditions such as soil pH or salinity, may also affect 

compatibility and should be considered.
NRCS−Montana−Technical Note−Plant Materials−MT-99 9 

B. Seeding Rates

All suggested seeding rates should be calculated on a Pure Live Seed (PLS) basis. The value 

takes into account seed lot impurities such as inert material, other crops seeds, weed seeds, and 

the germination (viability) of the lot. The result is a calculation based on actual live seeds put in the 

ground. Seeding rates, the amount of live seed planted per unit area, are based on Montana Plant 

Materials Technical Note, MT-46 (Rev. 4), Seeding Rates for Conservation Species for Montana, 

(Majerus et al., 2013), which recommends the number of PLS pounds of seed to plant per acre in 

order to obtain a full (solid or single species) stand of that species when sown with a drill planter. 

Individual species seeding rates are therefore adjusted downward in seeding mixtures, since 

seldom is one species used to create a solid stand. Rates of seeding of each species are based on 

their relative percentage in the mix.

Table 10 illustrates seeding rate calculations when drill seeding a mix on a good site with 12-inch 

row spacing. The species listed in the table are provided primarily for demonstration purposes. The 

table and procedures described may be used to calculate the seeding rates for other appropriate 

species, as long as the columns in the tables are adjusted for the recommended percentage of 

each species in the mix, and the drilled full stand seeding rate in PLS pounds per acre for each 

species is selected. Reference the Montana Plant Materials Technical Note, MT-46 (Rev. 4), 

Seeding Rates for Conservation Species for Montana (Majerus et al., 2013) for that information.

The following explanations describe how to calculate the values in each of the columns in Table 10

below. Follow along on the table with the explanation for each column. A more detailed explanation 

of planting practices to improve seeding success can be found in the Montana Plant Materials 

Technical Note, MT-46 (Rev. 4), Seeding Rates for Conservation Species for Montana (Majerus et 

al., 2013). 

Table 10. Seeding Rates for Conservation Plant Species When Drill Seeding A Mix on A Good Site.

1 

Species

2 

Preferred

Selection

3 

Alternative

Selection

4 

Function

5 

Recommended

Percentage

in Mix

(decimal)

6 

PLS 

Seeds

per

Pound

PLS/lb.

7 

Drilled 

Full 

Stand

Seeding

Rate

PLS 

lb./acre

8 

Drilled 

Mix

Good 

Site

Seeding

Rate

PLS 

lb./acre

9 

Mix

Resultant

PLS 

Seeds

Per 

Square 

Foot

PLS/ft2

slender 

wheatgrass Copperhead Pryor rapid 

establishment 0.2 140,000 7.0 1.4 4.5

Nevada 

Sandberg 

bluegrass

Opportunity local 

ecotypes

cover, 

longevity 0.2 1,029,000 2.0 0.4 9.4

basin 

wildrye Washoe Trailhead vertical height, cover 0.2 144,000 7.0 1.4 4.6

Indian 

ricegrass Rimrock local ecotypes

diversity, 

wildlife food 0.1 235,000 5.0 0.5 2.7

fuzzytongue 

penstemon

Old Works local 

ecotypes

diversity, 

pollinator 0.1 358,000 3.0 0.3 2.5

yarrow

Great 

Northern

local 

ecotypes

diversity, 

pollinator 0.1 2,850,000 0.5 0.05 3.3

winterfat Open Range local 

ecotypes winter forage 0.1 93,000 3.0 0.3 0.6

Totals: 1.0 NA NA 4.4 27.6
NRCS−Montana−Technical Note−Plant Materials−MT-99 10

B. Seeding Rates (continued)

Species listed in column 1 should be chosen based on their proven ability to work well in the 

intended conservation practice in Montana and Wyoming. Seed of each species must be 

commercially available, cost-effective, and able to be direct seeded. Certified seed is always 

recommended and preferred (Scianna et al., 2011). 

The Preferred Selection (see column 2) is usually a selection that has been tested in the local 

ecosystem or environment and has proven to establish well under those specific conditions. 

Preferred selection status is often based on choosing seed sources whose origin was in the closest 

proximity to the intended planting site.

The Alternative Selection (see column 3) usually consists of selections made from parent plants 

found growing outside the local area, but have proven to establish and grow well under the 

intended conditions and environment. 

For more information on appropriate selections and seed sources, see Montana Plant Materials 

Technical Note, MT-67, Seed Source Selection, Use of Certified Seed, and Appropriate Seed 

Release Class Improve Conservation Planting Success (Scianna et al., 2011), and Montana Plant 

Materials Technical Note, MT-69, Standard and Preferred Forage and Reclamation Plants for Use 

in Montana and Wyoming (Hybner et al., 2011).

Column 4 indicates the function each species performs when it is included in a seed mix. As 

explained previously, the best seed mix will have a combination of species that together will 

perform most of the functions described in the table.

The next step is to determine the percentage of each species to use in the mixture (see column 5). 

This decision is based on several factors, including species function, competitiveness, speed of 

establishment, as well as the experience and expertise of the restorationist.

The only time the mix would consist of 100% of an individual species would be if a pure stand of a 

single species was desired. The recommended planting rate of each species should reflect its

specific percentage in the total mixture. Other plants within the mix will make up the remaining 

percentage of the mixture (100% total). The final percentage used for each species is based on the 

conservation objective of the planting (e.g., wildlife versus erosion control). Adjust the percentage 

used for each species, with the greatest percentage of the mix consisting of the species that best 

meet your management objective.

The values in column 6 have been calculated from the average of numerous seed lots of the 

species and its selections, and are provided in Plant Materials Technical Note MT-46 (Rev.4), 

Seeding Rates for Conservation Species for Montana (Majerus et al., 2013).

The number of Pure Live Seed (PLS) pounds per acre (see column 7) recommended for each 

species are based on planting a desired number of target seeds per linear foot or square foot, 

depending on whether the seed is drilled in rows (linear) or broadcast (area). The standard rule of 

thumb is to sow 20 to 30 PLS seeds per linear or square foot for most plantings; although this

number varies with seed size (number of seeds per pound), seedling vigor, type of seeding 

equipment, and conservation practice. It is important to note the recommended number of PLS 

pounds per acre for a full drill seeding are based on 12-inch row spacing, and must be adjusted 

when the row spacing is greater than 12 inches. The target-seeding rate per foot (based primarily 

on seed size) is listed in Table 11. Small seeds are seeded at higher rates because they generally 

have less carbohydrate reserves and perish more easily than large seeds, and have a greater 

potential to be planted too deep. Large-seeded plants often produce larger, more competitive 

seedlings that tend to survive well. The seeds from large-stature plants can be difficult to sow in 

high numbers because of their large size.
NRCS−Montana−Technical Note−Plant Materials−MT-99 11

B. Seeding Rates (continued)

Table 11. Target Number of Seeds per Foot Based on Seed Size

Seed Size Class

Number of PLS

per Pound

Target Number of PLS 

per Foot

small >800,000 30 to 50

medium 80,000 to 800,000 20 to 25

large <80,000 15 to 20

The values in column 8 (see Table 10) were simply calculated by multiplying the Drilled Full Stand 

Seeding Rate PLS value (see column 7) times the Recommended Percentage in Mix value (see 

column 5). This value represents how many PLS pounds per acre of each species are needed for 

the seeding mixture when using a drill and planting on a “good” site. Unfortunately, most sites in 

the Butte-Anaconda area do not qualify as “good”. Column 9 lists how many seeds of each species 

will be sown per square foot at the recommended rate and percentages specified in the mix. It is 

calculated by multiplying the number of PLS seeds per pound value (see column 6) times the 

Drilled Good Site Mix Seeding Rate PLS value (see column 8), and then dividing the product by 

43,560 (the number of square feet in an acre).

The recommended seeding rate also varies with the planting method. The seeding rate when

broadcasting is twice the drilled seeding rate. The seeding rate can also vary with the type of 

conservation practice. For broadcast or hydro-seeded Critical Area Plantings, the seeding rate is 

up to twice the recommended rate for broadcast seeding on a good site, and up to 4 times the rate 

of drill seeding on a good site.
NRCS−Montana−Technical Note−Plant Materials−MT-99 12

B. Seeding Rates (continued)

Table 12 demonstrates seeding rate calculations when drill seeding a mix in a critical area, 

whereas Table 13 demonstrates seeding rate calculations when broadcast seeding a mix in a 

critical area. In Table 12, to calculate the seeding rate for a drill planted, critical area (see column 

8), multiply the Recommended Percentage in Mix value (see column 5) times the Drilled Full Stand 

Seeding Rate PLS value (see column 7), and then multiply the product by 2. 

Table 12. Seeding Rates for Conservation Plant Species When Drill Seeding A Mix in A Critical Area

1 

Species

2 

Preferred

Selection

3 

Alternative

Selection

4 

Function

5 

Recommended

Percentage

in Mix

(decimal)

6 

PLS 

Seeds

per

Pound

PLS/lb.

7 

Drilled 

Full 

Stand

Seeding

Rate

PLS 

lb./acre

8 

Drilled

Critical 

Area

Mix

Seeding

Rate

PLS 

lb./acre

9 

Mix

Resultant

PLS 

Seeds

Per 

Square 

Foot

PLS/ft2

slender 

wheatgrass Copperhead Pryor rapid establishment 0.2 140,000 7.0 2.8 9.0

Nevada 

Sandberg 

bluegrass

Opportunity other local 

ecotypes

cover, 

longevity 0.2 1,029,000 2.0 0.8 18.9

basin 

wildrye Washoe Trailhead vertical height, cover 0.2 144,000 7.0 2.8 9.3

Indian 

ricegrass Rimrock local ecotypes

diversity, 

wildlife food 0.1 235,000 5.0 1.0 5.4

fuzzytongue 

penstemon

Old Works other local 

ecotypes

diversity, 

pollinator 0.1 358,000 3.0 0.6 4.9

yarrow

Great 

Northern

local 

ecotypes

diversity, 

pollinator 0.1 2,850,000 0.5 0.1 6.5

winterfat Open Range local 

ecotypes winter forage 0.1 93,000 3.0 0.6 1.3

Totals: 1 NA NA 8.7 55.3
NRCS−Montana−Technical Note−Plant Materials−MT-99 13

B. Seeding Rates (continued)

To calculate the seeding rate (see Table 13) for a broadcast planted, critical area (see column 8), 

multiply the Recommended Percentage in Mix value (see column 5) times the Drilled Full Stand 

Seeding Rate PLS value (see column 7), and then multiplying the product by 4.

Table 13. Seeding Rates for Conservation Plant Species When Broadcast Seeding a Mix in a Critical 

Area

1 

Species

2 

Preferred

Selection

3 

Alternative

Selection

4 

Function

5 

Recommended

Percentage

in Mix

(decimal)

6 

PLS 

Seeds

per

Pound

PLS/lb.

7 

Drilled 

Full 

Stand

Seeding

Rate

PLS 

lb./acre

8 

Broadcast 

Critical 

Area

Mix

Seeding

Rate

PLS

lb./acre

9 

Mix

Resultant

PLS 

Seeds

Per 

Square 

Foot

PLS/ft2

slender 

wheatgrass Copperhead Pryor rapid establishment 0.2 140,000 7.0 5.6 18.0

Sandberg 

bluegrass Opportunity other local ecotypes

cover, 

longevity 0.2 1,029,000 2.0 1.6 37.8

basin 

wildrye Washoe Trailhead vertical height, cover 0.2 144,000 7.0 5.6 18.5

Indian 

ricegrass Rimrock local ecotypes

diversity, 

wildlife food 0.1 235,000 5.0 2.0 10.8

fuzzytongue 

penstemon

Old Works other local 

ecotypes

diversity, 

pollinator 0.1 358,000 3.0 1.2 9.9

yarrow

Great 

Northern

local 

ecotypes

diversity, 

pollinator 0.1 2,850,000 0.5 0.2 13.1

winterfat Open Range local 

ecotypes winter forage 0.1 93,000 3.0 1.2 2.6

Totals: 1 NA NA 17.4 110.7

Summary

Other seed mixes have been developed for reclamation of the Anaconda Superfund Site. Richard 

Prodgers, Bighorn Environmental Sciences, developed eight seed mixes for the Natural Resources 

Damage Program, and Warren Keammerer, Ecological Consultants, Inc., developed a seed mix for 

ARCO. The mixes were very similar in their basic species composition to each other and to the 

Bridger Plant Materials Center mixes.

Each of the seed mixes was evaluated on whether it contained the essential components of a good 

seed mix. The essential components of a seed mix, as discussed earlier, include rapid rate of 

establishment, longevity, at least one rhizomatous grass, drought tolerance, acid tolerance, and 

provides food and cover for wildlife, including pollinators.

The component missing most often from the NRDP and ARCO mixes was the inclusion of a forb or 

shrub species to serve as a food source for pollinators. The mixes also differed in the rate at which 

the seed was applied, the percentage composition of each of the species in the mix, and the 

percentage composition of seed originating from local sources.

The mixes developed by the Bridger Plant Materials Center differed from the mixes developed by 

the others by including species grown from seed that originated at the Anaconda Superfund site.
NRCS−Montana−Technical Note−Plant Materials−MT-99 14

References

Atlantic Richfield Company, 2006. Anaconda Smelter NPL Site, Anaconda Regional Water, Waste 

and Soils Operable Unit. Data Summary and Analysis Report for RDU 3 - Smelter Hill Uplands, 

Aspen Hills Area. September 2006. Available at: Summary of reclamation activities in the 

Anaconda Superfund site.

Hybner, Roger G., Graham, Elizabeth C., Majerus, Mark E., Majerus, Shannon G. 2009. 

Comparative Evaluation of Grasses, Forbs, And Seed Mixtures from “Local” Versus “Non-Local” 

Origins at (Stucky Ridge) Anaconda, Mt. Available at: The results of a study comparing local and 

nonlocal plants growing on Stucky Ridge.

Hybner, R., Scianna, J., Ogle, D., St. John, L., Tober, D., Duckwitz, W., Parr, S., Clause, K. USDANRCS. July 2011. Plant Materials Technical Note, MT-69. Standard and Preferred Forage and 

Reclamation Plants for Use in Montana and Wyoming. Available at: Attributes of grass/forb species 

for reclamation.

Jain, S.K.; Bradshaw, A.D. 1966. Evolutionary divergence among adjacent plant populations. 

Heredity, 21: 407-441.

LeFebvre, J. 2014. Plant Materials Technical Note No. MT-97. Acid and Heavy Metal Tolerant 

Plants for Restoring Plant Communities in the Upper Clark Fork River Basin. Available at: Plants 

established on acid/heavy metal sites.

Majerus, M.E. 2003. New Native Pre-Varietal Germplasm Releases for the Northern Great Plains 

and Intermountain Region. Available at: New native releases in the Northern Great Plains, and 

Intermountain Regions.

Majerus, M., Scianna, J., Jacobs, J. USDA-NRCS. September 2013. Plant Materials Technical 

Note No. MT-46 (Rev. 4). Seeding Rates for Conservation Species for Montana. Available at: How 

to determine the amount of seed needed for a conservation planting.

Montana Department of Justice Natural Resource Damage Program. December 2007. Draft 

Conceptual Smelter Hill Area Uplands Resources Restoration Plan. Available at: NRDP draft 

restoration plan for the Anaconda Superfund Site.

NRCS. 2013. Natural Resources Conservation Service, Natural Conservation Practice Standard 

Critical Area Planting, Code 342. Montana NRCS code to follow when planting in critical areas.

Prodgers, Richard, 2006. Overview of Current Conditions and Remediation and Restoration 

Considerations for Mount Haggin and Section 36 on Stucky Ridge. Big Horn Environmental 

Sciences. July 2006. Available at: Remediation and restoration activities at Stucky Ridge.

Sainger, P.S., R. Dhankhar, M. Sainger, A. Kaushik, and R.P. Sing. 2011. Assessment of heavy 

metal tolerance in native plant species from soils contaminated with electroplating effluent. 

Ecotoxicology and Environmental Safety. 74: 2284-2291.

Scianna, J., Jacobs, J., St. John, L. USDA-NRCS. April 2011. Plant Materials Technical Note, MT67. Seed Source Selection, Use of Certified Seed, and Appropriate Seed Release Class Improve 

Conservation Planting Success. Available at: Seed certification classes.
NRCS−Montana−Technical Note−Plant Materials−MT-99 15

Addendum 1. Comparative Evaluation Planting − Stucky Ridge / Moto-X Replicated Mixture Trial

6/03 8/03 6/04 9/04 8/05 8/06 8/07 2004 2005 2006 2007 2004 2005 2006 2007

Species Density

No./ft2

Density

No./ft2

Stand

%

Stand

%

Stand

%

Stand

%

Stand

%

Height

in

Height

in

Height

in

Height

in

Biomass

lb./acre

Biomass

lb/acre

Biomass

lb/acre

Biomass

lb/acre

Upland 

Experimental 6.4 7.4 39.4 45.9 60.6 49.7 27.8 18.1 31.1 29.7 26.8 705.5 5,303.5 1,220.7 967.4

Upland 

Developed 9.3 7.0 17.3 24.4 25.9 35.9 27.2 5.8 18.6 22.7 27.8 192.0 1,795.8 1,592.2 1,503.2

Waste Mgmt.

Area 

Experimental

6.3 6.9 38.1 46.9 59.7 65.0 34.1 17.7 32.5 30.1 26.4 1,077.0 7,977.2 3,666.7 1,582.6

Waste Mgmt.

Area 

Developed

10.5 8.0 15.0 23.8 28.4 38.1 26.3 7.8 22.3 28.5 26.8 273.3 4,013.1 2,956.7 1,240.3
NRCS−Montana−Technical Note−Plant Materials−MT-99 16

Addendum 2. Important Characteristics of Plants in a Mine Reclamation Seed Mix

Grasses Seedling 

Vigor

Rate of 

Establishment

Cover 

Longevity

Drought 

Tolerance

Soil Texture 

Requirement 

Coarse, 

Fine, 

Medium

pH

Min / 

Max

Salinity 

Tolerance

Pollinator 

Food 

Source

Wildlife 

Food 

Source

Winter 

Forage

Regrowth 

Rate

Height 

Wildlife 

Cover

Achnatherum hymenoides

Indian ricegrass medium moderate medium high C, M 6.6 - 8.6 low N/A high high moderate high

Agrostis gigantea

redtop high rapid medium low F, M 4.5 - 8.0 low N/A high high moderate high

Bromus inermis

smooth brome high rapid high medium F, M 5.5 - 8.0 medium N/A high high slow low

Deschampsia cespitosa

tufted hairgrass low slow high low C, F, M 3.5 - 7.5 low N/A high high slow low

Elymus lanceolatus

thickspike wheatgrass medium moderate high high C, F, M 6.0 - 9.5 medium N/A high low moderate high

Elymus trachycaulus

slender wheatgrass 

(Copperhead)

high rapid low high F, M 5.6 - 9.0 medium N/A high medium moderate high

Festuca ovina

sheep fescue low moderate high high C, M 5.5 - 7.5 low N/A medium high moderate low

Hesperostipa comata

needle & thread grass low rapid high high C, M 6.6 - 8.4 none N/A high high slow low

Leymus cinereus

basin wildrye (Washoe) medium moderate high high C, F, M 5.6 - 9.0 high N/A high medium moderate high

Nassella viridula

green needlegrass high slow medium low F, M 6.6 - 8.4 medium N/A medium high moderate high

Pascopyrum smithii 

western wheatgrass medium moderate high high F, M 4.5 - 9.0 high N/A medium medium moderate high

Poa alpina 

alpine bluegrass high moderate high medium C 5.0 - 7.2 none N/A medium high slow low

Poa secunda (ampla)

Sandberg bluegrass 

(Opportunity)

low moderate high medium C, M 6.0 - 8.0 low N/A medium medium slow high

Pseudoroegneria spicata

bluebunch wheatgrass high moderate high high C, F, M 6.6 - 8.4 low mid season high high moderate high

Thinopyrum intermedium 

intermediate wheatgrass high rapid low medium C, F, M 5.6 - 8.4 low N/A high medium slow high
NRCS−Montana−Technical Note−Plant Materials−MT-99 17

Addendum 2. Important Characteristics of Plants in a Mine Reclamation Seed Mix (continued)

Forbs Seedling 

Vigor

Rate of 

Establishment

Cover 

Longevity

Drought 

Tolerance

Soil Texture 

Requirement 

Coarse, 

Fine, 

Medium

pH 

Min / 

Max

Salinity 

Tolerance

Pollinator 

Food 

Source

Wildlife

Food 

Source

Winter 

Forage

Regrowth 

Rate

Height 

Wildlife 

Cover

Achillea millefolium 

western yarrow low moderate medium medium C, M 6.0 - 8.0 low early season low high moderate high

Artemisia frigida

fringed sagebrush high rapid medium high C, F, M 7.0 - 9.0 medium late season high fair slow high

Aster chilensis 

Pacific aster low slow medium medium F, M 5.9 - 8.0 high high low high slow low

Linum lewisii 

Lewis flax high moderate high medium C, M 5.6 - 8.4 low mid season medium high slow medium

Medicago sativa 

alfalfa medium rapid medium high F, M 6.0 - 8.5 medium all 

season high low rapid low

Penstemon eriantherus

fuzzytongue penstemon

(Old Works)

low slow medium high C, F, M 4.5 - 8.3 low early/mid 

season high low moderate low

Potentilla hippiana 

woolly cinquefoil low moderate high medium C, F, M 6.4 - 7.0 medium all season low low slow low

Phacelia hastata

silverleaf phacelia medium moderate high high C, M 6.1 - 7.3 none mid season low low slow low

Shrubs

Juniperus horizontalis 

horizontal juniper low moderate high low M 5.5 - 7.8 none N/A low low slow high

Krascheninnikovia lanata

winter fat high moderate high high C, F, M 6.6 - 8.5 high early season high high moderate high

Rosa woodsii

Woods' rose medium moderate high medium C, M 5.0 - 8.0 low mid 

season medium low slow high

Shepherdia argentea

silver buffaloberry

(Mill Creek)

medium moderate high medium C, M 5.3 - 8.0 high early/mid 

season medium low slow high

Symphoricarpos albus 

common snowberry 

(Prospectors)

medium slow high medium C, F, M 6.0 - 7.8 medium mid 

season high high slow high