bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycled Waste Paper Mulch Reduces Available Container N
Authors: Glenn J.S. , Gilliam C.H. , Edwards J.H. , Keever G.J. , Knight P.R.
Published: August 2020

Two experiments were conducted to determine the effects of pelletized recycled paper mulch on container plant nutrition. In experiment 1 with Petunia floribunda Hort. ‘Midnight Madness’, 9 g (0.32 oz) of Osmocote 14N-6.2P-11.6K (14-14-14) was applied over or under 2.5 cm (1 in) of recycled paper pellet mulch, or to plants with no paper mulch (control). Leachate samples were collected after microirrigation. Both treatments with paper mulch reduced nitrate (NO3-N) and ammonium (NH4-N) levels in container leachate, compared to the control 21 days after planting (DAP). Shoot dry weight was reduced 53% and 70% for plants fertilized under and over the mulch, respectively, compared to the non-mulched control. At the end of the experiment 40–48% of the total N applied over or under mulch was retained by the recycled paper mulch. In experiment 2 with Petunia grandiflora Hort. ‘Ultra Blue’, mulch and three methods of fertilizer application (over mulch, under mulch, and incorporated in the substrate) were compared. Leachate NO3-N levels were reduced 72% or 68% with fertilizer placed over or under the mulch, respectively, when compared to a non-mulched topdressed treatment 21 DAP. When fertilizer was incorporated into the substrate, paper mulch reduced NO3-N leachate levels 87% compared to the non-mulched treatment. There were no significant differences in leachate NH4-N levels with fertilizer placed over or under the mulch when compared to a non-mulched control 21 DAP. When fertilizer was incorporated into the substrate, paper mulch reduced leachate NH4-N levels 82% compared to the non-mulched control. Shoot dry weight was 84 or 49% lower with fertilizer placed over or under the mulch, respectively, when compared to the topdressed, non-mulched treatment. However, plants grown with fertilizer applied under the mulch were 213% larger than plants with fertilizer applied over the mulch. When fertilizer was incorporated into the substrate, paper mulch reduced shoot dry weight 41% when compared to non-mulched plants. There were no differences between shoot dry weights of plants grown in non-mulched treatments with topdress fertilization or fertilizer incorporated.
Effect of Transplanting on Water Relations and Canopy Development in Acer
Authors: Barton Amy J. , Walsh Christopher S.
Published: August 2020

Transplanting large-caliper trees frequently leads to poor tree growth and survival. A longitudinal study of the changes in water relations and canopy development was conducted to study this effect. Pruning and watering were used to test the recovery of maple trees following transplanting. Water potential (ψ), transpiration rate (tr), and leaf area index (LAI) were the measured dependent variables. In the summer after transplanting, date and treatment significantly affected LAI, tr and mid-day ψ in Acer truncatum. In this species, trees receiving a post-transplant pruning treatment in combination with watering did not significantly differ in tr and mid-day ψ from nontransplanted controls, although LAI did differ between these treatments. In both A. truncatum and A. tataricum ginnala, treatment and day interacted significantly on pre-dawn ψ. While the seasonal patterns differed between species, the most negative pre-dawn ψ measurements were made four months after transplanting. In the spring following transplanting, significant differences due to prior-year treatment were again measurable in mid-day ψ in leaves of A.tataricum ginnala. In that species, mid-day ψ of the transplanted control trees differed from non-transplanted controls. Transplanting led to a measurable, long-term water stress. Pruning and watering in combination partially relieved that stress. Leaf area index was markedly affected by transplanting. It is suggested that this readily-measurable variable could be useful in assessing recovery from transplant stress.
Propagation of Pennisetum setaceum ‘Rubrum’ from Cuttings
Authors: Cunliffe Bruce A. , Meyer Mary Hockenberry , Ascher Peter D.
Published: August 2020

The effect of rooting medium, indole-3-butyric acid (IBA), and node position were studied on rooting of tender purple fountaingrass, Pennisetum setaceum ‘Rubrum’. Three-hundred single-node culm cuttings were placed in a mist house in sand, peat, vermiculite, perlite, or a peat:perlite (1:1 by vol) mix. Within 42 days, 78% of the cuttings rooted, with the highest number of cuttings rooting in the peat or perlite media and the lowest number in the vermiculite medium. Cuttings from the most proximal node exhibited a significantly higher percentage of rooting and produced more roots than cuttings from more distal nodes. Rooting medium and nodal position of cutting interacted to affect root dry weight. IBA had no significant effect on rooting. Propagation of purple fountaingrass from culm cuttings offers an economically-attractive alternative to the conventional method of crown division.
Resistance of the Euonymus Anthracnose Pathogen, Colletotrichum gloeosporioides, to Selected Fungicides
Authors: LaMondia J. A.
Published: August 2020

Fifty-five isolates of C. gloeosporioides recovered from euonymus leaf spot and stem lesions from four nurseries in Connecticut were tested in vitro for fungicide resistance. Commercially formulated fungicides were added to potato dextrose agar at 0, 1, 10, 100, and 1,000 μg ai/ml, and the regression of normalized growth rate was used to determine the EC50. Isolates exhibited a range of sensitivity to benzimidazoles, chlorothalonil, and iprodione. Resistance to multiple fungicides was common, and fungicide resistant isolates were recovered from all nurseries. Forty-four of forty-eight isolates were resistant to thiophanate-methyl; twenty-nine had EC50 values over 1,000 μg ai/ml. Thirty-four isolates had EC50 values greater than 1,000 μg ai/ml chlorothalonil; only eight were less than 100 μg ai/ml. Only two isolates of C. gloeosporioides were sensitive to 10 μg ai/ml iprodione. Over 91% of isolates had EC50 values of less than 500 μg ai/ml for copper hydroxide, but the growth of four was not totally inhibited by concentrations of 1,000 μg ai/ml. All isolates tested had EC50 values less than 500 μg ai/ml ethylene-bis-dithiocarbamate (EBDC), and 94.5% were sensitive to less than 100 μg ai/ml of this fungicide. Inhibition zones developed only around disks amended with 10,000 μg ai/ml EBDC. Conidia in contact with disks amended with 10,000 μg g ai/ml EBDC for 48 hr did not germinate. After transfer to unamended media, fungal growth was inhibited after contact with 10,000 μg g ai/ml thiophanate-methyl or iprodione, but not with copper hydroxide. Management programs for euonymus anthracnose need to be developed to control both the disease and the selection of fungicide resistant isolates of C. gloeosporioides.
Management of Euonymus Anthracnose and Fungicide Resistance in Colletotrichum gloeosporioides by Alternating or Mixing Fungicides
Authors: LaMondia J. A.
Published: August 2020

Fungicidal management of anthracnose leaf spot of euonymus (Euonymus fortunei ‘Emerald 'n Gold’ or ‘Emerald Gaiety’), caused by Colletotrichum gloeosporioides, was examined. Fungicide resistance was present in the pathogen population. Weekly applications to foliage for 12 weeks to the same plants in 1997 and 1998 of: thiophanate-methyl alone; or thiophanate-methyl, chlorothalonil, ethylenebis-dithiocarbamate and copper applied sequentially; or mixtures of thiophanate-methyl plus chlorothalonil alternated weekly with thiophanate-methyl plus ethylene-bis-dithiocarbamate were applied. Applications of the same treatments, azoxystrobin, or each of the above fungicides alone were applied at biweekly intervals in 1999. Unsprayed plants served as controls. Percent defoliation was lowest for fungicide mixtures (thiophanate-methyl plus chlorothalonil alternated with thiophanate-methyl plus ethylene-bis-dithiocarbamate) and was highest for unsprayed controls and plants treated with thiophanate-methyl alone. The average number of lesions per 100 leaves was lower for mixed and sequential fungicide programs than for untreated or thiophanate-methyl alone spray programs. Emerald 'n Gold had more lesions per leaf than Emerald Gaiety, but the level of defoliation was greater for Emerald Gaiety. Fungicide-resistant C. gloeosporioides isolates, which were recovered on media amended with thiophanate-methyl or with chlorothalonil, were in lowest frequency from plants treated with the mixed fungicide program. Management of euonymus anthracnose and fungicide resistance in C. gloeosporioides may be achieved by applying fungicide mixtures with different modes of action.
Preemergent Bittercress Control on a Gravel Groundcover
Authors: Briggs Jeanne , Whitwell Ted , Riley Melissa B. , Smith Russell , Legnani Garry
Published: August 2020

Bittercress (Cardamine hirsuta) is a problem weed year round in Southeastern U.S. container nurseries. It readily establishes itself on gravel production surfaces and in containers, producing seeds in 4 to 5 weeks. Gravel has limited adsorption sites for herbicides, and higher use rates are required for control. Many preemergent herbicides provide short-term (3 month) control of bittercress. Sprayable formulations provided more persistent control than granular formulations. Factor (prodiamine) and Goal (oxyfluorfen) controlled bittercress for 8 months at 2× normal rates under nursery conditions of daily irrigation. Half-lives of Factor and Goal were 3 and 1 month, respectively. Extraction of herbicides from the gravel indicated that bittercress was controlled by 0.31 ppm of both herbicides.
The Effect of Mulch Type for Turfgrass Establishment within a Refined Wood Fiber Mat over Plastic
Authors: Sorochan J.C. , Rogers J.N.
Published: August 2020

The germination and establishment of perennial ryegrass and supina bluegrass within a refined wood fiber mat (Ecomat®) placed on plastic sheeting was evaluated using seven mulches and a control with no mulch. Percent turfgrass cover (0–100%) was visually estimated as a measure of seedling density at 7, 14, 21, and 28 days after seeding. Three field experiments were initiated on July 3, 1995, September 29, 1995, and July 5, 1996. The three seeding dates were chosen to show the effects of mulches under optimal and suboptimal growing conditions for cool season turfgrasses. The seven mulches consisted of hydrated fiber mulch, copolymer of sodium acrylamide, crumb rubber, straw, fine grade compost, pelletized fiber mulch, and a native Capac loam soil. Percent turfgrass cover differed among species for the seven mulch treatments and the control, and the three seeding dates. Overall, perennial ryegrass achieved 25% greater cover than supina bluegrass. The straw, pelletized fiber mulch, and hydrated fiber mulch resulted in the greatest turfgrass cover regardless of seeding date. Crumb rubber performed equal to these mulches only during the 29 September 1995 seeding trial. In summary, the use of a particular mulching material will enhance turfgrass cover during seed germination.
Growth Regulation of Sub-Tropical Perennials by Photoselective Plastic Films
Authors: Wilson Sandra B. , Rajapakse Nihal C.
Published: August 2020

Plant response to photoselective plastic films with varying spectral distribution properties was tested using three sub-tropical perennials: golden shrimp plant (Pachystachys lutea), Persian shield (Strobilanthes dyerianus), and cat whiskers (Orthosiphon stamineus). Films were designated YXE-10 [far-red (FR) light-absorbing film] and SXE-4 [red (R) light absorbing film]. Light transmitted through YXE-10 films reduced plant height (stem length) of golden shrimp plant and cat whiskers by 10 and 20%, respectively. Light transmitted through SXE-4 films increased plant height by 9% for golden shrimp plant but did not significantly increase stem length of Persian shield and cat whiskers species. Chlorophyll, leaf area, and mean days to flower generally were not affected by photoselective films, with the exception that cat whisker plants grown under YXE-10 films had reduced leaf area when compared to plants grown under SXE-4 or control films. As compared to the control film, light transmitted through YXE-10 films reduced leaf dry weight by 22–31% and stem dry weight by 19–28%, depending on the plant species. Root dry weight was not affected by spectral films.
Growth Responses of Chemically Root-pruned Cork Oak Seedlings in the Nursery
Authors: Pardos M. , Pardos J.A. , Montero G.
Published: August 2020

Cork oak (Quercus suber L.) seedlings of two Iberian provenances (PA-SR and SM-Lp) were grown for one growing season in non-treated containers or in containers treated on their interior surfaces with white exterior latex paint containing 80 g CuCO3/liter. Copper carbonate-treated containers effectively prevented root deformation and decreased the amount of circled, kinked and matted roots formed at the container wall-medium interface. Root morphology was altered by the copper coating, so elongation of lateral roots contacting CuCO3-treated surfaces was more reduced than that of the tap root (82.7% vs 1.5%). These lateral roots showed higher branching frequency than roots contacting untreated container walls. CuCO3 treatment decreased root collar diameter, but did not influence seedling height, leaf area and tap root length. No sign of copper toxicity was observed in any seedling treated with CuCO3. Provenance had a significant effect on height, root collar diameter, tap root length and root weight per unit length; these results may reflect differences in growth habit of the two provenances. Other growth parameters measured were affected by a copper × provenance interaction. Seedlings of the PA-SR provenance produced less root and plant dry wt when grown in CuCO3-treated than in control containers, but shoot:root ratio was not influenced.
Influence of Mulch Characteristics on Sporulation by the Artillery Fungus Sphaerobolus stellatus
Authors: Brantley Elizabeth A. , Davis Donald D. , Kuhns Larry J.
Published: August 2020

The artillery fungus (Sphaerobolus stellatus) is a common, white-rotting wood decay fungus that grows on landscape mulch. During colonization, the fungus produces dark-brown, sticky spore masses (gleba) that it shoots from the mulch towards a source of light or light-colored objects. The gleba adhere tightly to surfaces such as the sides of houses or cars. Twenty-five landscape mulches were evaluated in the field and laboratory to determine which mulches supported or inhibited the artillery fungus. Although the artillery fungus eventually grew on most types of mulch, some mulches supported more sporulation than others. The artillery fungus did not grow or sporulate well on mulches made from large pine bark nuggets, Atlantic white-cedar, or cypress. We recommend these mulches for use in areas having an existing or potential artillery fungus problem. However, even these mulches should be replaced with new mulch on a regular basis.
Soil Applied Paclobutrazol Affects Root Growth, Shoot Growth, and Water Potential of American Elm Seedlings
Authors: Watson Gary W.
Published: August 2020

Paclobutrazol (PBZ), a gibberrellin biosynthesis inhibiting plant growth regulator, was applied as a soil drench to potted American elm (Ulmus americana L.) seedlings in three greenhouse experiments. All plants were grown for one season in a #SP5 container and then transplanted to a larger #5 container before PBZ application in order to simulate planting in the landscape. In a test of the effects of PBZ on growth, a rate of 1.0 mg per plant reduced new shoot weight, shoot extension, and root weight (75, 38 and 63 percent, respectively) compared to controls, but new root elongation was unaffected. Root pruning, similar to that which occurs when transplanting fieldgrown nursery stock, resulted in a greater decrease in shoot growth from PBZ treatment at the moderate rate of 1.0 mg per plant, but for a shorter period of time, compared to non-root pruned, PBZ-treated plants. Shoot growth on all plants was unaffected by 0.5 mg PBZ, per plant. Shoot growth was greatly reduced on both root pruned and non-root pruned plants at 2.0 mg PBZ per plant. After 10 weeks of drought stress, stem water potential of elms treated with 1.0 mg PBZ per plant was the same as that of the well watered controls, whereas the stem water potential of drought-stressed elms lacking a PBZ treatment was significantly lower (more negative). These effects of PBZ may be able to aid in the establishment of newly planted trees.
Factors Influencing Revenues of the Landscape and Lawn Care Companies
Authors: Anil S. K. , Florkowski W. J. , Epperson J. E. , Landry G.
Published: August 2020

The purpose of this study was to determine the impact of key factors influencing the landscape maintenance and lawn care industry (LM/LC) sales or gross revenue as well as partial net revenue (gross revenue less labor cost). A single-equation framework was applied for the estimation of gross and partial net revenue models. Analysis showed a positive influence of labor cost on gross revenue. In comparison to individually owned firms, corporations can expect larger revenue increases. Companies with extended business experience (measured by the number of years in operation) could expect not only greater gross revenue but also greater partial net revenue. The level of education of supervisory personnel was specifically important for partial net revenue. Offers of price discounts for services enhanced gross revenue but not partial net revenue. Price discounting may help in the management of labor and cash flow in the short run, but the LM/LC company must recover overhead costs to stay in business. Population density continues to play a major role in improving the revenues of LM/LC companies.
Evaluation of Asian, European, and North American Elm (Ulmus spp.) Biotypes To Feeding by Spring and Fall Cankerworms
Authors: Miller Fredric , Malmquist Kimberly , Ware George
Published: August 2020

Nearly 40 different Asian elm (Ulmus spp.) biotypes, growing at The Morton Arboretum, Lisle, IL, were evaluated in laboratory bioassays and in the field for suitability and feeding preference of the spring cankerworm Paleacrita vernata (Peck) and the fall cankerworm, Alsophila pometaria (Harris). No-choice and multiple-choice laboratory feeding studies, and field defoliation surveys revealed that U. castaneifolia, U. changii, U. chenmoui, U. davidiana, U. elongata, U. gaussenii, U. glaucescens var. lasiophylla, U. japonica, U. lamellosa, U. lanceaefolia, U. macrocarpa, U. parvifolia, U. propinqua, U. propinqua var. suberosa, U. prunifolia, U. pseudopropinqua, U. taihangshanensis, U. wallichiana, U. wilsoniana, U. wilsoniana-98, and the simple and complex hybrids U. davidiana x U. japonica, U. davidiana x U. propinqua, U. japonica x U. ‘Morton’-Accolade™, U. ‘Morton’-Accolade™ x U. japonicapumila, U. ‘Morton Glossy’-Triumph™, and U. ‘Morton Plainsman’-Vanguard™ x U. davidiana, were less suitable for larval development and pupation and less preferred by spring and fall cankerworm larvae. Ulmus americana, U. glaucescens, U. szechuanica, and the simple and complex hybrids U. davidiana x U. ‘Morton’-Accolade™, U. szechuanica x U. japonica, U. ‘Morton’-Accolade™, U. ‘Morton Red Tip’-Danada Charm™ and U. ‘Morton Plainsman’-Vanguard™ were more suitable for and more preferred by spring and fall cankerworm larvae. Rankings for larval development time were highly correlated with larval longevity, but the proportion of larvae pupating was correlated neither with larval longevity nor with larval development time. Pupal fresh weights also were correlated neither with larval longevity nor with larval development time. Mean fecal pellet weights were correlated with the proportion of larvae pupating, but were not correlated with pupal fresh weights. Ulmus chenmoui, U. glaucescens var. lasiophylla, U. lamellosa, U. macrocarpa, U. propinqua, U. prunifolia, and U. pseudopropinqua all showed medium to heavy leaf pubescence and were less suitable and less preferred by spring and fall cankerworms. Asian elms were least preferred by cankerworm larvae, followed in order of increasing preference by European and North American elms.
A Water and Nutrient Management Planning Process for Container Nursery and Greenhouse Production Systems in Maryland
Authors: Lea-Cox John D. , Ross David S. , Teffeau K. Marc
Published: August 2020

Many states throughout the United States are now concerned about the impact of non-point source pollution on the declining quality of water in their watersheds. In 1998, the state of Maryland adopted one of the toughest nutrient management planning laws in the nation, requiring virtually all agricultural operations to write and implement nitrogen (N) and phosphorus (P) based management plans by December 31, 2002. The nursery and greenhouse industries are faced with a complicated task to write these nutrient management plans, since these operations grow a large number of plant species utilizing a range of fertilization and irrigation strategies. A nutrient management planning strategy has been identified that will provide an assessment of nutrient loss potential from a wide variety of production scenarios, identify the specific factors that contribute most to nutrient leaching and runoff, and enable targeted best management practices to be implemented to reduce the risk of nutrient run-off.
Effect of CuCO3 Container Wall Treatment and Mycorrhizae Fungi Inoculation of Growing Medium on Pine Seedling Growth and Root Development
Authors: McDonald S.E. , Tinus R.W. , Reid C.P.P. , Grossnickle S.C.
Published: August 2020

Coating the inside surfaces of containers with cupric carbonate (CuCO3) stopped lateral root growth of ponderosa pine (Pinus ponderosa Laws.) and lodgepole pine (Pinus contorta Dougl.) at the container wall. Subsequent higher order laterals proliferated and were similarly arrested. The CuCO3 treatment was compatible with inoculation of the growing medium with the mycorrhizae fungi Pisolithus tinctorius (Pers.) Coker and Couch and Suillus granulatus (L. ex. Fr.) O. Kuntze. Combined inhibitor—inoculum treatments resulted in pine seedlings that were bigger, had more lateral roots, and greater mycorrhizal infection rates than untreated seedlings.
Influence of Trickle Irrigation and Nitrogen Rates to Acer rubrum L.
Authors: Ponder Harry G. , Gilliam Charles H. , Wilkinson Emmett , Eason John , Evans Clyde E.
Published: August 2020

Water was applied at flow rates of 0, 3.8 and 7.6 liters per hour (0, 1 and 2 gph) and nitrogen (N) was surface applied at 50, 100, 200, and 300 kg/ha (45, 90, 180 and 270 lbs/A) in 1981 and 1982 to Acer rubrum (L.). Tree height, trunk caliper and root dry weight within an AAN specified size were greater with trees grown with 3.8 l/h (1 gph) compared to non-irrigated trees. Tree height and trunk caliper were not affected by N rate. Nitrogen rate influenced root growth. Roots of red maples grown with 3.8 l/h (1 gph) and 200 kg/ha (180 lbs/A) of N were more concentrated under the tree.
Effect of Timed Fertilizer Application on llex crenata ‘Helleri’ cuttings during propagation
Authors: Booze-Daniels J.N. , Wright R.D. , Lyons R.E.
Published: August 2020

The effect of timed fertilizer applications on growth of Ilex crenata ‘Helleri’ cuttings was examined. At termination of the experiment, cuttings initially fertilized soon after roots were visible (week 4) were larger than cuttings for which fertilization was either delayed or withheld. Delaying the initiation of fertilization at weekly intervals after roots were visible resulted in lower dry weight per cutting as the delay in fertilization increased. Nitrogen (N) was found to accumulate in cuttings immediately after roots were first visible but not before. Fertilization before root appearance was of little practical benefit.
Effects of Nitrogen Concentration and Container Size on Growth of Pyrus calleryana ‘Bradford’
Authors: Gilliam Charles H. , Cobb Gary S. , Evans Clyde E.
Published: August 2020

The influences of N concentration in the irrigation water and container size on growth of ‘Bradford’ pear were studied. Container size influenced growth more than N rates. Trees grown for 2 years in 38 and 57 liter (#10 and #15) containers were greater in height and caliper than trees grown in 19 liter (#5) containers. Trees fertilized with 300 ppm N weekly had similar height but greater caliper compared to plants fertilized with 150 ppm N weekly. N rates above 300 ppm N were not beneficial. Production costs and profitability are discussed.
Updating Landscape Specifications
Authors: Gouin Francis R.
Published: August 2020

Changes in nursery growing practices, combined with an increasing number of untrained people entering the landscape contracting industry, has necessitated the development of landscape specification guidelines so detailed that individuals with minimal horticultural skills should be able to complete a landscape project successfully. Emphasis in guidelines must be placed on shallow planting, the cutting of outside roots of container grown plants to minimize root girdling and to encourage rapid establishment, soil pH requirements of plants, soil drainage specifications in relation to planters and in special landscape situations, mulching materials and problems associated with over-mulching, stem girdling by ties and marking tapes, emphasis on root hardiness especially in relation to raised outdoor planters, learning to recognize properly dug large plants and the importance of plant nutrition.
Growth, Dry Weight and Nitrogen Distribution of Red Oak and ‘Autumn Flame’ Red Maple Under Different Fertility Levels
Authors: Larimer Jill , Struve Daniel
Published: August 2020

Red oak (Quercus rubra L.) seedlings and ‘Autumn Flame’ red maple (Acer rubrum L.) rooted cuttings were grown under different fertility levels: 0, 25, 50, 100, 200 or 400 mg/liter N from 20N–8.6P–17K water soluble fertilizer applied daily in two, 45-minute irrigation events. At one-month intervals from June to October, seedlings were harvested, and dry weights and N content of leaves, stems and roots determined. In October, red oak dry weight increased up to 400 mg N/liter fertigation. Red maple dry weight was greatest between 200 and 400 mg N/liter fertigation. For both species, as N fertigation level increased, relative stem dry weight increased while relative root dry weight decreased. There was little change in relative leaf dry weight. For both species, percent N in leaf, stem and root tissues increased with increasing N fertigation. N distribution in leaf, stem and root tissues was similar to relative dry weight accumulation. Red maple plants had greater morphological adjustment to increasing N fertigation than did red oak plants. At the highest fertigation levels, red maple plants could be N loaded, increasing N tissue concentrations without an increase in plant dry weight. Red oak plants did not exhibit N loading.
A Geographic Assessment of the Risk of Naturalization of Non-native Woody Plants in Iowa
Authors: Widrlechner Mark P. , Iles Jeffery K.
Published: August 2020

The objective of this study was to determine whether patterns of native distributions of naturalized woody plants and their relationships to climatic analogs can serve as a sound basis to help identify high-and low-risk regions from which to introduce new woody plants to Iowa. We compared the native ranges of 28 non-native species naturalized in Iowa with those of 72 different, non-native species widely cultivated in Iowa, but with no record of naturalization. From this comparison, we tested two related hypotheses: (1) regions with the highest number of native species that have naturalized in Iowa have a significantly higher proportion of naturalizing species than predicted by the overall ratio of the number of naturalizing species to the total number of non-native species studied; and (2) regions identified as climatic analogs to Iowa conditions, based on important determinants of woody plant adaptation, have a significantly higher proportion of naturalizing species than predicted by the overall ratio of naturalizing species to the total number of non-native species studied. We discovered that the two regions with the highest number of naturalizing species (in southeastern Europe and northeastern China) have a significantly higher proportion of naturalizing species than would be predicted by chance alone. Two of the five regions identified as climatic analogs to Iowa conditions (in northeastern and central Asia) also displayed significantly higher proportions of naturalizing species, while a third (in southeastern Europe) was statistically significant only at the 10% level.
Production Techniques for Highrise™ and Seedling Live Oak
Authors: Gilman Edward F. , Stodola Ann , Marshall Michael D.
Published: August 2020

Cutting propagated Quercus virginiana ‘QVTIA’ Highrise™ PP #11219 and seedling live oak required the same amount of time to prune to a dominant leader in the nursery. Highrise™ live oaks were more uniform in caliper, height and root ball characteristics than the seedling crop. Finished seedling trees had larger caliper than cutting propagated Highrise™ but height was similar. Root pruning horizontal roots alone or in combination with placing root pruning fabric under the liner at planting reduced dry weight of roots in the root ball by reducing large-diameter root weight and increasing small-diameter root weight. Trees produced by both methods of root pruning survived the digging process better than non root-pruned trees in the summer digging season. Seedlings had more root weight in the root ball and a higher root: shoot ratio than Highrise™ live oak. But Highrise™ had a 45% greater small diameter root: shoot ratio than seedling live oak, and more Highrise™ survived the digging process than seedlings. Highrise™ may not need root pruning during production if dug in the dormant season.
Effect of Tree Shelters on Growth and Gas Exchange of Four Tree Species Under Field and Nursery Conditions
Authors: West D.H. , Chappelka A.H. , Tilt K.M. , Ponder H.G. , Williams J.D.
Published: August 2020

One-year-old seedlings of sawtooth oak, white oak, green ash and flowering dogwood were evaluated to determine the effect of tree shelters on survival, growth and gas exchange. Trees were grown under both field and container nursery conditions. Shelters had a significant impact on survival of field-grown trees, but not on containerized, nursery-grown seedlings. Overall survival was approximately 75 and 40% for sheltered and non-sheltered, field-grown trees, respectively. Sheltered plants had approximately a 90% survival rate and non-sheltered trees exhibited approximately 80% survival in a nursery situation. In the field, sheltered trees had greater height growth and biomass production than non-sheltered trees. However, sheltered plants exhibited a decrease in total biomass in the nursery study, the majority of which was reflected in an overall 62% reduction in root production in the sheltered trees. Photosynthesis of sheltered trees averaged 65% of non-sheltered trees and internal leaf CO2 was approximately 11% greater in sheltered trees. Shelters appear to benefit field-planted seedlings by providing physical protection and shade therefore, enabling the tree to better survive stresses from ambient conditions. In nursery situations, shelters may only be helpful in training attractive trees with less labor.
Growth of Several Tree spp. in Containers in Response to N Loading, Fertilizer Type and Substrate
Authors: Struve Daniel K.
Published: August 2020

Two studies were conducted to determine if Comtil, a composted municipal sewage sludge, could be used as a substrate component and a slow release N source in a containerized whip production system and to determine the growth potential of nine tree species not widely grown in the industry. Also, in the second study the effects of fertilizer type on five oak species were studied. In the first study, total N from Comtil was estimated to be 64 gm per No. 3 nursery container, representing between 48 and 100% of the N loading. Despite the potential high N loading from Comtil, tree height was unaffected. No simple fertilizer treatment consistently produced the tallest plants for the four species studied. Fertilizer type affect growth of only two species (Q. macrocarpa and Q. muehlenbergii) and then only in the first year of the two year study. There were significant differences in height growth among the six Q. alba sources. The nine tree species in this study could be grown in 3:1 (by vol) pine bark: coir and pine bark: Comtil substrates.
Flowering Performance of 21 Hydrangea macrophylla Cultivars
Authors: Reed S.M.
Published: August 2020

The flowering performance of 21 Hydrangea macrophylla cultivars was evaluated for three years at two locations. Ten plants of each cultivar were planted during 1997 in field plots at McMinnville, TN (USDA hardiness Zone 6b), and New Franklin, MO (USDA hardiness Zone 5b). The number of inflorescences was recorded every two weeks from May through September in 1999, 2000 and 2001. Daily maximum and minimum temperatures were recorded from October 1998 through September 2001. Differences among cultivars were found all three years at McMinnville and in 1999 and 2000 in New Franklin. While rankings of cultivars for number of inflorescences differed among years and locations, ‘All Summer Beauty’ and ‘Nikko Blue’ were consistently among the best performing cultivars. ‘Blauer Prinz’, ‘Blue Wave’, ‘Mariesii’ and ‘Todi’ flowered poorly all 3 years at both locations. No cultivar flowered reliably all three years of the study. Although some cultivars flowered sporadically throughout the summer, no remontant cultivars were identified. Poor flowering performance during the study appeared to be related to damage to aboveground portions of plants from a combination of early fall freezes, low winter temperatures and late spring freezes.
Timing of Low Pressure Irrigation Affects Plant Growth and Water Utilization Efficiency
Authors: Warren Stuart L. , Bilderback Ted E.
Published: August 2020

Pine bark based substrates, commonly used in the southeastern United States for container nursery crop protection, have low moisture retention properties; therefore, daily irrigation during the growing season is required to maximize plant growth. Current guidelines state that irrigation should occur during the early morning hours (before 1000 HR). However, limited research indicated that multiple application of water each day resulted in significantly more growth compared to early morning application. The objective of these studies was to evaluate the effects of irrigation timing on plant growth, photosynthesis, water utilization efficiency, and substrate temperature. In experiment 1, the daily total volume of irrigation required to maintain 0.4 leaching fraction (LF) in the early morning application (0300, 0500, and 0700 HR) was divided into three equal parts and applied at the following times: 0300, 0500, and 0700 HR; 1200, 1500, and 1800 HR; 0900, 1200, and 1500 HR; and 0500, 1200, and 1900 HR. In experiment 2, the daily total volume of irrigation to maintain 0.15 LF within each timing was divided into three equal parts and applied at the following times: 0200, 0400, and 0600 HR; 0600, 0900, and 1200 HR; 1200, 1500, and 1800 HR; and 0600, 1200, and 1800 HR. Irrigation applied at 1200, 1500, and 1800 HR produced 57% and 69% greater total plant dry weight in experiments 1 and 2, respectively, compared to plants irrigated during early morning hours. Root: top ratio was unaffected by irrigation timing. In both experiments, irrigation applied at 1200, 1500, and 1800 HR had higher water utilization efficiency compare to irrigation applied at 0300, 0500, and 0700 HR or 0600, 0900, and 1200 HR. In experiment 2, plants irrigated at 1200, 1500, and 1800 HR maintained higher rates of net CO2 assimilation and stomatal conductance, and lower substrate temperatures from 1800 to 2200 HR compared to plants irrigated at 0300, 0500, and 0700 HR or 0600, 0900, and 1200 HR.
Stem and Leaf Hardiness of 12 Abelia Taxa
Authors: Scheiber S.M. , Robacker Carol D. , Lindstrom Orville M.
Published: August 2020

Twelve taxa of Abelia were evaluated using laboratory procedures to determine maximum stem and leaf hardiness and to evaluate timing of acclimation and deacclimation over a two-year period. Among the 12 Abelia taxa evaluated, ‘John Creech’ was among the hardiest taxa for both stems and leaves on the majority of test dates. Stems and leaves of ‘John Creech’ survived to at least −26C (−15F) and −21C (−6F), respectively, in January 2001. ‘Edward Goucher’ and ‘Confetti’ had the least hardy stems and leaves, respectively. Stems of ‘Edward Goucher’ survived to at least −16C (3F) in January 2000, and ‘Confetti’ leaves survived to only −14C (7F) in December 2000. Abelia × grandiflora consistently ranked among the first to attain cold hardiness in the fall and among the last to lose cold hardiness in the spring in both test seasons. Stems were equal in hardiness or hardier than leaves on the majority of test dates in both test seasons. Laboratory results were consistent with field observations, but often differed from published hardiness ratings. Differences in lowest survival temperatures and attainment and retention of cold hardiness closely followed temperature fluctuations just prior to sampling dates.
Antitranspirant Treatments of Stock Plants do not alter Growth and Adventitious Rooting of Shoots of ‘Montaigne’ Lilac and White Fringetree
Authors: Switras-Meyer Susan M. , Gillman Jeffrey H.
Published: August 2020

Antitranspirants were evaluated for their effectiveness as a stock plant treatment to improve adventitious rooting of softwood cuttings of Syringa vulgaris L. ‘Montaigne’ (Montaigne lilac) and Chionanthus virginicus L. (white fringe tree). New shoots of S. vulgaris ‘Montaigne’ and C. virginicus were sprayed with one of two film-forming antitranspirants including Clear Spray® (aqueous acrylic emulsion) and sodium silicate; or Atrazine®, a herbicide that acts as a stomate-regulating antitranspirant. Shoot caliper of antitranspirant-treated lilacs increased more slowly than controls. Thirty days after treatment cuttings were taken from both taxa. All treatments resulted in 80 to 85% rooting of cuttings in lilac after 6 weeks, but cuttings from Clear Spray®-treated plants rooted more quickly. Chionanthus virginicus cuttings treated with Clear Spray® had significantly lower rooting (16%) than cuttings taken from Atrazine® treated plants (50%). In a subsequent experiment, antitranspirant treatment had no significant effect on shoot length or caliper of ‘Montaigne’ lilac. Photosynthetic rate, transpiration rate, and location of cutting on the stock plant were all positively correlated with shoot length, shoot caliper, and cutting diameter. Shoot length and caliper and cutting diameter, however, were all negatively correlated with root number and root length. There were no significant treatment effects on rooting percentage, root number or root length.
The Efficacy of Ectomycorrhizal Colonization of Pin and Scarlet Oak in Nursery Production
Authors: Martin T.P. , Harris J.R. , Eaton G.K. , Miller O.K.
Published: August 2020

Two experiments were conducted to assess the effectiveness of ectomycorrhizae inoculation of pin (Quercus palustris) and scarlet oak (Q. coccinea) during nursery production. Experiment 1 tested inoculum and substrate protocol. Vegetative and spore inoculum of Pisolithus tinctorius (Pt) were applied to pin and scarlet oak seedlings. All plants were grown in 0.9 liter (1 gal) containers filled with milled pine bark, sterilized milled pine bark, sterilized mineral soil, or sterilized vermiculite-based substrate. After two months, mycorrhizal colonization rates were assessed qualitatively. Vegetative inoculum was unsuccessful at infecting seedlings of both species when grown in all of the substrates. Best results were 90% and 60% of plants colonized with spore inoculum for pin and scarlet oak, respectively, grown in vermiculite-based substrate. Sixty percent of pin oaks were colonized by Pt in milled pine bark, whereas no scarlet oaks were colonized. Overall, the spore inoculum colonized pin oak at a higher rate than scarlet oak, and vermiculite-based substrate proved superior to the other three substrates for inoculating seedlings with commercial Pt spores. In experiment 2, Pt spore inoculum was applied as a bare root dip on scarlet oak liners before transplanting into 51 liter (15 gal) containers in a pot-in-pot growing system. Pt had a colonization rate of zero, but an indigenous mycorrhizal fungus, Scleroderma bovista (Sb), colonized many of the trees. Height and trunk diameter growth during two years of production were similar for trees colonized and not colonized with Sb. Leaf water potentials were more negative and stomatal conductance was reduced for transplanted colonized compared to not colonized trees during a 10-day dry-down, imposed 50 days after transplanting. Under our conditions, mycorrhizal fungi showed no apparent benefit during production and during initial establishment.
Impact of Water Treatment on Foliar Damage of Landscape Trees Sprinkle Irrigated with Reuse Water
Authors: Devitt D. A. , Morris R. L. , Neuman D. S.
Published: August 2020

An experiment was conducted on four container-grown tree species placed under five different irrigation reuse water treatments to determine the extent of foliar damage after a 14.5-month period. The tree species included Heritage oak (Quercus virginiana Mill. ‘Heritage’), desert willow (Chilopsis linearis (Cav.)/Sweet), flowering plum (Prunus cerasifera Ehrh ‘Atropurpurea’), and Chinese pistache (Pistacia chinensis Bunge). Plant response and an index of visual damage (IVD) were assessed at different times throughout the experiment. Ion concentrations in the leaf tissue were different for species (S) (p < 0.001), treatment (T) (Na, K, SO4, p < 0.05) and by a species by treatment interaction (S × T) (Na, Ca, Mg, K and SO4, p < 0.05). SPAD measurements varied by S (p < 0.001), T (p < 0.001) and by an S × T interaction (p < 0.045). SPAD measurements decreased as the leaf tissue Na concentration increased (SPAD = 47.49 – 12.46(Na), r2 = 0.38, p < 0.01). The IVD varied by S (p < 0.001), T (p < 0.001) and by an S × T interaction (p < 0.001). Na, Ca and SO4 tissue ion concentrations could account for 52% of the variability in the IVD (IVD =−1.93 + 4.63(Na) + 2.60(Ca)−0.001(SO4), p < 0.01). Because the irrigation treatment resulting in the lowest IVD was species dependent, irrigation treatment selection should be based upon an evaluation of the landscape species composition and the potential cost of implementing a given strategy. The response observed in this study suggests that a single universal irrigation strategy does not exist, indicating that emphasis must be placed on initial and replacement plant selection.
Evaluation of Suction Cup Lysimeters for Obtaining Substrate Solution from a Pine Bark Substrate
Authors: Stanley Mary , Harris Roger , Scoggins Holly , Wright Robert
Published: August 2020

Protocols are needed for extracting the container substrate solution of plants in large containers [≥ 18.9 liter (#5)] since the container substrate solution is representative of the nutrients available to the plants. The objective of this study was to determine the effectiveness of suction cup lysimeters (SCLs) for this purpose. The lysimeter types tested were those with a 4.8 cm (1.9 in) diameter and a ½ bar or 1 bar air-entry value (AEV) and those with a 2.2 cm (0.87 in) diameter also with a ½ bar or 1 bar AEV. A sufficient volume of the substrate solution could be obtained after 5 min when a vacuum pressure of 30, 40 or 50 kPa was applied to 4.8 cm (1.9 in) ½ bar lysimeters. The 2.2 cm (0.87 in) lysimeters were suitable for extracting smaller sample volumes of solution or if installation space was limited. Electrical conductivity (EC) levels were unaffected by volume of substrate solution extracted by the SCL when volumes varied from 10 to 190 ml (0.34 to 6.4 oz). Overall, the 4.8 cm (1.9 in) diameter lysimeters are recommended for use with large nursery containers.
A Comparison of Irrigation System, Basal Temperature and Auxin Concentration on Rooting of Stem Cuttings of Ilex glabra L.
Authors: Owen James S. , Johnson William A. , Maynard Brian K.
Published: August 2020

Basal stem temperature and auxin treatment effects on rooting percentage, root number, length of the longest root, and basal stem necrosis of hardwood stem cuttings of Ilex glabra L. (inkberry holly) were compared between a recirculating subirrigation propagation system and a conventional intermittent mist propagation system. Recirculating subirrigation maintained basal temperature and medium moisture content better than conventional intermittent mist. While rooting percentages were significantly greater for cuttings rooted in the recirculating subirrigation system, root number, and length of the longest root were higher for cuttings rooted under intermittent mist. A basal temperature of 32C (90F) was supra-optimal, resulting in significantly lower rooting percentages. However, rooting temperature had no effect on root number or basal stem necrosis. Basal stem necrosis of rooted cuttings was greater in the recirculating subirrigation system, and increased with temperature in both irrigation treatments, but appeared to have no significant effect on root number. Increasing auxin concentration increased rooting percentage, root number, and length of the longest root of rooted cuttings, though the response differed with irrigation treatment. Cuttings of Ilex glabra L. can be rooted successfully in a recirculating subirrigation propagation system where the rooting process appears to be less sensitive to rooting temperature and auxin concentration than for cuttings rooted under intermittent mist. However, overall root growth was greater on cuttings rooted under intermittent mist, perhaps because of the lower medium moisture content in that system. This suggests that optimal rooting of hardwood cuttings can be achieved without intermittent mist using a recirculating subirrigation system with modifications to the moisture content of the rooting medium.
Seed Source Affects Flowering and Growth of Container-Grown Black-Eyed Susan (Rudbeckia hirta L.)
Authors: Norcini Jeffrey G. , Aldrich James H.
Published: August 2020

Rudbeckia hirta, black-eyed susan, is a popular container-produced native wildflower. However, there is a growing demand for regionally adapted selections because of ecological and sustainability issues. In separate studies in 2001 and 2002, seed from three sources — north Florida (NFL), central Florida (CFL), and Texas (TEX)—were sown in the greenhouse in mid-January. Seedlings were transplanted to cell packs in early February. In early April, liners were potted in 2.5 liter (0.66 gal) containers and placed on an outdoor production bed under full sun. Full bloom occurred about 21.5 to 23 weeks after sowing. TEX achieved full bloom 10 days earlier than NFL or CFL. Except for CFL in 2001, most plants were of a commercially acceptable height. The most uniform growth or flowering trait based on coefficients of variation was date of full bloom, with date of first bloom just slightly more variable. Other growth and flowering traits were moderately to highly variable.