bluuebunny/crossref_metadata_2025 huggingface dataset:
Nodulation and Nitrogen-fixing Capacity of Rhizobial Isolates from China in Symbiosis with Maackia amurensis
Authors: Schrader James A. , Kroggel Mark , Graves William R.
Published: August 2020

Maackia amurensis Rupr. & Maxim (Amur maackia) is a leguminous Asian tree capable of forming N2-fixing symbioses with soil-borne Bradyrhizobium spp. This trait sets Amur maackia apart from many legumes now produced in North American nurseries. Two determinants of N2-fixing capacity in legumes are the compatibility of the host plant and its bacterial microsymbiont and the metabolic efficiency of compatible bacteria. Our objectives were to isolate numerous rhizobia from the root zones of indigenous Amur maackia in China and to select isolates that form superior N2-fixing relationships with inoculated seedlings. Soil samples collected in the Heilongjiang Province of China were used as inocula to establish nodules on seedlings. Putative rhizobia were isolated from these nodules and cultured. Inoculation of additional seedlings with 170 of these isolates evoked nodulation, confirming their identity as rhizobia. Isolates that induced the most nodules were evaluated further. All selected isolates increased growth and total N content of Amur maackia compared to uninoculated controls. Three of the isolates induced more root nodules, and four evoked a higher total N content in plants than did isolate USDA 4349, a previously characterized strain of Bradyrhizobium selected for Amur maackia. Our results demonstrate marked variation among rhizobia compatible with Amur maackia and illustrate the potential to inoculate plants in nurseries and landscapes with superior bacteria, a practice that could reduce fertilizer use and improve performance of trees in N-deficient soils.
Seed Germination of Seabeach Amaranth (Amaranthus pumilus) in Response to Temperature, Light, and Gibberellin A3 Treatments
Authors: Norden Daniel S. , Blazich Frank A. , Warren Stuart L. , Nash David L.
Published: August 2020

Seeds of seabeach amaranth (Amaranthus pumilus Raf.) stored at 4C (39F) for approximately 1 year (harvested September 2003) and freshly harvested seeds (October 2004) were soaked in November 2004 in solutions of the potassium (K) salt (K-salt) of gibberellin A3 (K-GA3) at 0, 100, 500, or 1000 mg/liter (ppm) for 24 hr in darkness. After treatment, seeds were germinated at 25C (77F) or at an 8/16-hr thermoperiod of 30/20C (86/68F) with daily photoperiods at each temperature of 0 (total darkness) or 16 hr. Germination was recorded every 3 days for 30 days. Stored and fresh seeds responded similarly. However, the 2003 seeds had greater viability (percent germination) and vigor (germinated faster) and these data are presented. Regardless of germination temperature and photoperiod, nontreated seeds [0 mg/liter (ppm) K-GA3] did not germinate. When germinated at 25C (77F) the response of seeds to K-GA3 treatment was linear for both photoperiods with significantly greater total (30-day) germination occurring in the dark for seeds treated with 100, 500, or 1000 mg/liter (ppm) K-GA3. At 25C (77F), the greatest total germination (84%) was observed for seeds treated with 1000 mg/liter (ppm) K-GA3 and maintained in darkness, whereas for seeds exposed to a 16-hr photoperiod, maximum germination was 72%. At 30/20C (86/68F) the response to K-GA3 was quadratic with maximum germination at predicted rates of 882 and 875 mg/liter (ppm) KGA3 (88 and 92%, respectively) for photoperiods of 0 and 16 hr, respectively. Treatment of nonstratified seeds of seabeach amaranth with K-GA3 removed physiological (embryo) dormancy and eliminates the need for stratification (moist-prechilling). Treatment also reduced sensitivity of the seeds to light, and appeared to broaden the range of temperatures for germination.
Single Cyclanilide Applications Promote Branching of Woody Ornamentals
Authors: Holland A.S. , Keever G.J. , Kessler J.R. , Dane F.
Published: August 2020

Single applications of 0 to 200 ppm cyclanilide (CYC), an experimental bioregulator effective in stimulating lateral branching in fruit trees, were applied to the foliage of 19 species or cultivars of woody landscape shrubs over the 2004 and 2005 seasons, 12 of which exhibited increased branching in response to treatment. New shoot increases were concentration and species dependent. Compared to untreated controls at 30 days after treatment (DAT) in 2004, new shoots increased from 14 to 317% across Florida anise, ‘Elizabeth Ann’ Japanese camellia, ‘Nigra’ inkberry holly, ‘Chinsan’ azalea, ‘Red Slippers’ azalea, ‘Watchet’ azalea, ‘Ellen Huff’ oakleaf hydrangea, ‘Brandy's Temper’ sasanqua camellia, and Eleanor Taber™ Indian hawthorn following CYC application. In 2005, shoot increases at 60 DAT ranged from 32 to 240% across ‘Ellen Huff’ oakleaf hydrangea, ‘Brandy's Temper’ sasanqua camellia, Eleanor Taber™ Indian hawthorn, Olivia™ Indian hawthorn, ‘Sky Pencil’ holly, and ‘Foster’ holly. Plant size decreased, increased, or was unaffected by increasing CYC concentration. Foliage of ‘Ellen Huff’ oakleaf hydrangea in 2004 and Eleanor Taber™ and Olivia™ Indian hawthorn in 2005 was injured by CYC application, however symptoms were no longer evident by the end of the growing season. Quality of treated responsive plants at the end of the growing season in 2004, but not in 2005, was usually higher than that of untreated plants and generally increased with increasing CYC concentration.
Nodulation and Growth of Alnus nitida and Alnus maritima Inoculated with Species-specific and Nonspecific Frankia
Authors: Schrader James A. , Graves William R.
Published: August 2020

Actinorhizal plants form N2-fixing symbioses with soil-borne bacteria of the genus Frankia. Potential exists for development of sustainable, actinorhizal nursery crops that obtain most of their required N through N2 fixation, but information on host-symbiont specificity, presence of compatible Frankia in soils, and techniques to inoculate during plant production is lacking. Our objectives were to determine the effect of inoculum type and source and the effect of supplemental N on nodulation, growth, and N content of two actinorhizal species, Alnus nitida (Spach) Endl. and Alnus maritima (Marsh.) Muhl. ex Nutt. Plants of both species were subjected to one of four inoculum treatments (two crushed-nodule inocula: species-specific and cross inoculation, and two soil inocula: soil collected beneath native Alnus rubra Bong. in Washington state and native prairie soil from Iowa), were supplied fertilizer with or without N, and were grown in a greenhouse for 22 weeks. Inoculated plants nodulated, grew larger and faster, and accrued greater N content than uninoculated controls in both fertilizer treatments. Plants that received species-specific inoculum grew larger, acquired more dry weight from symbioses, and accumulated higher N content than cross-inoculated plants. Plants of A. nitida inoculated with soil from Washington state grew larger and accumulated more dry weight from symbioses than those inoculated with prairie soil, but A. maritima grew similarly with soil inoculum from both sources. Our results demonstrate that A. nitida and A. maritima can benefit from N2-fixing symbiosis during production and that potential exists for development of superior inocula and inoculation techniques.
Soil pH and Fertility Affect Growth of Leyland Cypress Christmas Trees
Authors: Hinesley L. Eric , Hardy David , Cleveland Brenda , Myers Jeana
Published: August 2020

Containerized liners of Leyland cypress [Callitropis × leylandii (syn. Cupressus leylandii, × Cupressocyparis leylandii)] were treated with two fertilizer rates [0.6 and 2.4 kg/m3 (1 lb/yd and 4 lb/yd3) of 15N–4.0P–10.0K (15N–9P2O5–12K2O) Osmocote] in Norfolk loamy sand topsoil amended with three rates of dolomitic limestone to obtain target pH values of 4.1, 5.1, and 6.1. Soil pH and fertility both affected plant growth, with negligible interaction. Averaged over both fertilizer rates, total dry weight, which increased linearly with pH, was 24 to 30% higher at the highest pH level (pH 5.9 to 6.5) than in the lowest (pH 4.7 to 4.8). After one growing season, differences among the treatment extremes (low fertility, low pH vs. high fertility, high pH) for height, shoot dry weight, root dry weight, and total dry weight were 19, 71, 44, and 64% respectively.
Drip Chemigation with Imidacloprid and Nematodes for Control of Scarab Larvae in Nursery Crops
Authors: Reding Michael E. , Zhu Heping , Derksen Richard
Published: August 2020

Larvae of scarabs, also known as white grubs, are subterranean insects that damage ornamental nursery crops when they feed on roots. Management is generally based on application of chemical insecticides to the soil surface, followed by supplemental water to leach the toxicants into the soil. Drip irrigation systems have the potential to deliver insecticides and insect pathogens to the root zones of crops to control subterranean insects. From 2004 through 2006, we tested the efficacy of imidacloprid (2004–2006), clothianidin (2006), or entomopathogenic nematodes (EPN) + imidacloprid (2005) applied through drip irrigation to control white grubs in an ornamental nursery. Insecticides (imidacloprid or clothianidin) or EPN + imidacloprid were injected into drip irrigation lines at the upstream end of rows in a commercial nursery. EPN + imidacloprid was also injected into the root zone of trees or applied as a surface drench. In 2004 and 2005, imidacloprid applied at a preventive timing through drip irrigation lines significantly reduced the numbers of white grubs in the root zones of Kousa dogwood (Cornus kousa Hance) trees. In 2006, variation in the data resulted in no significant differences at the P = 0.05 level, although, the percentage reductions of grubs by imidacloprid and clothianidin applied through drip irrigation were similar to trials in 2004 and 2005. EPN + imidacloprid applied through drip irrigation, injected into the soil, and surface drenched at a curative timing all significantly reduced the numbers of grubs compared to untreated trees. These data indicate drip irrigation is a viable delivery system for controls of white grubs in nursery crops.
Root and Shoot Growth Response of Balled-and-Burlapped and Pot-in-Pot Sugar Maple to Transplanting at Five Phenological Growth Stages
Authors: Richardson-Calfee Lisa E. , Harris J. Roger , Fanelli Jody K.
Published: August 2020

The combined effects of phenological growth stage of a tree (e.g., bud break or bud set) and production method on plant response to transplanting are not well documented. This experiment therefore examined shoot extension, trunk diameter increase, and new root length production in balled-and-burlapped (B&B) and pot-in-pot (PIP) sugar maples (Acer saccharum Marsh.) transplanted at five different phenological stages between fall 2000 and early summer 2001 (leaf drop, root quiescence, root activation, bud break, or bud set). Growth measurements were made at bud set and root quiescence in 2001 at bud set in 2002. For B&B trees, total new root length on rhizotron windows was generally greatest for trees planted at bud break and lowest for trees planted at leaf drop. Trees transplanted at leaf drop or root quiescence had the greatest trunk diameter increase, and there was no strong effect of phenological stage at planting on shoot extension. For PIP trees, evidence was weak for a phenological stage effect on post-transplant root length production and trunk diameter increase. Trees transplanted at leaf drop or bud break had the greatest shoot extension. Overall, under the well-irrigated conditions of this study, planting at bud break resulted in the most favorable transplant response for B&B trees, and PIP trees appeared to transplant with equal success at all phenological stages, including after bud set in July.
Effect of Overwintering Environment on the Survival of 30 Species of Herbaceous Perennials
Authors: Dimke K.C. , Still S.K. , Gardner D.S.
Published: August 2020

There is increased interest in overwintering containerized perennials. However, there is little information available on overwintering success. The objective of this research was to determine overwinter survival and regrowth quality of 30 perennial species hardy in USDA zones 3, 4, or 5. Three overwintering treatments were used for each species: unprotected containers outside, containers in an unheated building, or in the ground. On April 16, 2004, and May 17, 2004, following overwintering, plant quality, plant height and flowering time were evaluated. Twenty-one species were successfully overwintered in an unheated building and 13 of those had quality ratings equal to or higher than those overwintered in-ground. Ceratostigma plumbaginoides, Kniphofia Pfitzer's Hybrid, Leucanthemum ×superbum ‘Snowcap’, and Stokesia laevis ‘Honeysong Purple’ rated significantly higher when overwintered in containers stored inside than in the ground. Flowering time and height measurement differences were not significant. Coreopsis ‘Limerock Ruby’, Diascia integerrima CoralCanyon™ and Gaura lindheimeri ‘Siskiyou Pink’ did not survive in any treatment. None of the species tested, with the exception of Sedum ‘Matrona’, survived when overwintered unprotected outside. Overwintering certain species of containerized perennials inside an unheated building such as a garage is a viable option for homeowners to improve survival.
Alnus maritima ssp. oklahomensis Performance in Non-Irrigated Landscapes in the Intermountain West
Authors: Kratsch Heidi A.
Published: August 2020

Alnus maritima (Marsh.) Muhl. ex Nutt. ssp. oklahomensis Schrader & Graves has potential for ornamental use in the Intermountain West. Because this taxon is native to low-elevation wetlands, we sought to determine its response to the dry soils and climate of northern Utah. Although seeds sown directly at three non-irrigated sites in northern Utah either did not germinate or germinated and died, seeds planted in a greenhouse in soils from the three sites did germinate and survive. Hardened plants grown from these seeds and installed at the same three sites overwintered, broke bud and leafed out, but none survived longer than four weeks after bud break without irrigation. Ratings of progression of bud break were greatest (3.5 to 3.8 out of 5), and leaf scorch least (16.0 to 16.7%), in areas with either low light or wet soils. Plants from the same crop left in their containers on an irrigated gravel pad under partial shade showed no signs of stress. Our results suggest that A. maritima ssp. oklahomensis cannot survive under non-irrigated outdoor conditions in Intermountain West landscapes and may require irrigation and protection from sun and wind for optimal performance.
Production of Woody Nursery Crops in Clean Chip Residual Substrate
Authors: Boyer Cheryl R. , Gilliam Charles H. , Fain Glenn B. , Gallagher Thomas V. , Allen Torbert H. , Sibley Jeff L.
Published: August 2020

Clean chip residual (CCR) is a potential replacement for pine bark (PB) in nursery crop substrates. It is a by-product of in-field forestry harvesting practices and has been shown to produce annual plants and perennials similar in size to plants grown in PB. Studies were conducted in two locations, Auburn, AL, and Poplarville, MS, to evaluate growth of woody ornamentals grown in CCR or PB. Five species were tested; Loropetalum chinensis var. rubrum, Buddleja davidii ‘Black Knight’, Lagerstroemia indica ‘Hopi’, Lagerstroemia × fauriei ‘Natchez’, and Rhododendron indicum ‘Mrs. G.G. Gerbing’. There were few differences in plant growth indices, leaf chlorophyll content, and inflorescence number over the course of the year for all species at both sites. Percent rootball coverage was generally similar among treatments, though those grown in PB had the greatest percent rootball coverage for loropetalum and buddleja (at both sites) and azalea at Auburn. Shoot dry weight of loropetalum and crapemytrle grown in PB at Poplarville was greater than plants grown in CCR.
Response of Lotus (Nelumbo sp.) to Container Soil Volume
Authors: Tian Daike , Tilt Ken M. , Sibley Jeff L. , Dane Fenny , Woods Floyd M.
Published: August 2020

The effect of soil volume on containerized lotus (Nelumbo) production has been underreported. American lotus (Nelumbo lutea Willd.) and three cultivars (‘Embolene’, ‘98 Seed’ and ‘Karizma’) of Asian lotus (N. nucifera Gaertn.) were investigated for growth response to container soil volume in this study. Electrical conductivity, pH, plant growth indices, and plant nutritional content were influenced by container soil volume. Differences in some plant growth indices were significant between treatments with ½ and higher (½ and ¾) container height soil (CHS) in 21 or 29 liter (#5 or #7) containers. However, plant growth indices were generally not different between treatments with ½ and ¾ CHS. Lotus planted in containers with ¼ CHS usually produced the greatest plant height and underground fresh weight, while the largest number of propagules often occurred in containers with ½ or ¾ CHS. The highest number of emerging leaves was observed in plants with ¼ or ½ CHS treatments, with no significant difference in emerging leaf number between lotus grown in containers with ½ and ¾ CHS. Flower number generally decreased as soil level increased. The ¼ and ½ CHS were more efficient than ¾ CHS for lotus production in containers.
Mulch Depth Affects Weed Germination
Authors: Cochran Diana R. , Gilliam Charles H. , Eakes D. Joseph , Wehtje Glenn R. , Knight Patricia R. , Olive John
Published: August 2020

With environmental concerns increasing, non-chemical weed control in container plant production is increasing in the United States. Pine bark mini-nuggets were evaluated as a non-chemical weed control technique for two weed species; Chamaesyce maculata (L.) Small (spotted spurge) and Eclipta alba (L.) Hassk.(eclipta). On June 19, 2006, seed (25 per container) were directly placed on the potting substrate surface of #3 containers before mulching with pine bark mini-nuggets to a depth of either 0, 1.27 or 2.54 cm (0, 0.5 or 1.0 in). Additional treatments consisted of applying the mini-nugget mulch at either 1.27 or 2.54 cm (0.5 or 1.0 in) on the potting substrate then overseeding with either spotted spurge or eclipta. Eclipta number per container were 87% less 60 days after seeding (DAS) with the 1.0 in mulch depth compared to non-mulched. Furthermore, spotted spurge fresh weight (FW) was reduced by 45 and 87% (0.5 and 1.0 in, respectively) compared to the non-mulched treatment. The experiment was repeated on August 30 and spurge number per container was 90% less 60 DAS in the 1.0 inch mulch treatment compared to the non-treated containers. A third and fourth experiment also demonstrated that pine bark mini-nuggets have potential to provide non-chemical weed control in nursery crops grown in #3 containers. Results, suggest that with proper application pine bark mini-nuggets can enhance weed control in container nurseries.
In Vitro Screening of Fungicides to Control Artillery Fungi
Authors: Fidanza Michael A. , Davis Donald D.
Published: August 2020

We evaluated the influence of 26 fungicides at four different concentrations (0.1, 1.0, 10.0, and 100.0 a.i.) on in vitro growth of an artillery fungus (Sphaerobolus stellatus isolate SS8) in Petri plate culture. The most effective fungicides, as determined by comparison of mean EC50 values, were polyoxin-D and azoxystrobin, followed by pyraclostrobin, triademifon, tebuconazole, propiconazole, thiophante-methyl, triticonazole, thiram, and fludioxonil. These in vitro laboratory findings need to be evaluated in the field before specific fungicides can be recommended to control artillery fungi in landscape mulch.
NAA is More Effective Than IBA for Rooting Stem Cuttings of Two Nyssa spp.
Authors: Boyer Nickolee Z. , Graves William R.
Published: August 2020

We conducted two experiments to determine whether Nyssa aquatica and Nyssa ogeche could be propagated from softwood cuttings. In the first experiment, two commercial auxin formulations were used, each at two concentrations. In the second study, we compared root formation among cuttings treated with 3000-ppm indole-3-butyric acid (IBA) in liquid or talc, 3000-ppm 1-naphthaleneacetic acid (NAA) in liquid, and a combination of 1500-ppm IBA and 1500-ppm NAA in liquid. Cuttings were taken from terminal and subterminal positions on juvenile stock plants and held under intermittent mist for six weeks. More terminal cuttings rooted than did subterminal cuttings. A liquid formulation of NAA or NAA and IBA was more effective than IBA at promoting root formation for both species. Up to 93% of cuttings rooted when treated with a solution containing NAA and IBA. Cuttings of N. aquatica treated with NAA in solution produced up to eight times more roots than cuttings treated with no auxin or IBA. For both species, three times more cuttings rooted when treated with IBA in liquid compared to IBA in powder. Results indicate N. aquatica and N. ogeche can be propagated from softwood cuttings, and rooting is enhanced by treating terminal cuttings with NAA in solution.
Influence of Pure Mulches on Survival, Growth and Vitality of Containerized and Field Planted Trees
Authors: Percival G.C. , Gklavakis Evangelos , Noviss Kelly
Published: August 2020

Mulching as a means of reducing soil moisture stress, suppressing weed growth and improving soil fertility is widely recognised throughout the arboricultural, nursery and landscape industry. The influence of a pure mulch, i.e. mulch derived solely from one tree species, has received little study. The purpose of this research was to evaluate pure mulches derived from European beech (Fagus sylvatica L.), common hawthorn (Crataegus monogyna JACQ), silver birch (Betula pendula ROTH.), common cherry (Prunus avium L.), evergreen oak (Quercus ilex L.) and English oak (Q. robur L.) on survival and growth of two commonly planted urban trees (European beech, common hawthorn) following containerization and two economically important fruit trees (apple (Malus cv. Gala), pear (Pyrus communis ‘Concorde’) following field transplanting. In the case of beech, a highly sensitive transplant species, survival rates were increased from 10 to 70% following containerization. In the case of hawthorn, a transplant tolerant species, no difference in survival rates between mulched and non-mulched controls were recorded, however, marked differences in growth between, and compared to, non-mulched control trees existed. In field planted apple and pear trees crown volume and fruit yield could be increased by 53 and 100%, respectively, by application of an appropriate pure mulch. Allelochemical testing of water soluble extracts of each pure mulch indicated positive benefits in terms of enhanced seed germination and seedling relative growth rates with one exception — a mulch derived from beech where no positive benefits were found. In conclusion, pure mulches offer positive benefits for those involved in the care and maintenance of urban trees as well as nursery, forestry, orchard and horticultural crop production. Pure mulches require no capital investment and only small adjustments to standard management aftercare procedures.
Desiccation Tolerance of Green Ash and Sugar Maple Fine Roots
Authors: Watson Gary W.
Published: August 2020

Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.
Root Ball Shaving Improves Root Systems on Seven Tree Species in Containers
Authors: Gilman Edward F. , Paz Maria , Harchick Chris
Published: August 2020

Established forest trees planted from small containers are less stable at the point where roots fork, bend or branch as a result of deflection by container wall, but less is known about the post-transplant impact of root deflections resulting from growing trees in large containers. We either root pruned by shaving off the periphery of the #3 container root ball as it was planted into the #15 container or did not root prune on 5 tropical and 2 temperate tree species. Shaving did not affect trunk caliper or tree height on the seven species tested under the conditions of this study. Shaving removed the entire outer and bottom 2.5 cm (1 in) of the root ball and reduced or eliminated culls on five of seven species. The largest diameter roots on trees in #15 containers that were not root pruned when shifted from #3 containers were kinked, descended down the container wall, or circled at the position of the #3 container. These root defects were largely missing on trees with root balls that were shaved of peripheral roots when shifted into #15 containers. The largest roots on shaved trees grew more-or-less straight radially from the trunk. Shaving the root ball periphery and bottom is recommended to improve root ball quality by reducing root ball defects.
Herbicide Efficacy in Alternative Substrates for Container-grown Nursery Crops
Authors: Cochran Diana R. , Gilliam Charles H. , Wehtje Glenn , Fain Glenn B. , Wright Robert D. , Boyer Cheryl R.
Published: August 2020

Three experiments were conducted to evaluate the influence of alternative substrates on herbicide efficacy in container grown nursery crops. In Experiment 1, alternative substrates evaluated were either pine wood chips hammer-milled, to pass between 0.48 cm (0.19 in) screen (PWCH1) or 0.64 cm (0.25 in) screen (PWCH2), whole pine trees chipped or hammer-milled (WTCH), to pass between a 0.48 cm (0.19 in) screen, or the previously mentioned combined with pinebark. A commercial pine bark substrate (PB) with a 6: 1 (by vol) ratio of pine bark to sand was maintained as a control treatment. Rout® at 3 lbs aia (oxyfluorfen + oryzalin at 2.24 + 1.12 kg·ha−1) and Ronstar at 4.0 lb aia (oxadiazon at 4.48 kg·ha−1) were applied at recommended label rates. Herbicides were applied and irrigated, and each container was overseeded with 25 spotted spurge (Euphorbia maculata) seed per container. In general, the greatest spurge numbers occurred in PB substrates. Rout provided superior spurge control compared to Ronstar. In Experiment 2, substrates evaluated were PWCH2, WTCH and PBS with 7.0 kgm−3 (12 lbsyd−3) of Polyon 17-6-12 or with an additional 8 lbs·yd−3 of Polyon 17-6-12, or PWCH2 and WTCH combined with composted poultry litter (CPL). PWCH2 tended to have the fewest spurge numbers throughout the experiment, while WTCH and PBS tended to have similar spurge numbers and spurge fresh weight. Addition of CPL and additional fertilizer tended to increase spurge numbers and spurge fresh weight in all substrates. Rout and Ronstar provided similar spurge control in this study. In Experiment 3, substrates evaluated were PB (100%), WTCH (100%), CCR (100%), and PB: S (6: 1 vol), WTCH: S (6: 1 vol), and CCR: S (6: 1 vol). Rout and Ronstar were each applied at 0.25×, 0.50×, 075×, and 1.0× label rate. There was a significant substrate affect on all dates except 14 DAT. Spurge numbers and spurge fresh weight were greatest in PB or PB: S substrates. Spurge numbers and spurge fresh weight in general decreased with increasing herbicide rates. At 45 DAT and 60 DAT, Rout had superior spurge control compared to Ronstar. With WT and CCR substrates, Rout provided excellent control (less than 1.0 gram fresh weight) at the 0.50× and 1.0× rates. In general, weed control in alternative substrates was superior to that obtained in commercially used pinebark.
Dormancy and Germination In Vitro Response of Hydrangea macrophylla and Hydrangea paniculata Seed to Light, Cold-Treatment and Gibberellic Acid
Authors: Greer Stephen P. , Rinehart Timothy A.
Published: August 2020

Seed germination was optimized for ten Hydrangea macrophylla (Thunb.) Ser. and two Hydrangea paniculata Siebold cultivars in vitro. Methods were also developed to assay seed physiology. Best results for in vitro study were obtained with 0.5× Gamborgs solid media in conjunction with Plant Preservative Mixture (PPM), and by sterilizing seed with trichloro-s-triazinetrione (Trichlor). Assays of physiology were conducted by sterilizing seed and treating with combinations of white and red light, cold-treatment, gibberellic acid and potassium nitrate, and light cycles. Estimates of seed viability/dormancy, germination of non-dormant seed, and germination overall were calculated for each treatment combination. The most favorable conditions for overall Hydrangea seed germination were cold-treatment for 6 weeks, imbibition with GA3 + KNO3, and plating on half-strength Gamborgs media supplemented with GA3 in the presence of white light.
Spent Tea Grinds as a Substrate Component in Nursery Crop Production
Authors: Wells Daniel E. , Sibley Jeff L. , Gilliam Charles H. , Dozier William A.
Published: August 2020

In the United States commercial, ready-to-drink tea production has increased dramatically during the past 20 years, leading to an increased amount of waste. Spent tea grinds (STG) is the finely ground waste product of the tea brewing process that possesses some physical properties similar to peat moss (PM), making it a potential replacement for common substrate components such as pine bark (PB) and PM. ‘Tuscarora’ crapemyrtle (Lagerstroemia indica L. ‘Tuscarora’), ‘Chang's Ruby’ loropetalum (Loropetalum chinense Oliv. ‘Chang's Ruby’), ‘Fire Power’ nandina (Nandina domestica Thunb. ‘Fire Power’), and ‘Macrantha Pink’ azalea (Rhododendron indicum L. and Sweet ‘Macrantha Pink’) were grown in containers filled with five substrates composed of PB, STG, or a combination thereof. Substrate pH remained within an acceptable range throughout the study. Substrate electrical conductivity (EC) values were within an acceptable range at the beginning of the study, but fell below an acceptable range in substrates containing 50% or greater (by vol) STG by the end of the study. For all four species, plant growth in substrates containing up to 50% by volume STG was similar to those grown in 100% PB. Estimated leaf chlorophyll content (SPAD) of crapemyrtle, loropetalum, and azalea was the same for all treatments at the end of the experimental period.
Effects of Flooding on Physiology and Growth of Four Woody Ornamental Species in Marl Soil of South Florida
Authors: Martin Cliff G. , Schaffer Bruce , Mannion Catharine
Published: August 2020

In south Florida nurseries, trees are often grown in marl soil, which is heavy, clay-like, calcareous soil that is slow to drain and prone to periodic flooding during the rainy season. Green buttonwood, mahogany, pond apple and Surinam cherry are grown in this soil. We tested effects of flooding on leaf gas exchange and growth of these four species to determine their flood tolerances in marl soil. Green buttonwood, mahogany, and Surinam cherry each had consistently lower leaf gas exchange and plant growth in flooded than in non-flooded marl soil, which suggests low tolerance to flooding. In contrast, flooding had little or no effect on leaf gas exchange and growth of pond apple, indicating that this species was tolerant of flooding in marl soil. Green buttonwood and pond apple had larger stem diameters and more hypertrophic stem lenticels when flooded than when not flooded. Flooded green buttonwood also developed adventitious roots. Pond apple appears to be a good choice for planting in low-lying areas in marl soil typical of outdoor nurseries in south Florida. In contrast, care should be taken to avoid planting green buttonwood, mahogany, and Surinam cherry in marl soil in flood-prone areas.
Effects of s-ABA on the Physiology and Marketability of Various Container-Grown Taxa During Short-Term Desiccation
Authors: Hebert Cary J. , LeBude Anthony V. , Campbell Craig
Published: August 2020

Reduced post harvest care of woody plant material in mass retail settings can decrease the number of days plants remain marketable. If plants are sold on consignment for growers, reduced sales can lead to poor profitability. This study investigated the effect of spray applications of s-abscisic acid (s-ABA) (ConTego™ Pro SL, Valent Biosciences Corp.) to increase the number of days of marketability for various woody taxa in a simulated retail setting. In the first stage of the study, various well-watered container-grown taxa were treated with a spray application of either 0, 1000 or 2000 mg·liter−1 of s-ABA and water was withheld. Daily, desiccation symptoms were recorded to determine if plants had reached the critical wilting point (CWP) and thus became unmarketable. Marketability was increased approximately 1–7 days for plants treated with 2000 mg·liter−1 of s-ABA compared to nontreated plants. In the second stage, marketability and physiology of Ligustrum japonicum ‘Recurvifolium’ (wavy leaf privet) were monitored after plants were treated with spray applications of 0, 500, 1000, 1500 or 2000 mg·liter−1 of s-ABA and water withheld. Stomatal conductance (gs) declined for all plants depending on the concentration applied. Plants treated with s-ABA had lower gs rates and remained marketable longer than nontreated plants. All plants fully recovered to pretreatment gs rates provided they were rewatered immediately upon reaching the CWP. Spray applications of s-ABA can increase shelf life of select woody ornamentals.
Sales, Trade Flows and Marketing Practices within the U.S. Nursery Industry
Authors: Hall Charles R. , Hodges Alan W. , Palma Marco A.
Published: August 2020

This article provides an overview of marketing and production practices of the U.S. nursery and greenhouse industry in 2008, based on information collected through the 2009 National Nursery Survey, the fifth such survey since 1988. Lists of nursery firms for each state were assembled from the respective Department of Agriculture (Plant Health Board) offices responsible for licensing nursery producers. The compiled state lists resulted in a combined listing of 38,000 certified nursery operations. A total of 3,044 usable questionnaires were returned from a sample of 17,019 firms for an effective 17.9 % response rate. The survey was administered through both mail and internet questionnaires, with repeated contacts attempted, and a follow-up telephone survey on non-respondents. Survey respondents reported total annual sales of $4.45 billion in 2008, or an average of $1.73 million per firm, and total employment of 48,833 permanent and temporary jobs. Based on an adjusted population of validated active firms (19,803), total U.S. nursery industry sales were estimated at $27.14 billion, and total employment was estimated at 262,941 jobs. The highest sales and employment were in the Pacific and Southeast regions, led by the states of California and Florida. Overall, 77 percent of sales were made through wholesale outlets including landscape firms, single-location garden centers, and re-wholesalers.
Early Postemergence Control of Spotted Spurge in Container Production
Authors: Christopher Marble S. , Gilliam Charles H. , Wehtje Glenn R. , Hoogmoed Albert J. Van , Palmer Cristi
Published: August 2020

Four experiments were conducted to evaluate early postemergence control of spotted spurge (Chamaesyce maculata) in nursery crops using preemergence active herbicides. In Experiment 1, spotted spurge (SS) seed were overseeded at two different dates in a commercial pine bark substrate and were grown until reaching either the cotyledon to one leaf (C–1L) stage, or the two to four leaf (2–4L) stage. Herbicides applied included: Broadstar 1604 (flumioxazin), V-10142 (imazosulfuron), and Tower (dimethenamid-P). These products were applied postemergence at their respective recommended label rate (1 ×) and twice (2 ×) this rate to SS either at the C–1L stage or at the 2–4L stage. In general, V10142 and Tower provided the greatest injury to SS in the C–1L. Tower also provided greatest SS injury in the 2–4L stage. In Experiment 2, postemergence control was tested in the C1-L and 2–4L stages with Broadstar 1604, FreeHand (dimethenamid-P 0.75% + pendimethalin 1.0%), Tower, and Pendulum 3.3 EC (pendimethalin) at the 1× and 2× the label rate. FreeHand at 2×, along with Tower and Pendulum at both rates provided the highest SS injury ratings in the C–1L. Tower at 2× and Pendulum at both rates provided greatest SS injury in the 2–4L. In Experiments 3 and 4, Broadstar (1/2×, 1×, and 2× rate), Casoron (dichlobenil) (1× and 2×), HGH-63 (oxyflurfen) (1×), Certainty (sulfosulfuron) (1× and 2×), Tower (2/3× and 1×), V-10142 (1× and 2×), Pendulum 3.3 EC (1× and 2×), FreeHand (1× and 2×) were applied to SS in either C–1L or 2–4L as described above. Results from Experiments 3 and 4 indicate that Certainty (both rates), Tower (both rates), Pendulum (both rates), and FreeHand (both rates) have postemergence activity on immature SS, especially when applied in the C–1L stage. Postemergence activity declined when herbicides were applied to SS in the 2–4L, however Pendulum (both rates), Certainty (both rates), and FreeHand (2× rate) had a marginal effect.
Comparison of Aged and Fresh WholeTree as a Substrate Component for Production of Greenhouse-Grown Annuals
Authors: Gaches Whitney G. , Fain Glenn B. , Eakes Donald J. , Gilliam Charles H. , Sibley Jeff L.
Published: August 2020

WholeTree (WT) is a potential renewable greenhouse substrate component created by chipping and milling all aboveground portions of a pine tree (Pinus taeda L.). While research regarding the viability of WT as an alternative substrate component is widely available to growers, the potential benefits of aging WT remain unclear. The growth of Dreams White petunia (Petunia ×hybrida ‘Dreams White’) and Little Hero Yellow marigold (Tagetes patula ‘Little Hero Yellow’) in 1:1 (by vol) fresh WT:peat (FWTP) and 1:1 (by vol) aged WT:peat (AWTP), as well as physical properties of AWTP and FWTP were evaluated. For Experiment 1, AWTP had 17.6% particles greater than 3.2 mm as opposed to 12.4% for FWTP. In Experiment 2, this trend was reversed with 8.1% of AWTP particles greater than 3.2 mm and 20.4% for FWTP. For Experiment 1, AWTP had 90.5% total porosity (TP) as compared to 94.4% with FWTP. Air Space (AS) for AWTP was less than FWTP; AWTP had 10% more container capacity (CC) than FWTP. Bulk Density (BD) was similar in Experiment 1. There was no difference in TP in Experiment 2; however, all other physical properties followed a similar trend to Experiment 1. In both experiments marigolds grown in AWTP generally had a lower leachate pH and a higher EC than those grown in FWTP; a trend which was similar in petunia although differences were not present throughout the entire study. Marigolds grown in AWTP had 33% more blooms and 44% greater dry weight than those grown in FWTP, a trend similar in petunias. Aged WT in this study provided a more suitable substrate component for greenhouse grown marigolds and petunias than fresh WT.
Survival and Growth of Callicarpa americana (American Beautyberry) of Northern and Southern Origin in USDA Hardiness Zones 5 and 6
Authors: Graves William R. , Thomas Andrew L.
Published: August 2020

Our objective was to determine whether provenance of origin and use of organic mulch influence survival, vegetative growth, and the number and size of fruit of Callicarpa americana L. (American beautyberry) planted north of its natural distribution in the central United States. Forty-eight plants were established in 2006 at each of four locations north of the natural distribution, two in Missouri and two in Iowa, and at one location within the natural distribution in Arkansas. Plants at each location (24 per provenance) were propagated from seeds collected from plants indigenous to southern Missouri and central Florida. Use of organic mulch increased percentage survival at two of four sites north of the natural distribution after Winter 2006–2007 and across all four northern locations after Winter 2007–2008. Survival of plants from the two origins was similar after Winter 2007–2008. Plants from Florida grew taller than plants from Missouri at the two planting locations in Missouri during the 2007 growing season. Development of fruit was poor in Iowa and was greatest on plants from Florida installed in southern Missouri and on plants from Missouri installed in central Missouri. Survival after Winter 2007–2008 was reduced to an average of 47% at the two sites in Iowa, and, across all sites, more plants from Missouri survived than plants from Florida. Plants within the natural distribution in Arkansas were 68% taller and had clusters of fruit 31% larger in late 2008 than plants at the closest site north of the natural distribution. We conclude American beautyberry can survive when planted in areas with winters colder than those where the species occurs naturally, and that plants from a northern provenance (Missouri) possess a greater capacity to survive than plants from Florida when planted north of the natural distribution in the Upper Midwest. Although the genetic potential for growth and displays of fruit is not manifest north of the species' natural limit, American beautyberry can be an attractive addition to landscapes in United States Department of Agriculture (USDA) hardiness zones as cold as zone 5b, where plants from a northern origin that are mulched during winter should be used.
Barricade (prodiamine) Persistance in Pinebark:Sand Substrate
Authors: Briggs Jeanne A. , Whitwell Ted , Riley Melissa B.
Published: August 2020

Barricade (prodiamine) herbicide is used for preemergence weed control in container-grown plants and has been shown to injure certain landscape plants. This research investigated Barricade's (prodiamne's) persistence and movement in a pine bark:sand substrate with greenhouse grown azaleas treated with Barricade (prodiamine). A bentgrass bioassay study indicated similar Barricade (prodiamine) distribution throughout the containers through 60 days after application (DAA). Barricade (prodiamine) residues extracted from the substrate were similar within specific horizons at 30 and 60 DAA indicating a downward herbicide migration within the container. Barricade (prodiamine) may be adsorbed to fine substrate particles and move in the container with the displacement of fine particles during irrigation and substrate settling.
Canna spp. Cultivar Response to the Lesser Canna Leafroller, Geshna cannalis (Quaintance), and the Japanese Beetle, Popillia japonica (Newman)
Authors: Kristine Braman S. , Carr Evelyn R. , Quick James C.
Published: August 2020

Twenty-two cultivars of canna lilies, Canna × generalis, were evaluated for potential resistance to the lesser canna lily leafroller, Geshna cannalis, and the Japanese beetle, Popillia japonica. Both of these pests cause defoliation of the plants resulting in reduced plant fitness and aesthetic injury. Cultivars sustaining the most damage by leafrollers were ‘Richard Wallace’, ‘Firebird’, and ‘Black Knight’. While Japanese beetle injury varied, cultivars most consistently damaged by beetles were ‘Lenape’, ‘Scarlet Wave’, ‘Dawn Pink’, and ‘Crimson Beauty’. While all plants sustained at least some injury, cultivars that consistently had the least amount of damage by leafrollers were ‘Maudie Malcolm’, ‘Striped Beauty’, and ‘Journey's End’. ‘Maudie Malcolm’ and ‘Striped Beauty’ were similarly avoided by Japanese beetles, while ‘Journey's End’ sustained moderate injury from this pest. Tall cultivars with red or orange flowers and some red in their foliage were especially vulnerable to infestation by the lesser canna leafroller.
Economic, Environmental, and Health/Well-Being Benefits Associated with Green Industry Products and Services: A Review
Authors: Hall Charles R. , Dickson Madeline W.
Published: August 2020

Green industry firms have competed for decades on the basis of quality and service. While these competitive dimensions are still important, the industry has continued along its path of maturation and firms must incorporate other factors into their value proposition in order to be successful in this hypercompetitive market. Given the recent economic downturn of 2008–2009, consumers are more value-conscious than ever, but are still willing to consume, and pay premiums for, products and services that enhance their quality of life. This paper summarizes the peer-reviewed research regarding the economic benefits, environmental benefits (eco-systems services), and health/well-being benefits of green industry products and services that serve to enhance the quality of life for consumers.
Use of Ground Miscanthus Straw in Container Nursery Substrates
Authors: Altland James E. , Locke James C.
Published: August 2020

Pine bark (PB) is the primary component in nursery substrates in the United States. Availability of pine bark is decreasing and price is increasing. The objective of this research was to determine if miscanthus straw (MS) can replace all or part of the pine bark fraction in nursery container substrates. Five substrates were created that contained 15% sphagnum peatmoss, 5% municipal solid waste compost, and the remaining 80% consisted of one of the five following PB:MS ratios: 0:80, 20:60, 40:40, 60:20, and 80:0. Luna Red hibiscus (Hibiscus moscheutos) were grown in each substrate and evaluated for eight weeks in a greenhouse. Ground MS increased air space and decreased container capacity and bulk density as its concentration in the substrate increased. Additions of MS did not affect hibiscus chlorophyll content, and had negligible effects on hibiscus foliar nutrient levels. Increasing levels of MS caused a decrease in plant shoot dry weight, although growth reduction was most pronounced with 80% MS. Ground MS has potential to be a suitable substrate for nursery growers, however, some changes to management practices will be necessary.
Influence of Plant Age on Cold Hardiness of Three Container-Grown Herbaceous Perennials
Authors: Kingsley-Richards S.L. , Perry L.P.
Published: August 2020

Overwintering container-grown perennial plants is often necessary during their production. Rooted vegetative cuttings potted at the beginning of the growing season and rooted vegetative cuttings potted at the beginning of the previous growing season, were exposed to−2,−5,−8,−11, and−14C (28, 23, 18, 12, 7F) in January then returned to a greenhouse kept at 3 to 5C (37 to 41F). In June, plants were assessed using a visual rating scale (1 = dead, 3–5 = increasing salable quality) and dry weight of foliage regrowth. For Geranium × cantabrigiense ‘Karmina’, studied for one year, age did not affect either rating or dry weight. For Sedum ‘Matrona’, studied for two years, age had no effect on dry weight but ratings were higher for two-year-old plants than one-year-old plants in the first year and higher for one-year-old plants than two-year-old plants in the second year. For Leucanthemum × superbum ‘Becky’, studied for two years, age affected both rating and dry weight, which were higher for one-year-old plants. Of the cultivars studied, overwintering one-year-old, container-grown plants resulted in more growth and higher quality than overwintered two-year-old plants.