Annual/Termination Reports:

[06/22/2005] [04/19/2006] [10/12/2007] [11/05/2008]

Report Information

Participants

Altland, James (james.altland@oregonstate.edu) - Oregon State University, NWREC;
Boyer, Charles (charles.boyer@oregonstate.edu) - Oregon State University (Administrator);
Cameron, Art (cameron@msu.edu) - Michigan State University (Chairman);
Graves, Bill (graves@iastate.edu) - Iowa State University;
Harris, Roger (rharris@vt.edu) - Virginia Polytechnic Institute;
Hensley, David (dhensley@uark.edu) - University of Arkansas;
Klett, Jim (Jim.Klett@colostate.edu) - Colorado State University;
Maynard, Brian (bmaynard@uri.edu) - University of Rhode Island (Vice Chairman and Secretary);
Sellmer, Jim (jcs32@psu.edu) - Pennsylvania State University;
Neal, Cathy (cathy.neal@unh.edu) - University of New Hampshire;
Pemberton, Brent (b-pemberton@tamu.edu) - Texas A&M University;
Sharma, Jyotsna (jsharma@ufl.edu) - University of Florida;
Starbuck, Chris (starbuckc@missouri.edu) - University of Missouri;
Tripepi, Bob (btripepi@uidaho.edu) - University of Idaho;
Guests: Bob Aube (Morningstar Nurseries, Inc., Rhode Island), Mark Lurie and Arden Lurie (M&L Irrigation, Inc., South Carolina), Randy Mayer, Jim Robbins (UArk), Robert Wright (VPI).

Brief Summary of Minutes

Accomplishments

The research and Extension programs of WERA-058 participants span nursery crop topics from new plant material to production through post-harvest handling to efficient management of landscapes.<br /> <br /> Researchers in Pennsylvania have identified trees which are not hosts of Anoplophora glabripennis (Asian longhorned beetle, ALB) and on which the adults, eggs, and implanted larvae die while ingesting wood from the trees. In addition, they have evaluated two species, Acer platanoides and Viburnum opulus, for seed production, viability, and germination rate among cultivars as part of evaluating differences in their potential to become invasive. Researchers in Iowa have generated new information on the potential of Rhamnus caroliniana as a shrub or small tree for managed landscapes, including data on its potential as a host for soybean aphid. they also have obtained new information on the genetic relatedness and propagation of the three species of Dirca (leatherwoods) and studied the ecology and genetics of Dirca occidentalis<br /> <br /> Rhode Island continues to evaluate the growth and marketing requirements of new, sustainable plant species for introduction to the nursery industry. More than 75 trees and shrubs were accessioned in 2004. A collaboration with the URI Master Gardener Program using volunteers and undergraduate students to assessing plant performance has been suspended due to time constraints for the PI. Propagules of all plant materials are made available to cooperating nurseries and arboreta, and to the public on a limited basis. A new research program on the use of low-input plants for roadside planters was started in 2004. Thirty-eight taxa of succulents have been accessioned and grown in replicated mesocosms to investigate suitable growing media and cold hardiness. Rhode Island has continued to research the control of deer in nursery and landscape settings, with the goal of improving plant production and maintenance. Major initiatives include inventories of species preferences for deer rubbing damage in northeast nurseries, and economic impacts of deer damage in the green industry.<br /> <br /> Several stations are evaluating hardiness, resistance and disease management. Research in Oklahoma is developing methods for controlling anthracnose caused by Colletotrichum gloeosporioides on Euonymus fortunei was continued in the 2004 growing season. Results showed that application of mancozeb continued to reduce anthracnose symptoms, but mancozeb did not eliminate symptoms. Copper sulfate pentahydrate did not reduce anthracnose symptoms. Plants grown with black plastic under containers had slightly fewer symptoms than those grown on gravel, but the difference was not horticulturally significant. Periodic application of 10% bleach solution to the surface of plastic or gravel did not decrease anthracnose symptoms.<br /> <br /> Pennsylvania has generated new information on the hardiness and arthropod susceptibility of western and asian Tsuga species during evaluation at five climatic and environmentally diverse sites over USDA Hardiness Zones 5 and 6. An Oklahoma study was initiated to evaluate plant growth and winter survival of trees grown above ground in fabric containers compared to those grown in plastic containers. Soil temperatures in the containers were collected at 30-minute intervals throughout the study to determine whether container type affected root zone temperatures. The data are currently being analyzed from this study. Research at Iowa has determined impacts of nitrogen fertilization, root-zone heat, and root-zone oxygen on the formation, development, and function of N2-fixing root nodules on Alnus maritima.<br /> <br /> New Mexico researchers tested the tolerance to drought and salinity of bigtooth maple (Acer grandidentatum) seedlings from the Intermountain West and Southwest regions to find a plant better suited for southern New Mexico's harsh growing conditions. The Guadalupe Mountains in Texas, the Lost Maples State Park in Texas, and Dripping Springs State Park in New Mexico were identified as provenances that could be used as locations for selecting bigtooth maples for arid environments. Several promising specimens have been selected. The drought responses and water use of Mexican elder (Sambucus mexicana) was evaluated. Mexican elder is a landscape plant that is commonly used in landscapes of the Southwestern United States. Drought-deciduousness is a major drought-adaptation mechanism for Mexican elders.<br /> <br /> Oklahoma and Ohio researchers are conducting a study with other researchers across the U.S. determining transpiration rates of trees grown in 15-gallon containers. This study was a preliminary study to subsequent research currently in progress that is evaluating plant nutrient use of trees grown in containers using different low pressure drip systems. Research at Rhode Island included the continued development of a 30x100 computer-controlled microirrigation system with 12 independent irrigation zones. All irrigation water applied in this system is recaptured and allows for water quality analysis. This facility is being used to evaluate irrigation methods and container media to optimize low-water use container culture in the northeast.<br /> <br /> During 2002 and 2003, a cooperative research project was initiated between Texas A&M and the University of Arizona. The project is still in progress and involves a determination of the effects of digging date, cold storage, and cultivar selection on containerized forcing of bare-root garden rose plants. Each year, several million rose plants are harvested bare-root from fields in Arizona and shipped to Texas where they are containerized and grown to bud and bloom for garden center sales across North America. Financial support has been received by nurseries in both locations, and the project was facilitated by participation of scientist from the two university in WERA-058.<br /> <br /> New Mexico researchers have successfully micropropagated bigtooth maples from greenhouse-grown, two-year seedlings. Tissue culture lines have been established that will be used for further testing. Tissue-cultured material will be distributed to nurseries for propagation and production.<br /> <br /> Researchers in Missouri and Idaho continue to investigate the use of the Missouri Gravel Bed (MGB). The MGB is a method for handling trees and shrubs that allows bare root plants to be planted throughout the year with excellent survival. In the MGB system, dormant, bare root plants are placed with their roots in frequently-irrigated river rock, containing 10% masonry sand and allowed to develop roots in the rock. MGB was evaluated in MO as a method for preparing planting stock to be grown in containers. Nyssa sylvatica (black gum) and Syringa patula Miss Kim (lilac) plants were evaluated. At the end of the field growing season, root systems of Syringa and Nyssa plants grown in the gravel for a one year prior to potting into 7-liter pots were as large or larger than those grown using the conventional method of potted in smaller pots and overwintered under plastic film covering prior to shifting up to the larger container. Plants that had been fall potted and overwintered in the field in the pot-in-pot nursery were also larger than fall potted plants overwintered under a conventional covering of polyethylene film and 8 mm thick foam blanket. <br /> <br /> In Idaho corkbark fir and pinyon pine trees seedlings grown in the MGB had larger root systems than those grown in field soil. Although shoot diameters and stem heights were similar for fir or pine seedlings in the gravel bed and field soil, root volumes and dry weights were higher for gravel bed-grown plants than those grown in the field. Pinyon pine seedlings grown in the gravel bed produced at least 37% more root dry weight and 86% more root volume than seedlings grown in field soil. In addition, only about 12% of the pinyon pine seedlings survived when transplanted into the soil, but about 25% of those transplanted into the gravel bed survived.<br /> <br /> Spruce trees that had all the soil removed from their root systems survived as bareroot trees in pea gravel and basalt gravel. Root systems on all trees regenerated many new fibrous roots. Roots on some of the trees were extensively colonized by mycorrhizae. All trees grew about 8 cm in height despite severe soil loss from their roots. The main leader on about half of the trees died back about 10 cm. Overall, however, the trees survived well. All trees lifted from the gravel beds in September and October survived transplanting to the field (ID). <br />

Publications

Impact Statements

1. Pennsylvania research has provided growers and landscapers with a list of landscape trees that are not susceptible to Asian longhorned beetle (ALB) infestation. Municipal arborists, private arborists, and federal agencies now have data on ALB to assist in quarantine monitoring in infested sites and to allow inspection in vulnerable sites near warehouses and shipping facilities.
2. Iowa research has led to the distribution of new selection of Alnus maritima subsp. oklahomensis (September Sun). In addition, the protocols have been developed for propagation of Dirca spp, a new landscape plant. The research on the ecology and genetics of Dirca occidentalis is influencing strategies for conserving populations within preserves and open-space-district lands in California.
3. Oklahoma research on anthracnose provides the nursery industry with recommendations for managing this disease. One Oklahoma nursery has adopted these practices and eliminated their fungicide program except for spot spraying when necessary. This nursery has estimated that they reduced their pesticide application costs by about $45,000 in 2004.
4. Research at Rhode Island on irrigation practices and modified container media requirements will increase production potential and reduce production costs by 10-30%. Research on plant growth and marketing will boost industry sales and increase production potential by identifying plants that will stimulate consumer interest and increase purchasing. Research on reducing damage by deer in nurseries and landscapes should have an immediate impact of $3,000 to $15,000 per nursery.
5. Several studies in Texas and Arizona have helped determine the best digging date, cold storage, and cultivar selection combination to ensure successful containerized forcing of garden rose plants. In addition, an effect of the field environment on subsequent growth in containers was discovered.
6. A study in Arizona addressed the problem of moisture loss during harvest, shipping, and handling of bare-root roses, and critical moisture contents for several cultivars was determined. These moisture contents provide tools for the best handling of rose plants.
7. Studies in Missouri and Idaho confirmed that the Missouri Gravel Bed can facilitiate the handling and establishment of trees and shrubs. Using MGB, one can avoid the costs of pots, container growing medium and labor associated with growing in the smaller containers prior to potting in the final container. Overwintering plants in a gravel bed eliminates costs associated with conventional winter protection and provides plants with superior root systems.
8. Scientists at Texas Tech University, the University of Florida and Utah State University have investigated water use of shade trees. These studies are providing tools for optimal utilization of water in urban landsapes. Researchers at Utah State University are collaborating with cities in the Salt Lake City metropolitan region to maximize irrigated landscape water savings.

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Report Information

Participants

Altland, James (james.altland@oregonstate.edu) - Oregon State University (Sub for Richard Regan);
Boyer, Charles (charles.boyer@oregonstate.edu) - Oregon State University (Administrator);
Cameron, Art (cameron@msu.edu)- Michigan State University;
Graves, Bill (graves@iastate.edu) - Iowa State University;
Maynard, Brian (bmaynard@uri.edu) - University of Rhode Island (Chair, Secretary);
Mickelbart, Mike (mickelbart@purdue.edu) - Purdue University;
Sellmer, Jim (jcs32@psu.edu) - Pennsylvania State University;
Sharma, Jyotsna (jsharma@ufl.edu)- University of Florida (Vice-Chair & Host);
St. Hilaire, Rolston (rsthilai@nmsu.edu) - New Mexico State University;
Starbuck, Chris (starbuckc@missouri.edu) - University of Missouri;
Stewart, Ryan (rstewart@uiuc.edu) - University of Illinois (Sub for Gary Kling);
Guests: Jeff Norcini, IFAS NFREC; Gary Knox, IFAS NFREC; Mary Starbuck, Missouri

Brief Summary of Minutes

Accomplishments

Researchers at the New Mexico State University have determined the salinity responses of bigtooth maple (Acer grandidentatum) seedlings from New Mexico, Utah, and Texas. Plants from the Guadalupe Mountains in Texas were identified as being salt tolerant. The preliminary phylogenetic relationships of bigtooth maples from provenances in Utah, New Mexico, and Texas have been determined. The universality of tissue culture protocols for micropropagating bigtooth maples have been tested an successful protocols developed.<br /> <br /> New Mexico State University researchers have determined residential homeowner preferences for managed landscapes.<br /> <br /> Research at Oklahoma State University was initiated testing anthracnose incidence on containerized Euonymus fortunei grown on black plastic or gravel with periodic bleach applications to the test surfaces. Research testing above-ground production of red maple, sweetgum, and live oak trees in fabric vs. plastic containers was completed. Data are currently being analyzed from these studies.<br /> <br /> The major emphasis in research at the University of Missouri in 2005 was on improving the effectiveness of the Missouri Gravel Bed as a method for facilitating the establishment of trees and shrubs. Previous work showed that incorporation of calcined (kiln-fired) clay into pea gravel improved the root and shoot growth of Gymnocladus dioicus seedlings grown in a gravel medium. The objectives of current work are to determine the optimum amount of calcined clay to incorporate and to evaluate its effects on physical properties of the rock/clay mixture.<br /> In April 2004, bare root seedlings of Amorpha fruticosa and Corylus americana were placed with their roots in pea gravel with and without 10% sand (v/v) incorporated and with 0, 10, 20, 30 or 40% (v/v) calcined clay (TerraGreen) incorporated. In October 2004, seedlings were removed from the gravel and their height caliper and fresh weight were determined before they were field planted. For both species, plants were larger in mixtures containing more than 10% calcined clay than in un-amended gravel, regardless of whether sand was present. Amorpha and Corylus seedlings were largest in gravel containing 20% and 40% clay, respectively. <br /> In April 2005, a greenhouse study was established in which seedlings of Gymnocladus dioicus were grown in the above mixtures. In July, seedling growth was quantified by measuring height, caliper and dry weights of roots and tops. As in the previous study, seedlings grown in mixtures containing more than 10% calcined clay were larger than those grown in un-amended mixtures. Gymnocladus seedlings grown in pea gravel containing 30% TerraGreen were more than three times as tall and 1.6 times greater in stem caliper than those grown in un-amended gravel. The positive effect of calcined clay on seedling growth may have been due to increased porosity and water and nutrient holding characteristics of the clay-amended gravel medium.<br />

Publications

Impact Statements

1. Bigtooth maple plants from selected provenances have the potential to tolerate saline conditions. These plants can provide an alternative plant for use in landscapes limited by water quality (i.e. high salt levels). The tissue culture protocols provide a method to rapidly propagate bigtooth maple by micropropagation.
2. Key strategies useful in implementing landscape policies and designing urban landscape for water conservation programs in New Mexico have been developed and implemented. These will help reduce water use in landscapes.
3. Oklahoma research has shown that fungicides are not very effective at controlling anthracnose on Euonymus fortunei, but altering cultural practices can reduce disease incidence significantly. One Oklahoma nursery estimates that they saved about $45,000 during the 2004 growing season by eliminating fungicide sprays to control anthracnose on Euonymus fortunei, and growing the crop under shade rather than in full sun. Use of black plastic under pots appears to further reduce disease incidence.
4. The Missouri Gravel Bed is a technique that facilitates the planting of trees and shrubs bare root. Bare root plants are less expensive to harvest and ship and are easier to handle. Until recently, it was assumed that bare root plants must be planted while in the dormant condition, which greatly restricts the planting season. Results of this project have shown that trees and shrubs can be placed in a bed of pea gravel when dormant and planted at any time of the year with high survival rates.

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Report Information

Participants

Brief Summary of Minutes

Accomplishments

A summary of accomplishments at the participating institutions is presented below:<br /> At Michigan State University, research and outreach was conducted on production and flowering of herbaceous perennials and establishment of green roof technology. Cameron spent 6 months in Australia on sabbatical leave working in landscape ecology related to Eucalyptus distribution related to germination requirements. In Oklahoma, during the 2006 growing season, we completed the second growing season for several research projects. Most of the research studied the effect of various fungicides on control of anthracnose caused by Colletotrichum gloeosporioides on wintercreeper euonymus (Euonymus fortunei). This research confirmed the results of previous studies that showed the most fungicides tested are ineffective in controlling anthracnose on wintercreeper euonymus. Mancozeb decreases but does not eliminate disease symptoms while other fungicides tested including thiophanate methyl and chlorothalonil provide little disease suppression. Cultural practices including growing containerized plants on black plastic sheeting rather than on gravel and periodic application of sodium hypochlorite to the surface of the growing area around the containers were also ineffective at reducing disease symptoms. At the University of Minnesota, following research and extension activity was conducted. <br /> Plant breeding and cultivar development. Rosa: We have terminated further crosses in the breeding effort. We will continue to evaluate the currently existing germplasm which includes; seedlings from last years crosses that will be planted out this spring and summer, seedling blocks in the ground at the Horticultural Research Center, and eight additional selections in regional trials at Grand Rapids, Morris, and Rosemount, MN. (w/ Kathy Zuzek). We have signed an exclusive license with Bailey Nurseries, Inc. to market and sell 3 polyantha rose selections (Rosa 251, Rosa 215, Rosa 320). These have been trademarked as Northern Accents Sven", Ole", and Lena", respectively. Approximately 2,000 plants of each will be available for commercial sales this summer. We currently have 17 advanced rose selections in regional trials, i.e. Grand Rapids, Morris, Rosemount, Minn. Fifteen University of Minnesota advanced rose selections are currently being evaluated with Bailey Nurseries, Inc. at their testing sites across North America to determine how broadly adapted the selections are. (w/ Debbie Lonnee, and Johnathan Pedersen, Bailey Nurseries, Inc.). Rhododendron: Current efforts with deciduous azalea breeding include production of seedlings with improved foliage quality, i.e. lower levels of powdery mildew and better fall color, later flowering, i.e. mid-June to August, and improved flower fragrance. Approximately 300 seedlings which had been evaluated for the last three years in containers were planted into seedling blocks in Spring 2007. No new crosses were made in 2006. Nine selections have been made since 2002. Eight selections are in production/propagation trials with Mountain Shadow Nursery, Inc. AZ 619 - Wine red flower color, good foliage, AZ 353  Orange/Pink/Raspberry blend, AZ 554 - Red flower color, good foliage, AZ 362  Double-flowered yellow, fragrant, AZ 430  Orange/Burnt orange blend, floriferous, AZ 626 (2005 selection)  Soft tangerine/peach, AZ 625 (2005 selection)  Large-flowered double, cream/pink/orange blend, AZ 493  Double-flowered, fragrant pink. When we have clones propagated, all will be moved into an advanced second test replicated trial (w/ Steve McCulloch, Mountain Shadow Nursery). Acer: A trial planting of several advanced selections of four maple taxa (17 genotypes) was established at the NCROC in Grand Rapids, MN in May, 2004. One and two-year old grafted trees were established in three replicate completely randomized plantings. The winter climate at Grand Rapids will enable a more rapid assessment of cold tolerance than has been possible in Chanhassen in recent years. In addition, the planting should allow us to ascertain the suitability of the selections for USDA zone 3 landscapes. Acer platanoides x A. truncatum hybrids were completely killed at Grand Rapids where midwinter temperatures fell to 48 F (-44 C) in January 2005. However, these hybrids were the best-performing trees at the dry and windy UMORE Park trial site, suggesting they may be valuable trees for harsh urban planting sites in USDA zone 4. Our nursery cooperators are very impressed with the hybrids. Five of the six red and Freeman maple selections, including the programs newest introduction, FirefallTM maple, performed well at Grand Rapids. Two of the seven sugar maple selections experienced substantial cold injury at Grand Rapids and appear unsuitable for use in USDA zone 3a. Several other sugar maples experienced varying amounts of injury among replications, possibly due to microclimatic variations in temperature and/or soil drainage. Plantings of these same maple genotypes were also established at the University of Minnesota Landscape Arboretum (Chanhassen), UMORE Park (Rosemount), Bachmans Production Nurseries, and Laws Nursery, Inc. (Farmington and Lakeville, MN respectively). The later plantings will give us information regarding how well the trees grow and respond in a production setting. These plantings represent the first commercial nursery trials the project has ever undertaken (w/ Steve McNamara, Shengrui Yao, John Daniels, Bachmans, Inc. and Tim Power, Laws Nurseries). In all likelihood, the large tree breeding program along with any other taxon for which we can not propagate clonal plants in house will be phased out over the next 3-5 years. The variability created with unknown rootstocks and time and effort needed to manage these long-term programs are too great given our current staffing and budget situation. Other taxa: Bailey Nurseries, Inc. has signed an exclusive license to market and distribute our Wisteria macrostachys clone Betty Matthews. A trademark name and marketing plan will be presented in March. Plants should be commercially available in 2008. We continue to evaluate Weigela florida seedlings resulting from crosses between larger statured, cold hardy cultivars Red Prince and White Prince and the less cold-hardy, dwarf cultivar Minuet at the HRC. This summer, staff from Bailey Nurseries made 15 selections from the plot and testing agreements were signed to allow them to continue advanced testing. In 2006 crosses were made between selections from the initial F1 populations and backcrosses were made to Minuet. Over 700 seedlings from these crosses were planted for field evaluations this spring (w/ Steve McNamara, Debbie Lonnee, and Jonathan Pedersen, Bailey Nurseries, Inc.). A field evaluation consisting of 13 half-sib families of Ribes aureum var. villosum (Clove currant) was established at the HRC in May 2006. Seed was obtained from the National Clonal Germplasm Repository in Corvallis, Oregon. Surprisingly, no named cultivars of Clove currant exist, considering the bright yellow, early spring flower display and the rich, heavy clove fragrance emitted by the flowers. Plants are being evaluated for form, size, flower phenology, productivity, and disease resistance (w/ Steve McNamara). Seed collections of Lindera benzoin (Spice bush) were made in October in southwestern Michigan. In addition, 500 seedlings derived from seed collected in wild populations in Ottawa County, Michigan have been potted and are being grown on for field evaluation. Spice bush is a shade tolerant understory shrub native to USDA Plant Hardiness Zone 5 locations in the eastern U.S., not including Minnesota. Broken twigs emit a pleasant spicy odor. Early spring, yellow flowers result in a brilliant scarlet colored fruit in September/October. No named cultivars currently exist in the industry. (w/ Steve McNamara)<br /> Plant Disease Research<br /> Rosa black spot disease. For the past five years we have been involved in investigations of rose black spot disease. Publications resulting from Vance Whitakers masters thesis work describe culturing, long-term storage, race and molecular diversity of the black spot disease of rose, Diplocarpon rosae. Black spot is the most significant disease of rose worldwide. Vance Whitaker began work on his Ph.D. in January 2006. In February, 2006 he applied for and was awarded an NSF Central European Summer Research Institute Science and Engineering Fellowship to study with Dr. Thomas Debener, one of the worlds foremost experts on rose blackspot resistance genetics, in Hannover, Germany. Our current efforts involve a candidate gene approach to identifying black spot resistance genes in rose germplasm. We are targeting resistance gene analogs (RGAs). A number of RGAs have been identified and sequenced. Current efforts involve development of markers based on the RGA sequences to screen rose germplasm for additional resistance genes (w/ Jim Bradeen, Plant Pathology). Cryptodiaporthe canker: We have initiated a project to identify resistance to this disease in Pagoda dogwood (Cornus alternifolia). The canker disease is the primary limiting factor to Pagoda dogwood gaining significance in the upper Midwest Landscape Nursery industry. Currently we have collected seed from native populations extending from Zone 2 locations in Northern Minnesota to Zone 4 locations in the seven county metropolitan region of Minnesota. We have also canker samples from several diseased Pagoda dogwood trees in Minnesota and have cultured the inciting organism, Cryptodiaporthe corni. We have re-initiated efforts to develop seedling screening protocols which will allow us to begin the first efforts to develop canker resistant Pagoda dogwoods. In addition we are developing plans to study the epidemiology of the pathogen (w/ Jennifer Juzwik, USDA Forest Service/Plant Pathology). <br /> Environmental Stress Research - Birch abnormal growth syndrome. We have concluded experiments designed to determine the cause of stunting, necrosis, and distorted growth exhibited by river birches growing in artificial growing media. These symptoms showed-up as we attempted to screen birch germplasm for elevated pH tolerance. Experiments to determine the cause have included insect exclusion, manipulation of soil types, investigations into the role of soil microorganisms, and the role of various micro- and macronutrients. Interestingly, similar symptoms have been detected in pecan orchards, where symptoms are alleviated with Ni treatments. Mineral soils and Ni treatments alleviated the BAGS symptoms in our experiments. Results will be submitted in a manuscript (w/ Steve McNamara, Carl Rosen, Soil Sciences). Cold hardiness screening. Every year beginning in October we begin testing woody plants for cold hardiness in programmed freezer tests. Beginning in October allows us to evaluate the particular plants acclimation process. January tests allow us to determine a particular plants mid-winter hardiness. Continued testing through April allow us to evaluate a particular plants de-acclimation process. We routinely test advanced selections from our breeding program, azalea, rose, trees, and various shrubs. Information from the tests is used in the selection process. Ultimately, the information is used to describe new cultivars to the nursery industry. Periodically we test groups of cultivars from various species that are relatively unknown in the upper Midwest. In 2005 and 2006 we tested new and relatively unknown Clethra and Weigela cultivars respectively. A number of new cultivars, with unknown cold hardiness, from both species are showing up in garden centers in Minnesota. The Weigela florida cultivar Midnight Wine has proven quite winter tender for local growers, despite claims to the contrary from the hybridizers. Results from our freezer tests should allow the local industry to determine not only how cold hardy the cultivars are, but also in what part of the winter problems develop (w/ Steve McNamara). At Utah State University, the investigators continued work on water use of shade trees in contrasting humid and arid climates. Also conducting work on cultivar development in Eriogonum corymbosum, a small, late-blooming shrub native to the Intermountain West that has wide variability in flower color, plant size, crown form, and leaf size and color. Purdue University representatives determined factors resulting in bark cracking of ornamental woody species. (with Hannah Mathers, The Ohio State University). Their continuing project includes evaluation of elms resistant to Dutch Elm Disease (with Cliff Sadof, Purdue Univ. Dept of Entomology), and identification and evaluation of cold hardy American snowbell (Styrax americanus) for landscape plantings in northern climates (with Sally Weeks, Purdue Dept of Forestry and Eric Oesterling, Penn State Extension Agent, Westmoreland Co., Pa.). Preliminary research at the University of New Hampshire showed that certain species of plants produced and over-wintered above ground in fabric containers may survive whereas plants in plastic containers have a high mortality rate. Testing of several species shows a lack of correlation between root and shoot cold hardiness of woody shrubs. Carbohydrate analyses of fall root samples showed a higher level of glucose in Viburnum trilobum roots in fabric containers compared to plastic; root mass was also significantly higher of plants over-wintered and grown on for an additional growing season. Prototype insulating pot covers are being tested and increased plant survival over uncovered plants in 2006-07. University of Illinois reported that organic mulches treated with pre-emergent herbicides (Diuron and Surflan) were found to provide equal or better weed control of Poa annua (annual bluegrass), Senecio vulgaris (common groundsel), and Capsella bursa-pastoris (shepherds purse) in containers than when applied with water as a carrier. The organic carriers with herbicide sprays gave efficacy visual ratings equivalent to water as a carrier and at the same time provided a reduction in phytotoxicity of the Diuron on Hetz Midget American arborvitae. Pine bark treatments increased crop plant biomass for Goldflame Japanese spirea as compared with no organic mulch treatments. Landscape leaf-waste pellets as a carrier produced equivalent efficacy and phytotoxicity ratings to conventional spray application of pendimethalin and prodiamine on both chrysanthemum and wintercreeper. The leaf-waste pellets were not an effective carrier for isoxaben. In addition, bare-root liner plants of four taxa of common landscape trees, Acer platanoides, Fraxinus Americana, Fraxinus pennsylvanica, and Gleditsia triacanthos inermis, were planted in the field at three depths to determine the effect of planting depth on tree performance. Planting depths included: 1) the first branch root just below the surface, 2) the first branch root 15 cm below the surface and 3) 30 cm below the surface. Stem caliper and shoot and root growth were measured over two seasons. After two seasons of growth, increasing depth increased the caliper of the white ash, honeylocust and maple. The dry mass of the roots of white ash increased with planting depth. Root density ratings decreased with increasing depth for the green ash, white ash, and Norway maple. The most shallow plants required staking to maintain their upright position in the first season. Texas A&M University accomplishments included: (1) bedding plant greenhouse and garden performance trials were continued both for the spring and fall seasons with industry support. Also, an effort geared toward trials of new material for a mid-winter color market was continued. Several hundred entries were trialed from the major seed companies doing business in the U.S. Data from these trials were presented at Field Days and programs to target audiences. In addition, a web site for presentation of the results and images from the trials was updated and improved. Trials were continued at cooperative sites at the Dallas Center and the Dallas Arboretum. In addition, the number of accessions in the Research and Demonstration Garden was expanded showcasing roses that have been proven disease resistant in the Overton trials, perennial entries in the bedding plant trials, Texas Superstar (CEMAP) plants, and other plants showing potential for introduction to the Texas Greenhouse/Nursery industry. Development of a new program called the North Texas Winners Circle was continued to denote the best performers of the bedding plant trials at the Overton Center, Dallas Center, and Dallas Arboretum locations; (2)continued role Convener and Organizer of the Fourth International Rose Symposium which was held in Santa Barbara, California in September 2005. Also served as Editor of a volume of Acta Horticulturae that will serve as the published proceedings for the symposium. This work is now completed and at the publisher; (3)funding was secured and planning done for installation of a model landscape to measure water use of several ornamental species in a landscape setting using soil moisture probes. This work is being done in cooperation with Dr. R. White (Soil and Crop Sciences). Equipment is installed and tested with the remaining installation to be done in fall of 2007; (4)secured funding from the federally funded IR4 program to study the effects of growth regulators on postharvest performance of several ornamental greenhouse and woody species; (5) studied the effects of E-beam technology on geranium cuttings as a possible method of disease control in cooperation with W. Mackay (TAES - Dallas) and S. Pillai (E-beam facility - College Station). At the University of Florida, a water conservation workshop was presented at ASHS in collaboration with colleagues from the nation; a constructed wetland system was assessed for its efficacy in removing nitrogen from nursery runoff; and native woody species were assessed for nitrogen uptake and shade tolerance (in collaboration with Dr. Mack Thetford, UF). Penn State University reported that Pennsylvania researchers continue to evaluate the susceptibility of Tsuga species for susceptibility to Hemlock Woolly Adelgid and Elongate Hemlock Scale through direct challenges in the field and under greenhouse settings. In addition, research is underway to evaluate selected Abies for adaptability to diverse climatic and environmental conditions across USDA Hardiness Zones 5 and 6. Research results are being finalized for publication by a PhD candidate on the invasive potential of Acer platanoides and Viburnum opulus cultivars. White pine weevil management research on trapping methods, growth degree day confirmation, and pesticide efficacy trials continue. University of Missouri accomplishments included a greenhouse study in which seedlings of Gymnocladus dioicus were grown in mixtures of pea gravel with 0, 10, 20, 30 or 40% (v/v) calcined clay with or without 10% sand. After 18 weeks in the gravel media, seedling growth was quantified by measuring height, caliper and dry weights of roots and tops. As in the previous study, seedlings grown in mixtures containing more than 10% calcined clay were larger than those grown in unamended mixtures. Gymnocladus seedlings grown in pea gravel containing 30% TerraGreen were more than three times as tall and 1.6 times greater in stem caliper than those grown in unamended gravel. In 2006, the greenhouse study was repeated and the effects of incorporating calcined clay on porosity and water holding characteristics were quantified. This research showed that addition of calcined clay to a gravel based growing medium significantly increased the water holding ability of the medium while maintaining acceptable air-filled porosity and confirmed the growth enhancement observed previously. University of Arkansas reported that The University of Arkansas Plant Evaluation program, initiated in 1999, has evaluated over 115 woody ornamental plants at three trial locations across Arkansas representing the three climatic zones. Results from these evaluations are reported at state, regional, and national meetings and in trade publications. Annual reports are distributed to participants in the trial. Annual reports, plant growth data, and photographs are maintained on a University website. Annually, the industry is provided with a brief written program summary and list of potential nursery sources. This summary provides an efficient means for the wholesale industry to obtain this plant material. University of Idaho member was involved in three studies. The first study found that 2-0 plug seedlings of pinyon pine (Pinus edulis) and subalpine fir (Abies lasiocarpa) could be grown successfully in field or gravel beds and under 55% shade. Fir seedlings survived best if they received the shade treatment compared to full sun. In another study, pinyon pine and subalpine fir seedlings grew well in fabric and plastic containers, with fir seedlings producing significantly more roots if grown in fabric bags. In the third study, switchcane can be micropropagated by single-node rhizome sections if roots are attached to the explant. In addition, culm explants grew better in liquid or half-strength phytagel medium rather than regular agar at full strength (0.6%). <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />

Publications

Zollinger, N., R. Koenig, T. Cerny-Koenig, and R. Kjelgren. 2007. Relative salinity tolerance of Intermountain Western United States native herbaceous perennials. HortScience 42(3):529-534.<br /> Kjelgren, R. 2007. Agricultural Experiment Station Faculty and Administrator Attitudes and Perceptions Regarding Placing Research Results on the World Wide Web HortTechnology 17:95-101<br /> Kjelgren, R., and T. Cerny-Koenig. 2006. Evaluating a line source irrigation system for determining water requirements of herbaceous perennials . J. Environ. Hort. 24:225229. <br /> Cardoso, G., R. Kjelgren, Teresa Cerny-Koenig, and Rich Koenig. 2006. Pot-in-pot production of six Intermountain West native herbaceous perennial species grown in containers. J. Environ. Hort. 24: 77-83.<br /> Montague, T, and R. Kjelgren. 2006. Use of thermal dissipation probes to estimate water loss of containerized landscape trees. J. Environ. Hort. 24:95-104.<br /> Zollinger, N., R. Kjelgren, T. Cerny-Koenig, K. Kopp, and R. Koenig. 2006. Drought responses of six ornamental herbaceous perennials. Scientia Horticulturae, 109:267-274.<br /> Dewey, D., P. G. Kjohnson, and R. Kjelgren. 2006. Effects of irrigation and mowing on species diversity of grass and wildflower mixtures for the Intermountain West. Native Plant J. 7:267-278.<br /> Mickelbart, M.V.*, G.S. Bender, G.W. Witney, C. Adams, and M.L. Arpaia. 2007. Effect of clonal rootstocks on Hass avocado yield components, alternate bearing, and nutrition. Journal of Horticultural Science and Biotechnology 82:460-466.<br /> Teixeira, E.I.*, D.J. Moot, and M.V. Mickelbart. 2007. Seasonal patterns of root C and N reserves of lucerne crops (Medicago sativa L.) grown in a temperate climate were affected by defoliation regime. European Journal of Agronomy 26:10-20.<br /> Mickelbart, M.V.*, P. Chapman, and L. Collier-Christian. 2006. Endogenous levels and exogenous application of glycinebetaine to grapevines. Scientia Horticulturae 111:7-16. <br /> Mickelbart, M.V.*, S. Melser, and M.L. Arpaia. 2007. Salinity-induced changes in ion concentrations of Hass avocado trees on three rootstocks. Journal of Plant Nutrition 30:105-122. <br /> Mickelbart, M.V.*, S. Larsen, R. Heath, and M.L. Arpaia. 2007. Changes in photosynthesis during flush development in avocado (Persea Americana Mill.). HortScience 42(4):992. [Abstract]<br /> Mickelbart, M.V.*, N. Wasmer, S. Revankar, and L. Collier-Christian. 2007. Effects of supplemental sulfur on growth of three woody ornamental species. HortScience 42(4):994. [Abstract]<br /> Yoo, C.Y.*, J.B. Jin, K. Miura, Y. Hua, M. Gosney, M.V. Mickelbart, R.A. Bressan, and P.M. Hasegawa. 2007. Ca2+/CaM signaling through AtGTL1 mediates drought stress adaptation. Plant Physiology, Plant Biology 07, Final Program and Abstract Supplement p. 108. [Abstract]<br /> Gosney, M.J. and M.V. Mickelbart*. 2006. Measuring water loss in Thellungiella halophila. The Biology of Transpiration: From Guard Cells to Globe, October 10-14, 2006, Snowbird, Utah. [Abstract]<br /> Moot, D.J.*, E. Teixiera, H.E. Brown, and M.V. Mickelbart. 2006. Changes in total biomass and N content of taproots of alfalfa crops under contrasting defoliation frequencies. 40th North American Alfalfa Improvement Conference and 19th Trifolium Conference, July 16-19, 2006. Ramada Inn Airport at Mall of America in Bloomington, Minnesota, USA. [Abstract]<br /> http://www.naaic.org/meetings/national/2006meeting/proceedings/clovers&medicago.htm<br /> Mickelbart, M.V. 2007. Horticulture and global warming. Indiana Nursery and Landscape News 67(4):32. <br /> Mickelbart, M.V. 2007. Is vitamin B1 useful when transplanting? Indiana Nursery and Landscape News 67(3):34. <br /> Mickelbart, M.V. 2007. Pruning and tree caliper. Indiana Nursery and Landscape News 67(2):36. <br /> Mickelbart, M.V. 2006. Managing for minimal losses in the event of Sudden Oak Death infestation. Indiana Nursery and Landscape News 66(6):30-31. <br /> Mickelbart, M.V. 2006. Tree planting depth and mulch. Indiana Nursery and Landscape News 66(4):34. <br /> Dennis, J.H. and M.V. Mickelbart. 2006. Risk management principles IV: Financial risk. Indiana Nursery and Landscape News 66(4):26-28. <br /> Mickelbart, M.V. 2006. Is there enough bark to meet landscape demands? Indiana Nursery and Landscape News 66(3):36<br /> Dennis, J.H. and M.V. Mickelbart. 2006. Risk management principles III: Human risk. Indiana Nursery and Landscape News 66(3):34-35. <br /> Mickelbart, M.V. 2006. How do plants respond to warm winters? Indiana Nursery and Landscape News 66(2):38. <br /> Dennis, J.H., B. Taylor, and M.V. Mickelbart. 2006. Risk management principles II: Marketing risk. Indiana Nursery and Landscape News 66(2):32-34. <br /> Mickelbart, M.V. 2006. Deer control in nurseries and landscapes. Indiana Nursery and Landscape News 66(1):34.<br /> Dennis, J.H., B. Taylor, and M.V. Mickelbart. 2006. Risk management principles I: Production risk. Indiana Nursery and Landscape News 66(1):32-33. <br /> Mickelbart, M.V. and J. Beckerman. 2006. What you need to know about P. ramorum. American Nurseryman 204(10):20-23. <br /> Dennis, J.H. and M.V. Mickelbart. 2006. Decreasing marketing risk. Ohio Florists Association Bulletin, May/June Issue, Number 896.<br /> Neal, Catherine. 2006. Winter Survival of Shrubs in Fabric Containers in a Zone 5 Climate. Proc. SNA Research Conference 51: 52-54. <br /> Neal, Catherine and Richard C. Beeson. 2007. Viburnum Root Mass and Fall Carbohydrate Levels as Affected by Container Type. HortScience 42 (4): 862.<br /> Neal, Catherine, Jeffrey Schloss, Stanley Swier, John Roberts, Margaret Hagen, Amy Ouellette, Sadie Puglisi, Mary Tebo and Lauren Chase-Rowell. 2007. Landscaping at the Waters Edge: an Ecological Approach. Univ. of New Hampshire Cooperative Extension, Durham NH. 92 pgs.<br /> Klett, J.E. 2006. Superior Annuals. Colo Green 22 (1) 52-54.<br /> Klett, J.E. 2006. Unusual Woody Plants. Colo Green 22 (2) 61-62.<br /> Klett, J.E. 2006. Underused Woody Plants. Colo Green 22 (3) 61-62.<br /> Klett, J.E. 2006. Proven Herbaceous Perennials. Colo Green 22 (4) 61-62.<br /> Klett, J.E. and MacDonald, R. 2006. Plant Select® Woody Plant Trials. Colo Green 22 (5) 61-62.<br /> Klett, J.E. 2006. More Unusual Woody Plants from Research Plots. Looseleaf 23 (1) 18.<br /> Ounsworth, M. and Klett, J.E. 2006. Water Requirements of Landscape Shrubs and Turfgrass. Looseleaf 23 (2) 8.<br /> Klett, J.E. 2006. Plant Select® for 2007. Looseleaf 23 (4) 12-13.<br /> Ounsworth, M. and Klett, J.E. 2006. Drought Avoidance and Drought Tolerance. Looseleaf 23 (5) 12-13.<br /> Klett, J.E. 2006. Superior Annuals from the 2006 Trials. Looseleaf 23 (6) 12-13.<br /> Litus, G. and Klett, J.E. 2006. Drought Stress and Recovery in Green Ash. HortScience 41 (4) 1009 (Abstract).<br /> Harris, J. R. 2007. Transplanting large trees. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 2007 2, No. 024<br /> Richardson-Calfee, L.E., Harris, J.R., and Fanelli, J.K. 2007. Posttransplant root and shoot growth periodicity of sugar maple. J. Amer. Soc. Hort. Sci. 132:147-157.<br /> Day, S.D., and Harris, J.R. 2007. Fertilization of red maple (Acer rubrum) and littleleaf linden (Tilia cordata) trees at recommended rates does not aid tree establishment. Arboric. Urb. For. 33: 113-121.<br /> Samtani, J.B., G. J. Kling, H.M. Mathers, and L. Case. 2007. Rice hulls, leaf-waste pellets, and pine bark as herbicide carriers for container-grown woody ornamentals. HortTechnology: 17(3):289-295. <br /> Samtani, J.B., G. J. Kling, and D. J. Williams. 2006. Leaf-waste pellets as a herbicide carrier for container-grown ornamental plants. Weed Tech. 20:942-949.<br /> Schuch, U.K., H.B. Pemberton, and J.J. Kelly. 2007. Post harvest moisture loss from bare-root roses affects performance of containerized plants. HortScience 42(3):622-625.<br /> Byrne, D.H., N. Anderson, and H.B. Pemberton. 2007. The use of Rosa wichuraiana in the development of landscape roses adapted to hot humid climates. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae. In Press.<br /> Pemberton, H.B. and U.K. Schuch. 2007. Relationship between visually determined starch content and flowering of containerized field-grown garden roses. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae. In Press.<br /> Shupert, D., D.H. Byrne, and H.B. Pemberton. 2007. Inheritance of flower traits, leaflet number, and prickles in roses. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae. In Press.<br /> Pemberton, H.B. and R.I. Cabrera. 2006. Fourth international symposium on rose research and cultivation. Chronica Horticulturae 46(2):33-34.<br /> Pemberton, H. Brent and W.R. Roberson. 2007. Effects of plant growth regulators on branching and growth of azalea and rose. HortScience 42(4):939-940 (Abstr.).<br /> Pemberton, H. Brent and W.R. Roberson. 2007. Effects of plant growth regulators on postharvest characteristics of geranium and impatiens. HortScience 42(4):925 (Abstr.).<br /> Denny, G., M. Arnold, W. Mackay, L. Lombardini, and H.B. Pemberton. 2007. Effect of provenance on drought tolerance of Taxodium distichum. HortScience 42(4):911 (Abstr.).<br /> Bowen-OConnor, C.A., R. St. Hilaire, J. Hubstenberger, C.A. Baca, and D.M.<br /> VanLeeuwen. 2007. In vitro propagation of Acer grandidentatum Nutt. In vitro Cellular and Developmental Biol. 43: 40-50. <br /> Bsoul, E., R. St. Hilaire, and D. VanLeeuwen. 2007. Bigtooth maples from selected provenances effectively endure deficit irrigation. Hortscience 42: 11671173.<br /> VanLeeuwen, D., R. St. Hilaire and E. Bsoul. 2006. Statistical analysis of mixed model factorial experiment with missing factor combinations: The case of asynchronous cyclic drought data. J. Amer. Soc. Hort. Sci. 131: 201-208.<br /> Bsoul, E., R. St. Hilaire, and D. VanLeeuwen. 2006. Bigtooth maples exposed to asynchronous cyclic irrigation show provenance differences in drought adaptation mechanisms. J. Amer. Soc. Hort. Sci. 131:459-468.<br /> Hurd, B., R. St. Hilaire, and J. White. 2006. Residential landscapes, homeowner attitudes and water-wise choices in New Mexico. HortScience 16: 241-246<br /> Kelley, K.M., J.R. Concklin, J.C. Sellmer, and R.M. Bates. 2006. Invasive Plant Species: Results of a Consumer Awareness, Knowledge, and Expectations Survey Conducted in Pennsylvania. Journal of Environmental Horticulture 24 (1) 53-58.<br /> Durhman, A.K., D.B. Rowe, and C.L. Rugh. 2007. Effect of substrate depth on initial growth, coverage, and survival of 25 succulent green roof plant taxa. HortScience 42(3):588-595.<br /> Getter, K.L. and D.B. Rowe. 2007. Effect of substrate depth and planting season on Sedum plug establishment for green roofs. J. Environ. Hort 25(2):95-99.<br /> Durhman, A.K., D.B. Rowe, and C.L. Rugh. 2006. Effect of watering regimen on chlorophyll fluorescence and growth of selected green roof plant taxa. HortScience 41(7):1623-1628.<br /> Getter, K.L. and D.B. Rowe. 2006. The role of green roofs in sustainable development. Hort Science 41(5):1276-1285.<br /> Rowe, D.B., M.A. Monterusso, and C.L. Rugh. 2006. Assessment of heat-expanded slate and fertility requirements in green roof substrates. HortTechnology 16(3):471-477.<br /> Whitaker, V.M., K. Zuzek, and S.C. Hokanson. 2007. Resistance of 12 rose genotypes to 14 isolates of Diplocarpon rosae Wolf (rose blackspot) collected from eastern North America. Plant Breeding 126:83-88.<br /> Whitaker, V.M., J.M. Bradeen, and S.C. Hokanson. 2007 Distribution of rose blackspot (Diplocarpon rosae Wolf) genetic diversity in eastern North America using AFLP and implications for resistance screening. Journal of the American Society for Horticultural Science 132:532-540. <br /> Whitaker, V.M., K. Zuzek, J.M. Bradeen, and S.C. Hokanson. Culturing and long-term storage of virulent races of the rose blackspot pathogen Diplocarpon rosae Wolf. Acta Horticulturae<br /> Zuzek, K. and S.C. Hokanson. Shrub rose breeding at the University of Minnesota. Acta Horticulturae<br /> Zlesak, D., K. Zuzek, and S.C. Hokanson. Rose pollen viability over time at varying storage temperatures. Acta Horticulturae<br /> Takeda, F., P. Perkins-Veazie, H.J. Swartz, and S.C. Hokanson. 2006. Strawberry transplant production and performance in annual plasticulture system in the eastern United States. Acta Horticulturae 708:213-216.<br /> Pinzon, O.P., R.M. Houseman and C.J. Starbuck. 2006. Feeding, weight change, survival, and aggregation of Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) in seven varieties of differentially-aged mulch. J. Environ. Hort. 24:1-5.<br /> Bohnert, C.A. 2006. Effects of amending a gravel based growing medium with calcined clay on medium physical properties and growth of gymnocladus dioicus seedlings. M.S. Thesis. University of Missouri.Abstract - Workshop<br /> Starbuck, C.J. 2006. The Missouri Gravel Bed: A Method Facilitating Season-long Planting of Bare Root Trees and Shrubs. HortSci. 41(4) July. Podcast and PowerPoint at http://ashs.org/resources/videoworkshopseries.html or<br /> http://ashs.org/resources/horttalks/detail.lasso?id=78 <br /> Schrader, J.A., M.A. Kroggel, and W.R. Graves. 2007. Nodulation and nitrogen-fixing capacity of rhizobial isolates from China in symbiosis with Maackia amurensis. Journal of Environmental Horticulture 25:47-50.<br /> Schrader, J.A., W.R. Graves, S.A. Rice, and J.P. Gibson. 2006. Differences in shade tolerance help explain varying success of two sympatric Alnus species. International Journal of Plant Sciences 167:979-989.<br /> Stewart, J.R., W.R. Graves, and R.D. Landes. 2006. Cold hardiness and vernal bud break of Rhamnus caroliniana and Rhamnus cathartica. Journal of the American Society for Horticultural Science 131:345-351.<br /> Stewart, J.R. and W.R. Graves. 2006. Photosynthesis, growth, carbon allocation and fruit load of Frangula caroliniana and Rhamnus cathartica. International Journal of Plant Sciences 167:1161-1168.<br /> Graves, W.R., J.A. Schrader, and J. Sharma. 2006. Cold hardiness of the rare Dirca occidentalis: Comparisons to Dirca palustris from disparate provenances. Journal of Environmental Horticulture 24:169-172.<br /> J. Zhu, A. Zhang, K. Park, T. Baker, B. Lang, R. Jurenka, J.J. Obrycki, W.R. Graves, J.A. Pickett, D. Smiley, K.R. Chauhan, J.A. Klun. 2006. Sex pheromone of the soybean aphid, Aphis glycines Matsumura, and its potential use in semiochemical-based control. Environmental Entomology 35:249-257.<br /> Graves, W.R. 2006. Distribution and reproduction of Dirca occidentalis (western leatherwood). The Four Seasons (East Bay [Berkeley, California] Regional Parks Botanic Garden) 12(3):54-61.<br /> Kratsch, H.A., R.J. Gladon, and W.R. Graves. 2006. Aeroponics system for control of root-zone atmosphere. Environmental and Experimental Botany 55:70-76.<br /> Struve, D., J. Sammons, J. Altland, B.L. Appleton, M. Arnold, R. Beeson, J. Cole, and S. Clark. 2007. A team effort. Amer. Nurseryman 205(4): 36-38, 40-43.<br /> Boyer, C.R., J.C. Cole, and K.E. Conway. 2007. Effectiveness of copper sulfate pentahydrate, mancozeb, and hydrogen dioxide in controlling anthracnose on wintercreeper euonymus. J. Environ. Hort. 25:21-26. <br /> Schupbach-Ningen, S.L., J.C. Cole, J.T. Cole, and K.E. Conway. 2006. Chlorothalonil, trifloxystrobin, and mancozeb decrease anthracnose symptoms on three cultivars of wintercreeper euonymus. HortTechnology 16:211-215.<br /> Graves, W.R., J.A. Schrader, and J. Sharma. 2006. Cold Hardiness of the rare Dirca occidentalis: comparisons to Dirca palustris from disparate provenances. Journal of Environmental Horticulture 24(3): 169-172.<br /> Sharma, J., G.W. Knox, and M.L. Ishida***. 2006. Root formation on stem cuttings of yellow-flowered cultivars of Magnolia is influenced by time-after-budbreak and IBA. HortScience 41(1): 202-206. <br /> Sharma, J., J.G. Norcini, and G.W. Knox. 2006. Organic slow release fertilizer for minimizing nutrient loss and optimizing growth of Hemerocallis. Proceedings of Southern Nursery Association Research Conference 51: 544-548. <br /> Sharma, J., D.Z. Haman, and R.C. Beeson. 2006. Water-conserving and runoff-reducing production systems for containerized plants: Some examples of recently developed technologies. 4 pp. EHN-1048, Institute of Food and Agricultural Sciences, University of Florida. <br /> Marshall-Mattson, K. and J. Sharma. 2006. An annotated bibliography of all literature and reports on Platanthera praeclara. Document of the US Fish and Wildlife Office, Minneapolis, Minnesota.<br /> 2006. Rain Gardens. 8(8). 10 April. UF NFREC Newsletter.<br /> Knox, G.W. and J. Sharma. 2006. Propagation Protocols for Yellow-flowered Cultivars of Magnolia. Dearing, GA: The Center for Applied Nursery Research. 2 pp. http://www.canr.org/Knox%20MagnoliaRooting%20F-05.pdf<br /> Sharma, J. and M.H.S. Light. 2006. Platanthera praeclara Sheviak and Bowles, Flagship Taxa, Orchid Specialist Group, North American Region. http://www.orchidconservation.org/osg/PubArt/NARFS-Pthra_praeclara-L-En.pdf<br /> <br /> <br /> <br /> <br /> <br />

Impact Statements

1. From this research, we recommend that growers reduce their fungicide usage and instead grow wintercreeper euonymus under shade with afternoon irrigation (based on previous research). By reducing or eliminating fungicide usage, growers can reduce pesticide costs, divert attention of the pest control personnel to other, more controllable pest problems, and reduce environmental impacts of using pesticides. One large Oklahoma nursery has estimated that they save about $48,000 annually by eliminating or greatly reducing pesticide applications to wintercreeper euonymus.
2. Worked with growers to improve production techniques for herbaceous perennials and ornamental grasses. Michigan is now one of the leading states in the country in potted herbaceous perennial production. Worked with several companies on the development of greenroof technology.
3. The woody plant breeding program at the University of Minnesota is the only public breeding program in the U.S. dedicated to breeding USDA plant hardiness zone 3/4 hardy landscape plant cultivars. The three new rose releases are the only rose black spot race characterized rose cultivars available in North America.
4. The work on water use at Utah State of shade trees is being directly used in a project offering free commercial and residential landscape irrigation system evaluations in the Salt Lake City region, as a part of the recommendations given to the end user on proper irrigation practices to conserve water. The work on Eriogonum corymbosum will also be incorporated into the same irrigation evaluation program as a part of the recommendations on alternative low water landscaping.
5. In Colorado, specific performance results from annuals flower trials will help determine which new and superior flower varieties growers throughout the region will grow and market. Plant Select® plants which were introduced or recommended throughout the region means marketing more profitable plants for growers in the region. Water requirements of shrubs and turf species will help all property managers and homeowners ultimately conserve water use in landscapes.
6. Research on production and profitability of cut branch crops such as pussy willow and red-twigged dogwood has stimulated interest and planting on the part of 10-12 growers in New Hampshire. These crops can generate $40-60 per plant after three years and provide crop diversification to farms and cash flow during the off-season. Other nursery systems research in N.H. has increased by ten the number of nurseries using pot-in-pot production, which saves labor costs associated with digging and wrapping B&B plants, or moving and over-wintering container grown plants.
7. Research at University of Illinois demonstrated the utility of using waste organic products, such as landscape leaf waste, rice hulls and pine bark, to serve as carriers for common pre-emergent herbicides in container nursery production. These organic carriers gave equivalent or better weed control to traditional water carrier application, with the potential to reduce phytotoxicity to the nursery crop. The planting depth research demonstrates that in the drummer and flanagan soils of the Midwest, that deep planting of nursery stock has little to no detrimental effects or even improved shoot and trunk caliper growth in the first two years of production.
8. At New Mexico State University, one-hundred twenty people and eleven invited speakers participated in the first Annual Symposium on Efficient Water use in the Urban Landscape. Symposium made the local and regional news. Provided evidence that show many factors limit New Mexico homeowners from adopting water-conserving landscapes. Provenances of bigtooth maples that are resilient to drought and salinity were identified. An efficient micropropagation protocol for bigtooth maples was established.
9. At Penn State, during the first year of an ongoing white pine weevil management research project, efficacy trials conducted in the spring of 2006 at five different sites in eastern Pennsylvania resulted in a chemical registrant seeking a modification of an existing specimen label to include management of the white pine weevil. The active ingredient, indoxacarb, applied according to label directions provided excellent results.
10. The Missouri Gravel Bed is a technique that facilitates the planting of trees and shrubs bare root (without a soil ball). The most recent results indicate that incorporating kiln-fired clay particles into the gravel bed reduces the frequency of irrigation required to keep plants turgid and improves plant growth. This will make it easier to establish and manage a gravel bed, making it more attractive as a tool to facilitate planting of bare root nursery stock.
11. Iowa State University findings led to availability of plants of the rare species, Dirca occidentalis, that were sold in a nursery in California. Findings related to Alnus spp. impacted how trail-site cooperators who received a selection of Alnus maritima for evaluation. Acquisition of germplasm of rare species, and development of propagation protocols for those species, impacted present research expected to lead to the introduction of those species to horticultural commerce.
12. University of Idaho: (seedling gravel bed study) This study with subalpine fir and pinyon pine showed that plug plants of these two species grew well in a gravel bed or soil, but shade improved survival of subalpine fir seedlings. (seedling container production study) This study showed that plug plants of subalpine fir and pinyon pine can be grown successfully in containers. Fabric bags promoted root growth of the subalpine fir seedlings only, so the added expense of these bags for container production of this species is probably justified.

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Report Information

Participants

Bewick, Tom - USDA/CSRESS; Boyer, Nickolee  Iowa State University; Cameron, Art  Michigan State University; Coakley, Stella  Oregon State University (Administrator of WERA058); Graves, Bill  Iowa State University; Helgeson, Matt  Iowa State University; Hoffman, Bill  USDA/CSREES representative for WERA058; Hokanson, Stan  University of Minnesota; Klett, Jim  Colorado State University; Lenahan, Olivia  Iowa State University; Mathers, Hannah  Ohio State University; Merhaut, Don  University of California-Riverside; Pemberton, Brent  Texas A&M University; Peterson, Bryan  Iowa State University; Sharma, Jyotsna  University of Florida; Tripepi, Bob  University of Idaho; Zinati, Gladis  Rutgurs University

Brief Summary of Minutes

Accomplishments

Catherine Neal - Univ. of New Hampshire. Accomplishments: Completed a 3-year study of container production systems utilizing Syringa "Miss Kim" as the test species. Results clearly show superior growth of both tops and roots in below ground pot-in-pot and bag-in-pot systems compared with above-ground fabric and plastic containers. However, plants in above-ground fabric containers over-wintered very successfully whereas plants in plastic containers fared poorly. Similar results were observed in other trials with Viburnum plicatum Mariesii and Weigela florida, where all the above ground plastic container plants were winter-killed but the above ground fabric container plants survived. The positive response of plants to fabric containers is attributed to their effects on root morphology and distribution and on modifying temperatures during winter cold events as well as preventing radiant heating during the summer. <br /> <br /> James E. Klett  Colorado State University. Accomplishments: Woody and herbaceous plants continue to be evaluated for adaptability to the High Plains on a 30 ha site. Woody (95 taxa) and herbaceous plants (82 taxa) were acquired in 2007 for evaluation. Performance records for 3,300 taxa of woody and herbaceous plants were entered into a computer system, which are available on three websites. Over 1,150 varieties of annual flowers were grown and evaluated in 2007 and a performance report was published and sent to all cooperators and industry personnel in the state and region. Many vegetatively propagated annual varieties including argyranthemum, calibrachoa, coleus, geranium, New Guinea impatiens, osteospermum, petunia, and verbena have become very important bedding plant crops in the state, due to this research. In 2007, seven plant species were recommended or introduced by Plant Select®. In 2007, over 1.5 million Plant Select® labels were sold which is our best estimate of the number of Plant Select® plants sold. Over eighty demonstration gardens are displaying Plant Select® plants throughout Colorado. The multi-site woody plant trial continued at five locations throughout the state. Plants tested for five years are being evaluated and Cupressus arizonica from the 2002 planting will be a future Plant Select® recommendation. In 2008, seven additional plants are being recommended or introduced. Four herbicides: Mesotrione, Dinnethenamid, Sulfentrazone, and Dimethenamid Plus were evaluated for weed control effectiveness and phytotoxicity on six herbaceous plants with the experiment starting at three different times in Fort Collins. Sulfentrazone resulted in phytotoxicity, reduced dry weights, and some death with Echinacea purpurea. The drought tolerance study was continued in 2007 with extensive data taken on common lilac, three-leaf sumac, serviceberry, tall fescue, and Kentucky bluegrass. The tall fescue and Kentucky bluegrass showed physiological stress due to water. The shrub species with more extensive rooting systems only showed some minor stress at lower water treatments. A project determining herbaceous plant species and media type suitable to support green roofs in a semi-arid, high elevation area was initiated in 2007.<br /> <br /> William R. Graves  Iowa State University. Accomplishments: Propagated plants from a small population of Styrax americanus that is disjunct to the north from the primary distribution of this species. Genetic and physiological tests to assess the potential attributes of this northern germplasm are underway. Evaluated the genetic structure of Nyssa aquatica and examined the stress resistance of this species, which, to date, has not been examined for its horticultural value(in collaboration with J. Sharma). Assessed the capacity for Nyssa aquatica and Nyssa ogeche to be propagated asexually from stem cuttings (in collaboration with J. Sharma). Documented the overwintering capacity and landscape performance of two provenances of Callicarpa americana planted at five sites from Arkansas north to central Iowa. Continued to evaluate the horticultural potential of the three species of Dirca (Dirca palustris, Dirca mexicana, Dirca occidentalis), including research on propagation, stress physiology, and provenance variation in ornamental traits(in collaboration with J. Sharma). Studied interactions between Alnus maritima and Alnus nitida and the nitrogen-fixing Frankia that associate with these alders (in collaboration with J. Sharma and R. Hummel). Progressed toward the development of so-called bioplastic plant pots fabricated from zein, a protein from corn.<br /> <br /> Jyotsna Sharma  University of Florida. Accomplishments: Assessed mycorrhizal and genetic diversity of an endangered terrestrial orchid from the west coast. Piperia yadonii populations showed strong genetic differentiation even though all populations are located within 50 km from each other. Produced plants of Canna flaccida from seeds and tested them for Phosphorus uptake. Assessed nitrogen removal capacity of an artificial wetland at a plant nursery by studying the nitrogen dynamics and denitrification associated with plant rhizospheres. Assessed shade tolerance and nitrogen requirement of Callicarpa americana and Myrica cerifera.<br /> <br /> H. Brent Pemberton - Texas AgriLife Research, Texas A&M System. Accomplishments: Bedding plant greenhouse and garden performance trials were continued both for the spring and fall seasons with industry support. Also, an effort geared toward trials of new material for a mid-winter color market was continued. Several hundred entries were trialed from the major seed companies doing business in the U.S. Data from these trials were presented at Field Days and programs to target audiences. In addition, a web site for presentation of the results and images from the trials was updated and improved. Trials were continued in cooperation with the Dallas Arboretum. In addition, the number of accessions in the Research and Demonstration Garden was expanded showcasing roses that have been proven disease resistant in the Overton trials, perennial entries in the bedding plant trials, Texas Superstar (CEMAP) plants, and other plants showing potential for introduction to the Texas Greenhouse/Nursery industry. The award program called the North Texas Winners Circle was continued to denote the best performers of the bedding plant trials at the Overton Center, Dallas Center, and Dallas Arboretum locations. Also, work on the Texas Superstar Board continued and trials and promotions were accomplished.<br /> Continued role as Convener and Organizer of the Fourth International Rose Symposium which was held in Santa Barbara, California in September 2005. Served as Editor of a volume of Acta Horticulturae that serves as the published proceedings for the symposium. This work is now in print. Work continues on the installation of a model landscape to measure water use of several ornamental species in a landscape setting using soil moisture probes. This work is being done in cooperation with Dr. R. White (Soil and Crop Sciences, Texas A&M University). Secured funding from the federally funded IR4 program to study the effects of growth regulators on postharvest performance of several ornamental greenhouse species. These studies are being performed in cooperation with Dr. M. Reid (University of California, Davis) so that test plants can be subjected to actual shipping treatment by commercial carrier.<br /> Studied the effects of E-beam technology on geranium cuttings as a possible method of disease control in cooperation with W. Mackay (TAES - Dallas) and S. Pillai (E-beam facility - College Station). Irradiation from the E-beam killed the cuttings and a paper was published with the results. Secured funding and initiated studies on the efficacy of a new controlled release fertilizer product for bare-root forcing of dormant field grown roses. This study was completed and another study was completed for potted roses grown from liners.<br /> A study was initiated in cooperation with Dr. U. Schuch (University of Arizona) to study the water use of roses. Rooted cuttings are being grown in large pots to simulate a landscape situation. The study is being replicated at two locations to determine the effect of the climate differences between eastern Texas and southern Arizona.<br /> <br /> Stan Hokanson  University of Minnesota. Accomplishments: We continue to evaluate the Rosa germplasm remaining in the program including seedlings and advanced selections A testing agreement with Bailey Nurseries to evaluate UMNRosa 362, a red-flowered polyantha garden rose (w/ Kathy Zuzek). Polyantha rose selections UMNRosa 251, UMNRosa 215, and UMNRosa 320, named Rosa Northern Accents" Sven, Lena, and Ole respectively, are currently for sale in local nurseries and garden centers. Fifteen University of Minnesota advanced rose selections are being evaluated with Bailey Nurseries, Inc. at their testing sites across North America to determine how broadly adapted they are (w/ Debbie Lonnee, and Johnathan Pedersen, Bailey Nurseries). Current efforts with deciduous azalea breeding include production of seedlings with improved foliage quality, i.e. lower levels of powdery mildew and better fall color, later flowering, i.e. mid-June to August, and improved flower fragrance. Fourteen parental combinations were included in this years crossing with the primary goal of developing later flowering cultivars. Currently ~ 500 seedlings are being evaluated in the program. Approximately 400 of these were planted into seedling nurseries this spring. Nine selections have been made since 2002. <br /> We continue to evaluate a trial planting of several advanced selections of four maple taxa (17 genotypes) that was established at the NCROC in Grand Rapids, MN in May, 2004. Five of the six red and Freeman maple selections, including the programs newest introduction, FirefallTM maple, performed well at Grand Rapids. Two of the seven sugar maple selections experienced substantial cold injury at Grand Rapids and appear unsuitable for use in USDA zone 3a. Several other sugar maples experienced varying amounts of injury among replications, possibly due to microclimatic variations in temperature and / or soil drainage.<br /> Plantings of these same maple genotypes were also established at the University of Minnesota Landscape Arboretum (Chanhassen), UMORE Park (Rosemount), Bachmans Production Nurseries, and Laws Nursery, Inc. (Lakeville). The later plantings will give us information regarding how well the trees grow and respond in a production setting(w/ Steve McNamara, Shengrui Yao, John Daniels, Bachmans, Inc. and Tim Power, Laws Nurseries). We continue to evaluate Weigela florida seedlings resulting from crosses between larger statured, cold hardy cultivars Red Prince and White Prince and the less cold-hardy, dwarf cultivar Minuet at the HRC. Bailey Nurseries has signed testing agreements to evaluate 15 selections from these populations. We are currently evaluating over 700 seedlings resulting from crosses between our initial F1 selections and the dwarf cultivar Minuet (w/ Steve McNamara, Debbie Lonnee, and Jonathan Pedersen, Bailey Nurseries, Inc.). We signed an exclusive license agreement with Bailey Nurseries, Inc. to market and sell the Betty Matthews clone of Kentucky Wisteria. Plant sales are expected to begin no later than 2011. New plantings of seedlings populations of Lacebark elm (Ulmus parvifolia) and Bald cypress (Taxodium distichum) were established at Grand Rapids in 2007 for cold hardiness evaluation. Cornelian cherry (Cornus mas) and sweetgum (Liquidambar styraciflua) populations established at Grand Rapids in 2005 suffered extensive cold damage with the sweetgums being completely killed-off. Approximately ten Cornelian cherry genotypes which suffered little to no damage are being vegetatively propagated for futher testing. A full years data on a planting of 650 Ribes aureum var. villosum (Clove Currant) seedlings, derived from 13 maternal parents established in May, 2006 at the Horticultural Research Center has been collected. The species, native to the upper Great Plains, is noted for its early season display of bright yellow, clove-scented flowers. We have identified families with a propensity for early flowering, disease resistance, and repeat bloom. Individual plants have been noted for these traits. At least one more year of data will be collected before selections are made for parental and cultivar potential. Efforts continue to identify and characterize black spot resistance genes in Rosa germplasm. Three tetraploid (cultivated) rose populations have been phenotyped for black spot resistance. Two of these populations are currently being evaluated with bulk segregant analysis in order to identify markers more closely linked to the resistance genes. Marker development for the BSA analysis was based on resistance gene analog sequences developed in collaboration with Dr. Thomas Debener at the University of Hannover in Germany. Tetraploid and diploid populations segregating for partial resistance to the three races of black spot disease have been developed. They will be analyzed to determine levels of specific or general combining ability. <br /> We have secured all the rose black spot races that have been reported and cultured around the world. We have obtained rose genotypes used in these various race differentiation tests. We have designed a new host differential array amalgamated from members of the previous tests. We will be running the races across the new array to standardize our current understanding of the rose black spot race situation in the world. The information will allow for a more concerted effort in black spot resistance gene identification and mapping efforts. With some recently obtained grant funding, we have initiated a study of the epidemiology of the fungal pathogen Cryptodiaporthe canker. This pathogen incites the golden canker disease in Pagoda dogwood (Cornus alternifolia). The disease is the primary limiting factor to Pagoda dogwood gaining significance in the upper Midwest Landscape Nursery industry. We have collected canker samples from several diseased Pagoda dogwood trees in Minnesota and have cultured the fungus. Spore trapping and rotating uninfected disease-free trees under infected trees through the growing season (April-October) should provide critical information on the spore dispersal cycle, infection timing, and disease development. Results should allow for the development of best management practices for the nursery industry. We also intend to develope a high-throughput screening protocol for identification of resistant germplasm (w/ Jenny Juzwik, USDA Forestry/Plant Pathology, Bob Blanchette, Plant Path., Kathy Zuzek). We have concluded experiments designed to determine the cause of stunting, necrosis, and distorted growth exhibited by river birches growing in artificial growing media. These symptoms showed-up as we attempted to screen birch germplasm for elevated pH tolerance. Experiments to determine the cause have included insect exclusion, manipulation of soil types, investigations into the role of soil microorganisms, and the role of various micro- and macronutrients. Interestingly, similar symptoms have been detected in pecan orchards, where symptoms are alleviated with Ni treatments. Mineral soils and Ni treatments alleviated the BAGS symptoms in our experiments (w/ Steve McNamara, Carl Rosen, Soil Sciences). With funding obtained from the Minnesota Nursery Landscape Association we have been collecting data and setting-up experiments designed to determine the relative invasiveness of introduced maple species (in comparison to native maples) and elucidate life history and reproductive biology traits which contribute to invasiveness. This is the second season in which we have made flower and seed counts for one to three genotypes of seven Acer species. Seed has been collected and tested for viability for each of these genotypes. Seed lots for each have been put into several storage regimes to test for dormancy requirments and viability. Seed is being sown in seven landscape environments to test for invasive potential. Long-term experiments are planned to evaluate persistence in different environments and reproductive success of these plants (w/ Steve McNamara). With some grant funding we have initiated a germplasm evaluation of some woody plant species with potential as sources of cellulosic derived ethanol. Alnus or alder species are nitrogen-fixing woody plants capable of growing on water saturated soils and nutrient poor soils which have never been used for food production. If alders capable of growing on such soils were found to produce ethanol profitably, they should be of some benefit to society. Finding key collaborators, Ulrike Tschirner  Bioproducts, Andy David  Forest Products, and Dean Current  CINRAM, was the key to obtaining the funding that is allowing us to pursue this research. We have established 4 of 6 proposed research sites this year. Our graduate student is evaluating mature wood samples of several Alnus, Salix, and Populus species for wood structure and ethanol yield. We hope to establish a correlation between yields in younger seedlings in the test plots and mature samples(w/ Ulrike Tschirner, Will Kusch, BioProducts/Andy David, Forest Products/Dean Current, CINRAM).<br /> <br /> Rolston St. Hilaire - New Mexico State University. Accomplishments: Micropropagated bigtooth maple (Acer grandidentatum) plants and tested their responses to short term radiation stress (Ph.D. Clare Bowen-OConnor, 2008). Evaluated the genetic diversity among selected provenances of bigtooth maples using simple sequence markers (sabbatical in the USDA-ARS lab in Beltsville, Maryland, 2007). Completed the evaluation of water use of contrasting designed landscapes used in urban desert environments (M.S. student, Victoria Frietze). Started the evaluation of weatherbased irrigation controllers (Ph.D student, Malik Aljouni). Developing a methodology for categorizing urban landscape types (Ph.D student, Malik Aljouni). Evaluating the impacts of climate change on selected New Mexico crops (Ph.D student, Salman Al Kofahi).<br /> <br /> Roger Kjelgren - Utah State University. Accomplishments: Working with nursery industry in the Intermountain West on developing pot-in-pot system for production of native plants. Looking at expanding to small farm/organic growers to add pot-in-pot native production of slower growing native woody species on contract basis.<br /> <br /> Jim Sellmer - Penn State University. Accomplishments: Pennsylvania researchers have developed a screening method for challenging Tusga species for susceptibility to hemlock woolly adelgid (HWA). Employing the challenge, they have confirmed the resistance of Tsuga chinensis (Chinese hemlock). Results of that research have been accepted for publication in the Journal of Arboriculture and Urban Forestry. A similar challenge protocol has been employed in evaluation of elongate hemlock scale (EHS) on hemlock. Preliminary data suggests that the system works for other scale insects. White pine weevil management research has demonstrated initial success in attracting and trapping adults using an alpha-pinene lure over that of a conventional alcohol/gum turpentine evaporative lure during a year in low white pine weevil presence/pressure.<br /> <br /> Janet Cole  Oklahoma State University. Accomplishments: Research on control of anthracnose caused by Colletotrichum gloeosporioides on Euonymus fortunei has been ongoing for several years. This research has shown that most fungicides are not effective in controlling anthracnose symptoms, but mancozeb reduces symptoms. Better control has been achieved by changing crop management practices. Plants grown under shade have less anthracnose symptoms than plants grown in full sun. Plants sprinkler irrigated during the afternoon generally have less symptoms that those that are sprinkler irrigated in the morning.<br /> <br /> Hannah Mathers  Ohio State University. Accomplishments: A multi-state survey of the United States (US) nursery/ landscape industry, worth $147.8 billion (Bn), generating 1.9 million (Mn) jobs and having an annual payroll of over three billion dollars was conducted in 2006-07 to gather information such as labor use, demographics and employment characteristics previously not collected. The lack of information was unpredicted considering over 40% of production costs and 20 to 39% of gross sales go to labor, and labor shortages, immigration reform and legal status of employees are widely reported as the US nursery/ landscape industry=s most critical issues. A total of 4466, self administered questionnaires (SAQs) containing 31 questions and 139 variables were sent in the summer of 2006, to nurseries [large (20 acres or more) and 15 medium (5 to 19 acres), i.e. 16.5 employees/ site] in each of nine states, Ohio, Michigan, Delaware, Tennessee, Florida, Indiana, Kentucky, Arizona and Rhode Island and 1548 SAQs were returned and analyzed (34%). Hispanics constituted 70% of nursery workforce, 57% from Mexico, and were the dominant group in all states except Indiana. The average employee age was 18-34, 41.7% had completed high school, 75% earned $6 to 10/ hr, 70% lacked health insurance and labor retention was less than 50% after five. For a long time, industry felt that split bark was an environmental problem, driven mainly by cold temperatures. But we were receiving reports of split bark in warmer parts of the country, such as Georgia, the Carolinas and California. Why would it be a cold issue if split bark is happening in those areas? Winter temperatures are part of the problem, but only because glyphosate weakens the bark structure enough to cause the trunks to split under stress. There's a large body of national research that supports those findings. Our research on the role of glyphosate and bark cracking has resulted in our teaming up with agricultural company, Monsanto, to help develop a glyphosate product that is safer to use for weed control around landscape and nursery woody plants. Dr. Mathers at OSU has been leading national public research on the impacts of glyphosate on woody plants, as well as educational efforts on which glyphosate products to use and how to properly apply the chemical in nursery/landscape settings.<br /> <br /> Gary Kling - University of Illinois. Accomplishments: Finished up a joint research project with Hannah Mathers with the publication of a joint article (see below). This project was a direct result of cooperation facilitated by our participation in the WERA-058. Finished the first phase of a research project on planting depth on Green ash, White ash, Thornless common honeylocust and Norway maple in which liners were planted at three depths (root flare at grade, root flare 6 or 12 below grade) and the trees grown for 2 years in a high quality nursery soil. At the end of 2 years, planting depth produced no differences in root dry mass within each species. Increasing depth however, resulted in increased trunk caliper for White ash and Norway maple. Quality ratings of the root systems (a function of number and branching) decreased for the deepest planted White ash but was unchanged in the other species. Norway maple had a decreasing root density with increasing depth and the deepest trees had roots that altered their original direction, turning to grow upward toward the surface. Additional replications of these treatments have remained in the ground and have now been grown a total of 5 seasons  data to be collected fall of 2008, followed by transplanting to landscape sites. <br /> <br /> Chris Starbuck - University of Missouri. Accomplishments: Research in collaboration with Dan Struve, Hannah Mathers, Bob Tripepi and others has documented that trees and shrubs of a number of species can be successfully transplanted bare root in summer using the Missouri Gravel Bed method. Recent work has shown that adding calcined clay to the gravel root growth medium improves plant growth in the gravel bed relative to the original mix containing 10% sand. Incorporating calcined clay also reduces the frequency of fertilization and irrigation required to maintain plants in the bed in good condition. <br /> <br /> Art Cameron - Department of Horticulture Michigan State University. Accomplishments: We conducted research on new crops including tender and hardy herbaceous and woody perennials. We determined photoperiod and vernalization requirements for several species and cultivars including Aquilegia Winky, Astilbe Astary Mix, Campanula Merrybells, Coreopsis Jethro Tull, Helianthus Table Mountain, Heliopsi Tuscan Sun and Lupinus Gallery Blue. Specific studies were also conducted on several selections of Coreopsis. We have continued studies on select tropical plants grown as summer annuals in Michigan including several cultivars of Colocasia, Musa and Xanthosomas. We have investigated vernalization and short day substitution for vernalization in Coreopsis Sunray. We concluded and published several studies on vernalization of Veronica Red Fox, Laruentia Beths Blue, and Dianthus Baths Pink.Several trade publications on new crop development were written and published.

Publications

Klett, J. E. 2007. 2006 Annual Winners. ColoGreen 23(1) 59-60.<br /> <br /> Klett, J. E. 2007. Plant Select® for 2007. ColoGreen 23(2) 64-65.<br /> <br /> Klett, J. E. 2007. Superior Herbaceous Perennials. ColoGreen 23(3) 52-54.<br /> <br /> Klett, J. E. 2007. Container Weed Control. ColoGreen 23(4) 48-49.<br /> <br /> Klett, J. E. 2007. The Root of the Matter. ColoGreen 23(5) 54-55.<br /> <br /> Klett, J. E. 2007. Plant Select® Update. ColoGreen 23(6) 50-51.<br /> <br /> Klett, J. E., Litus, Gl., And Ounsworth, M. 2007. Woody Plant Drought Study. Looseleaf 24(1) 16.<br /> <br /> Klett, J. E. 2007. More Unusual Woody Plants from Research Plots. Looseleaf 24(2) 10-11.<br /> <br /> Klett, J. E. 2007. Superior Herbaceous Perennials from Research Plots. Looseleaf 24(3) 10-11.<br /> <br /> Ounsworth, M. and Klett, J. E. 2007. The Root of the Matter. Looseleaf 24(4) 8.<br /> <br /> Klett, J. E. 2007. 2008 Plant Select®. Looseleaf 24(5) 12-13.<br /> <br /> Klett, J. E. 2007 Best 2007 Annual Flower Trials. Looseleaf 24(6) 6-7.<br /> <br /> Klett, J. E., Staats, D., and Brescher. 2007. Colorado State University 2007 Annual Flower Trial Garden Performance Report. 207p.<br /> <br /> Klett, J. E., Staats, D., Howlett, T., and Rogoyski, M. 2008. Weed Control and Phytotoxicity Following Pre-emergence Herbicide Applications to Container-grown Herbaceous Plants. J. Environ. Hort. 26(1) 39-44.<br /> <br /> Klett, J. E. and MacDonald. 2007. Multi-site Woody Plant Evaluation in Colorado. Hort. Science 42(4) 995. (Abstract)<br /> <br /> Howlett, T., Staats, D., and Klett, J. E. 2007. Efficacy and Phytotoxicity of Pre-emergence Herbicides in Container-grown Landscape Plants. Hort Science 42(4) 877. (Abstract)<br /> <br /> Peterson, B.J., W.R. Graves, and J. Sharma. 2008. Color of pubescence on bud scales conflicts with taxonomic keys for identifying species of Dirca L. Thymelaeaceae). Rhodora: in press.<br /> <br /> Graves, W.R. 2008. Habitat and reproduction of Dirca mexicana. Rhodora: in press.<br /> <br /> Sharma, J., J.A. Schrader, and W.R. Graves. 2008. Ecology and phenotypic variation of Leitneria floridana (Leitneriaceae) in disjunct native habitats. Castanea: in press.<br /> <br /> Schrader, J.A. and W.R. Graves. 2008. Nodulation and growth of Alnus nitida and Alnus maritima inoculated with species-specific and nonspecific Frankia. Journal of Environmental Horticulture 26:29-34.<br /> <br /> Schrader, J.A., M.A. Kroggel, and W.R. Graves. 2007. Nodulation and nitrogen-fixing capacity of rhizobial isolates from China in symbiosis with Maackia amurensis. Journal of Environmental Horticulture 25:47-50.<br /> <br /> Mickelbart, M.V.*, G.S. Bender, G.W. Witney, C. Adams, and M.L. Arpaia. 2007. Effect of clonal rootstocks on Hass avocado yield components, alternate bearing, and nutrition. Journal of Horticultural Science and Biotechnology 82:460-466.<br /> <br /> Mickelbart, M.V.*, S. Melser, and M.L. Arpaia. 2007. Salinity-induced changes in ion concentrations of Hass avocado trees on three rootstocks. Journal of Plant Nutrition 30:105-122.<br /> <br /> Teixeira, E.I.*, D.J. Moot, and M.V. Mickelbart. 2007. Seasonal patterns of root C and N reserves of lucerne crops (Medicago sativa L.) grown in a temperate climate were affected by defoliation regime. European Journal of Agronomy 26:10-20.<br /> <br /> Mickelbart, M.V.*, S. Larsen, R. Heath, and M.L. Arpaia. 2007. Changes in photosynthesis during flush development in avocado (Persea Americana Mill.). HortScience 42(4):992.<br /> <br /> Mickelbart, M.V.*, N. Wasmer, S. Revankar, and L. Collier-Christian. 2007. Effects of supplemental sulfur on growth of three woody ornamental species. HortScience 42(4):994.<br /> <br /> Yoo, C.Y.*, J.B. Jin, K. Miura, Y. Hua, M. Gosney, M.V. Mickelbart, R.A. Bressan, and P.M. Hasegawa. 2007. Ca2+/CaM signaling through AtGTL1 mediates drought stress adaptation. Plant Physiology, Plant Biology 07, Final Program and Abstract Supplement p. 108.<br /> <br /> Sharma, J., J.A. Schrader, and W.R. Graves. 2008. Ecology and phenotypic variation of Leitneria floridana (Leitneriaceae) in disjunct native habitats. Castanea. In Press. <br /> <br /> Peterson, B.J., W.R. Graves, and J. Sharma. 2008. Color of pubescence on bud scales conflicts with taxonomic keys for identifying species of Dirca L. (Thymelaeaceae). Rhodora: in press.<br /> Funderburk, J.E, L.A. Mound, and J.Sharma. 2007. Thysanoptera associated with native, terrestrial orchids in northern Florida and southern Georgia. Journal of Entomological Science 42(4):573-581.<br /> <br /> Sharma, J., Ishida, M.L.***, and V.L. Yadon. 2007. Mycorrhizal diversity of an endemic terrestrial orchid. Lankesteriana 7(1-2): 215-218.<br /> <br /> Sharma, J. and A. Bolques. 2007. Nutrient profile of runoff water at commercial plant nurseries in southeastern U.S. Proceedings of Southern Nursery Association Research Conference 52:29-33. <br /> <br /> Sharma, J., P.C. Wilson, and T.H. Yeager. 2008. Remediation of Runoff: Options for Container Plant Nurseries. 8pp. ENH-1088, Institute of Food and Agricultural Sciences, University of Florida. <br /> <br /> Sharma, J., A.V. Ogram, and A. Al-Agely. 2007. Mycorrhizae: Implications for Environmental Remediation and Resource Conservation. 5pp. ENH-1086, Institute of Food and Agricultural Sciences, University of Florida. <br /> <br /> Funderburk, J.E., S. Diffie, J. Sharma, A. Hodges, and L.S. Osborne. 2007. Thrips of ornamentals in the southeastern US. Gainesville, Florida: University of Florida, EDIS. 6 pp. ENY-845, Institute of Food and Agricultural Sciences, University of Florida. <br /> <br /> Sharma, J. 2008. Why Worry About Runoff at Container Plant Nurseries: Part II. 18 February.<br /> <br /> Sharma, J. 2007. Why Worry About Runoff at Container Plant Nurseries: Part I. 9(13). 10 September.<br /> <br /> Byrne, D.H., N. Anderson, and H.B. Pemberton. 2007. The use of Rosa wichuraiana in the development of landscape roses adapted to hot humid climates. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae 751:267-274.<br /> <br /> Pemberton, H.B. and U.K. Schuch. 2007. Relationship between visually determined starch content and flowering of containerized field-grown garden roses. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae 751:105-109.<br /> <br /> Shupert, D., D.H. Byrne, and H.B. Pemberton. 2007. Inheritance of flower traits, leaflet number, and prickles in roses. Fourth International Symposium on Rose Research and Cultivation. Acta Horticulturae 751:331-335.<br /> <br /> Pemberton, H.B., editor. 2007. Proceedings of the fourth international symposium on rose research and cultivation. Acta Horticulturae 751. International Society for Horticultural Science. Leuven, Belgium. 512 pages.<br /> <br /> Mackay, W.A., H.B. Pemberton, J. Maxim, and S. Pillai. 2008. Ionizing irradiation using electron beam to control importation of biothreat agents in geranium cuttings inhibits rooting. HortScience 43(3):955-956.<br /> <br /> Pemberton, H.B. 2008. An alternative method for analyzing landscape performance rating data. HortScience 43(4):1295 (Abstr.).<br /> <br /> Whitaker, V.M., K. Zuzek, and S.C. Hokanson. 2007. Resistance of 12 rose genotypes to 14 isolates of Diplocarpon rosae Wolf (rose blackspot) collected from eastern North America. Plant Breeding 126:83-88.<br /> <br /> Whitaker, V.M., J.M. Bradeen, and S.C. Hokanson. 2007. Distribution of rose blackspot (Diplocarpon rosae Wolf) genetic diversity in eastern North America using AFLP and implications for resistance screening Journal of the American Society for Horticultural Science 132:534-540.<br /> <br /> Whitaker, V.M., K. Zuzek, J.M. Bradeen, and S.C. Hokanson. 2007. Culturing and long-term storage of virulent races of the rose blackspot pathogen Diplocarpon rosae Wolf. Acta Horticulturae 751:199-205.<br /> <br /> Zuzek, K. and S.C. Hokanson. 2007. Shrub rose breeding at the University of Minnesota. Acta Horticulturae 751:291-298.<br /> <br /> Zlesak, D., K. Zuzek, and S.C. Hokanson. 2007. Rose pollen viability over time at varying storage temperatures. Acta Horticulturae 751:337-343.<br /> <br /> Khalil, S.D., R. St. Hilaire, M. OConnell and J. Mexal. 200x. Horticulturists can grow moonshine yarrow on a limited moisture budget. J. Environ. Hort. In Press.<br /> <br /> Bsoul, E., R. St. Hilaire, and D. VanLeeuwen. 2007. Bigtooth maples from selected provenances effectively endure deficit irrigation. Hortscience: 42:1167-1173.<br /> <br /> Bowen-OConnor, C.A., R. St. Hilaire, J. Hubstenberger, C.A. Baca, and D.M. VanLeeuwen. 2007. In vitro propagation of Acer grandidentatum Nutt. 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Impact Statements

1. Results show the potential for developing container production and over-wintering systems for northern nurseries that will save hundreds of thousands of dollars and make container production a viable enterprise for more local growers. Before this information is disseminated for adoption by growers, however, it needs to be confirmed under varying conditions through several New England winters.
2. Received a patent for the first cultivar of Alnus maritima (September Sun)
3. Assisted growers and extension agents with nursery runoff, orchid management and preservation, and native plant propagation by conducting workshops and lectures throughout Florida, in other states, and in Canada. Consulted with state and federal agencies to provide information on conservation of North American orchids.
4. Anthracnose caused by Colletotrichum gloeosporioides on Euonymus fortunei causes millions of dollars in losses for producers due to crop losses or reduced crop quality. One Oklahoma grower estimated that annual crop losses amounted to about $200,000 annually, but by changing their management practices, they were able to drastically reduce crop losses, while also reducing pesticide use. They estimate that their reduction in pesticide usage was reduced by $46,000 in product and labor expenses by growing plants under shade and changing irrigation practices. An intangible benefit of these changes was that labor and dollars allocated to pesticide purchase could be diverted to other crops, thus also improving quality of other crops as well.
5. The economic cost to the U.S. nursery industry from bark cracking is conservatively estimated at $6.6 million a year. Thats roughly 2.5 percent of finished inventory. Add to that the conservative estimate of $14 million in landscape tree failures, and weve got a national phenomenon that has been happening for several years but only now are people taking seriously.
6. These results indicate that in the production nursery setting, we can demonstrate increased tree performance with increasing planting depth for coarsely-rooted species such as ash and honeylocust and detrimental effects for Norway maple (a species with a finer root system). The long term effects of performance in the landscape  good or bad- will take additional time to determine.
7. There is increasing interest in the gravel bed as a tool to allow growers, landscapers, arborists and city parks professionals to take advantage of the cost benefits associated with bare root nursery stock while avoiding the limitation in planting season associated with conventional bare root handling. Refinements based on recent research results will simplify establishment and management of gravel beds, making this method more appealing to potential users.
8. New crops can have an immediate impact on the profitability of Greenhouse and Nursery Industries. Also, efficient production techniques can help reduce energy cost per plant produced and increased the amount of plants that can be grown over the course of a season. Past successes include Laurentia cv Beths Blue (named after a graduate student in our program) and novel production systems for containerized Hostas. New production of ornamental grasses accounts for a significant rise in production space. Introduction of new crops is critical for maintenance of a healthy floriculture industry in Michigan.

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