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					J. Environ. Hort. 27(1):1–6. March 2009


       Evaluation of Clay Aggregates in Perennial
                 Offshoot Production1
    Jeremy M. Pickens2, Glenn B. Fain3, Jeff L. Sibley4, Charles H. Gilliam4, and John W. Olive5
                          Department of Horticulture, 101 Funchess Hall
                                  Auburn University, AL 36849

                                                  Abstract
  In an effort to compare yield and time required to remove substrate from roots of liners, Ophiopogon japonicus
  and Ophiopogon japonicus ‘Nana’ (lilyturf) bare root bibs were potted into 100% aged pine bark, 8:2 (v:v) pine
  bark:peat moss, 100% perlite, 100% fine grade Profile™ porous ceramic (Profile™ products LLC, Buffalo
  Grove, IL), or 100% course grade Profile™ porous ceramic. In a second study Ophiopogon japonicus was potted
  into 100% aged pine bark, 100% 3/16-inch HydRocks® (Big River Industries Alpharetta, GA), fine grade 100%
  Profile™, 100% perlite, 100% sand, 8:2 (v:v) pine bark:peat moss, and 3:1 (v:v) 3/16 HydRocks®:sand. In the
  second study, fine grade Profile™ produced the highest number of total bibs per container and bib production
  was similar to 8:2 pine bark:peat moss. HydRocks® was similar to pine bark in total bibs per container but was
  more efficiently removed from roots. Removal of the HydRocks® substrate from plant roots required 50% less
  time than removal of pine bark:peat moss substrate and 51% less time than removal of pine bark substrate.
  HydRocks® took 23% less time to remove from roots than fine grade Profile™. Results indicate that clay
  materials such as HydRocks® and Profile™, when compared to conventional substrates can provide suitable
  yields while also decreasing labor cost by decreasing time to bare-root.
  Index words: Profile™, HydRocks®, bibs, lightweight aggregate.
  Species used in this study: lilyturf (Ophiopogon japonicus (Thumb.) Ker-Gawl.; Ophiopogon japonicus
  ‘Nana’.
J. Environ. Hort. 27(1):7–11. March 2009


  Pruning Roots Affects Tree Quality in Container-
                   Grown Oaks1
                               Edward F. Gilman2, C. Harchick and C. Wiese
                                  Environmental Horticulture Department
                                   University of Florida, Gainesville, FL

                                                    Abstract
  Height and trunk growth of Quercus virginiana ‘SDLN’ Cathedral Oak® tops was not affected by root pruning
  that occurred each time trees were potted into a larger container, beginning when rooted cuttings were planted
  into #3 containers. All trees produced in air root-pruning Accelerator® containers without mechanical root
  pruning produced enough circling roots to make them culls according to Florida and California standards for
  nursery stock. Removing root defects by pruning roots when trees are potted to the next larger size reduced culls
  from 100% to 40% of the crop and is recommended for quality tree production. Root pruning when trees were
  potted from one container size to the next size had no influence on the number of primary structural roots that
  grew directly from the trunk base. Root pruning had no impact on the number of roots that were deflected down.
  Waiting to root prune until #3 containers were potted into #15 containers did not increase the number of straight
  roots compared to non-pruned controls. Slicing the root ball edges vertically from top to bottom in several places
  appears to reduce circling roots capable of forming stem girdling roots. But slicing in the manner described in
  this study did little to reduce the descending root defects.
  Index words: circling roots, root defects, adventitious roots, stem-girdling roots, root flare, trunk flare, root
  number, nursery stock quality, air root-pruning containers.
  Species used in this study: Cathedral Oak® (Quercus virginiana Mill. ‘SNDL’ Cathedral Oak®).
J. Environ. Hort. 27(1):12–16. March 2009


     Propagation of Selected Clones of Eastern
   Redbud (Cercis canadensis) by Stem Cuttings1
                    John M. Wooldridge2, Frank A. Blazich3, and Stuart L. Warren4
                                 Department of Horticultural Science
                                   North Carolina State University
                                      Raleigh, NC 27695-7609

                                                   Abstract
  Two experiments, one utilizing softwood cuttings and the other semi-hardwood cuttings, were conducted to
  investigate the influence of growth stage and auxin treatment on rooting four related clones of eastern redbud
  (Cercis canadensis L.). The four clones were ‘Flame’ (C. canadensis L. ‘Flame’), dwarf white, and two
  selections (NC99-6-1 and NC99-6-2) of an F1 generation derived from a cross of ‘Flame’ and dwarf white. At
  each growth stage, rooting responses of the clones varied and were influenced greatly by auxin treatment,
  demonstrating the variable rooting potential of the genotypes. In both studies, ‘Flame’ rooted well [63% rooting
  in the softwood study when treated with the potassium (K) salt (K-salt) of indolebutyric acid (IBA) at 5000
  mg·L–1 (ppm), 83% rooting when treated in the semi-hardwood study with K-IBA at 10,000 mg·L–1], indicating
  stem cuttings may be a commercially feasible means of propagation for ‘Flame.’ Softwood cuttings of dwarf
  white (46%) and NC99-6-2 (75%) rooted best when treated with K-IBA at 15,000 mg·L–1, whereas softwood
  cuttings of NC99-6-1 rooted best (46%) when treated with K-IBA at 10,000 mg·L–1. Dwarf white and the F1s
  rooted poorly in the semi-hardwood study.
  Index words: adventitious rooting, auxin, K-indolebutyric acid, Fabaceae.
  Species used in this study: eastern redbud (Cercis canadensis L.).
J. Environ. Hort. 27(1):17–23. March 2009


   Evaluation of Systemic Insecticides for Potato
   Leafhopper Control in Field-Grown Red Maple1
       J.B. Oliver2, D.C. Fare3, N. Youssef4, M.A. Halcomb5, M.E. Reding6, and C.M. Ranger7
                Tennessee State University, School of Agriculture and Consumer Sciences
                     Otis L. Floyd Nursery Research Center, McMinnville, TN 37110

                                                     Abstract
  Systemic insecticides and application methods were evaluated in two trials that began in 2005 and 2006 for
  control of potato leafhopper (Empoasca fabae [Harris]) on four red maple (Acer rubrum L.) cultivars and rated
  annually through 2007. Treatments evaluated in this study included surface drenches of imidacloprid plus
  cyfluthrin (Discus) or imidacloprid plus bifenthrin (Allectus SC), clothianidin (Arena 50WDG), dinotefuran
  (Safari 20SG), or thiamethoxam (Flagship 25WG); soil inserted treatments of imidacloprid formulated as an
  experimental tablet or as an experimental gel; or a plant root dip of Discus + Terra-Sorb hydrogel. In the 2005
  trial, a one-time drench of Discus or two imidacloprid tablets significantly reduced leafhopper damage to red
  maple for a 3-year period. In the 2006 trial, a one-time drench of Allectus, Discus, Arena, Flagship, and Safari
  significantly reduced leafhopper damage for 2 years. In most cases, the Discus drench and root dip treatments
  were initially more effective than the imidacloprid tablets or the gel treatment. However, in general, the efficacy
  of imidacloprid tablet or gel treatments increased in subsequent years. Two imidacloprid tablets were more
  effective than one. Likewise, higher imidacloprid drench rates were more effective than lower rates. Most
  insecticide treatments significantly increased red maple trunk diameter, although this effect varied with cultivar
  and time. Allectus and Discus drench treatments significantly increased the branch and internode length of
  ‘Franksred’ maple in the 2005 trial. Results of this study indicate long-term potato leafhopper control with
  systemic insecticides and enhanced growth in red maple.
  Index words: leafhopper, Empoasca fabae, Acer rubrum, neonicotinoid, insecticide, tree growth.
  Species used in this study: red maple (Acer rubrum L.) cultivars ‘Autumn Flame’, ‘Fairview Flame’,
  ‘Franksred’, and ‘October Glory’.
  Chemicals used in this study: experimental imidacloprid tablet formulation (currently marketed as CoreTect);
  experimental imidacloprid gel formulation; imidacloprid + cyfluthrin (Discus); imidacloprid + bifenthrin
  (Allectus SC); clothianidin (Arena); dinotefuran (Safari); thiamethoxam (Flagship); potassium polyacrylamide
  acrylate copolymer (Terra-Sorb Fine Hydrogel).
J. Environ. Hort. 27(1):24–30. March 2009


 Impact of Improved Landscape Quality and Tree Cover
         on the Price of Single-Family Homes1
                                   Andrea Stigarll and Emmett Elam2
                            Department of Agricultural and Applied Economics
                     301 Ag. Sciences Bldg., Texas Tech University, Lubbock, TX 79409

                                                    Abstract
  Impacts of the quality of landscaping and percentage of tree cover on home prices were estimated from a sample
  of 75 home sales within the Melonie Park neighborhood in Lubbock, TX, from 2003 to 2005. Estimates were
  derived using a regression of house sale price on house characteristics, landscape quality, and tree cover. Homes
  that improved landscaping from average quality to good or excellent quality increased selling price by 5.7 and
  10.8%, respectively. Approximately 30% of the increase in sale value was accounted for by added tree cover.
  The results show that each $1.00 invested in upgrading an average landscape to excellent quality returns $1.35 in
  added property value.
  Index words: hedonic model, home prices, landscape investment, landscape quality, tree cover.
J. Environ. Hort. 27(1):31–36. March 2009


    Flowering, Fecundity, Seed Germination, and
   Seed Viability of Viburnum opulus L. Cultivars1
                                 Janine R. Conklin2 and James C. Sellmer3
                                        Department of Horticulture
                                       Pennsylvania State University
                                         University Park, PA 16802

                                                    Abstract
  Mature specimens of Viburnum opulus and cultivars ‘Leonard’s Dwarf’ and ‘Roseum’ were assessed over 2
  years for flower and seed production, seed germination, and seed viability as determined by a tetrazolium test to
  understand their invasive potential. ‘Aureum’, ‘Compactum’, ‘Losely’s Compact’, ‘Nanum’, and
  ‘Xanthocarpum’ were also tested for germination and viability of seeds. Cultivars differed in flower and seed
  production, seed germination, and seed viability. ‘Roseum’ prolifically produced highly viable seed that
  germinated at moderate rates under greenhouse conditions (8,354, 100%, and 73%, respectively). Viburnum
  opulus and ‘Leonard’s Dwarf’ produced fewer viable seed which showed moderate to low germination rates
  (609, 100%, and 53%; 712, 100%, and 5%, respectively). ‘Aureum’ and ‘Xanthocarpum’ seeds germinated at
  moderate rates (55 and 25%, respectively) and were highly viable (100%). ‘Compactum’, ‘Losely’s Compact’,
  and ‘Nanum’ germinated at low rates or failed to germinate (0, 0, and 5%, respectively), yet seeds were
  moderately viable (37, 65, and 55%, respectively). Seeds of all cultivars germinated at low rates or failed to
  germinate at both outdoor sites (0 to 5%) which suggests these plants may be weakly invasive. Short-term
  studies on biological traits such as these provide only limited information to assess the invasive potential of
  cultivars.
  Index words: European cranberrybush viburnum, invasive, greenhouse, landscape, forest, ornamentals.
  Species used in this study: European cranberrybush viburnum (Viburnum opulus L.) and cultivars ‘Aureum’,
  ‘Compactum’, ‘Leonard’s Dwarf’, ‘Losely’s Compact’, ‘Nanum’, ‘Roseum’, and ‘Xanthocarpum’.
  Chemicals used in this study: Roundup (glyphosate), N-(phosphonomethyl)glycine; Basamid (dazomet),
  Tetrahydro-3, 5-dimethyl-2H-1, 3, 5-thiadiazine-2-thione; Tetrazolium Red (TTZ), 2, 3, 5-Triphenyltetrazolium
  chloride.
J. Environ. Hort. 27(1):37–41. March 2009


     Butterfly Feeding Preferences for Four Zinnia
                       Cultivars1
                              Kenneth V. Yeargan2 and Sarah M. Colvin3
                  Department of Entomology, University of Kentucky, Lexington, KY 40546

                                                      Abstract
  Zinnias are recommended frequently for inclusion in butterfly gardens as nectar sources for adult butterflies, but
  little is known about butterfly preferences for different zinnia cultivars. We compared numbers and species of
  butterflies that visited four widely available zinnia cultivars: Zinnia violacea Cav. (formerly Zinnia elegans
  Jacq.) ‘Lilliput’, ‘Oklahoma’, ‘State Fair’, and Zinnia marylandica Spooner, Stimart, and Boyle ‘Pinwheel’.
  Mixed colors were used for all cultivars. Based on a total count of 2355 butterflies, representing 30 species,
  more than twice as many total butterflies visited ‘Lilliput’ than visited any of the other cultivars. Also, a greater
  number of butterfly species visited ‘Lilliput’ than visited any of the other cultivars. More than half of the
  counted butterflies belonged to the family Nymphalidae, with members of the families Pieridae and Hesperiidae
  being the second and third most frequent visitors, respectively.
  Index words: Lepidoptera, flower visitation, butterfly gardens.
  Species used in this study: Zinnia violacea Cav. ‘Lilliput’, ‘Oklahoma’, ‘State Fair’, and Zinnia marylandica
  Spooner, Stimart, and Boyle ‘Pinwheel’.
J. Environ. Hort. 27(1):41–50. March 2009


   Performance of Mycorrhizal Products Marketed
           for Woody Landscape Plants1
                     P. Eric Wiseman2, Kristen H. Colvin3, and Christina E. Wells4
                    Department of Horticulture, Clemson University, Clemson, SC 29634

                                                    Abstract
  Commercial products containing propagules of arbuscular mycorrhizal fungi (AMF) are widely marketed to
  improve woody plant performance in the landscape. However, the infectivity of these products has rarely been
  subjected to independent testing. We evaluated commercial AMF inoculants in a series of greenhouse
  experiments using corn (Zea mays), sorghum (Sorghum bicolor), trident maple (Acer buergerianum), and
  sweetbay magnolia (Magnolia virginiana) as host plants. In corn and sorghum, colonization rarely exceeded 5%
  when plants were treated with commercial inoculants. In contrast, viable lab-cultured inoculant of similar species
  composition yielded mean colonization percentages of 38 to 61%. Despite the near absence of colonization,
  commercial inoculants generally improved shoot growth and increased soil nutrient concentrations in a dose-
  dependent manner. Commercial inoculants had no effect on mycorrhizal colonization or shoot growth of trident
  maple or sweetbay magnolia liners. Product-treated magnolias grown from seed also developed little or no
  mycorrhizal colonization, whereas plants treated with a lab-cultured inoculant were 74% colonized. If
  commercial AMF inoculants are to receive broad acceptance as landscape soil amendments, manufacturers must
  demonstrate that their products can promote mycorrhizal colonization under the conditions of their intended
  distribution and use.
  Index words: corn (Zea mays), sorghum (Sorghum bicolor), trident maple (Acer buergerianum), sweetbay
  magnolia (Magnolia virginiana), mycorrhizal colonization, arbuscular mycorrhizal fungi.
J. Environ. Hort. 27(1):51–55. March 2009


   Preemergence Control of Black Cottonwood in
              Nursery Containers1
                                            James E. Altland2
                             Application Technology Research Unit, USDA-ARS
                                  1680 Madison Ave., Wooster, OH 44691

                                                   Abstract
  Two experiments were conducted to evaluate preemergence herbicides for control of black cottonwood (Populus
  trichocarpa) in nursery containers. In 2006, granular preemergence herbicides were applied to recently filled,
  weed-free containers in May just prior to seed release from mature cottonwood trees. Flumioxazin provided the
  most effective cottonwood control, although control with isoxaben + trifluralin, oxyfluorfen + oryzalin, and
  pendimethalin was also effective. In 2007, containers were filled February 15, and herbicides were applied to
  separate groups of containers on February 22, March 14, April 16, and May 15. Containers were over-seeded
  with cottonwood for a 2-week period starting on May 16. Control with most herbicides improved as the date of
  application neared the date of seeding. Flumioxazin provided the most effective control throughout the
  experiment, but control from it also improved as the date of application neared the time of seeding.
  Index words: woody weed species, poplar, weed control.
  Herbicides used in this study: Ornamental Herbicide II (OH2, pendimethalin + oxyfluorfen), N-(1-
  ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine            +         2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-
  (trifluoromethyl)benzene; Rout (oryzalin + oxyfluorfen), 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide + 2-
  chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene; Snapshot 2.5TG (isoxaben + trifluralin), N-[3-
  (1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide           +           2,6-dinitro-N,N-dipropyl-4-
  (trifluoromethyl)benzenamine; Pendulum 2G (pendimethalin); Ronstar G (oxadiazon), 3-[2,4-dichloro-5-(1-
  methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one; BroadStar (flumioxazin), 2-[7-fluoro-
  3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H)-dione;
  Regal O-O (oxadiazon + oxyfluorfen); RegalKade (prodiamine), 2,4 dinitro-N3,N3-dipropyl-6-(trifluoromethyl)-
  1,3-benzenediamine; RegalStar (oxadiazon + prodiamine).
  Species used in this study: black cottonwood (Populus trichocarpa).
J. Environ. Hort. 27(1):56–62. March 2009


     Production of Woody Nursery Crops in Clean
              Chip Residual Substrate1
Cheryl R. Boyer2, Charles H. Gilliam3, Glenn B. Fain4, Thomas V. Gallagher5, H. Allen Torbert6, and
                                           Jeff L. Sibley3
             Department of Horticulture, 101 Funchess Hall, Auburn University, AL 36849

                                                    Abstract
  Clean chip residual (CCR) is a potential replacement for pine bark (PB) in nursery crop substrates. It is a by-
  product of in-field forestry harvesting practices and has been shown to produce annual plants and perennials
  similar in size to plants grown in PB. Studies were conducted in two locations, Auburn, AL, and Poplarville,
  MS, to evaluate growth of woody ornamentals grown in CCR or PB. Five species were tested; Loropetalum
  chinensis var. rubrum, Buddleja davidii ‘Black Knight’, Lagerstroemia indica ‘Hopi’, Lagerstroemia × fauriei
  ‘Natchez’, and Rhododendron indicum ‘Mrs. G.G. Gerbing’. There were few differences in plant growth indices,
  leaf chlorophyll content, and inflorescence number over the course of the year for all species at both sites.
  Percent rootball coverage was generally similar among treatments, though those grown in PB had the greatest
  percent rootball coverage for loropetalum and buddleja (at both sites) and azalea at Auburn. Shoot dry weight of
  loropetalum and crapemytrle grown in PB at Poplarville was greater than plants grown in CCR.
  Index words: media, forest residuals, pine, loblolly, peat moss, pine bark, sustainable, alternative, loropetalum,
  crapemyrtle, azalea, buddleja.
  Species used in this study: Loropetalum (Loropetalum chinensis var. rubrum R. Br.); buddleja (Buddleja
  davidii ‘Black Knight’ Franch.); crapemyrtle (Lagerstroemia indica L. ‘Hopi’ and Lagerstroemia × fauriei
  ‘Natchez’ Wallich ex Paxt.); azalea (Rhododendron indicum ‘Mrs. G.G. Gerbing’).

				
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