Vol. 14, No. 2 MANAGING FRUIT TREES Spring 1996 TOPICS & INSTRUCTORS: Wednesday, April 17, 9 a.m. to 3 p.m. Center for Urban Horticulture & Area Home Orchard $35, fee includes lunch; pre-registration required; pro- gram limited to 30 participants This program earns 2 WSDA Pesticide Recertification Credits and 5 CEU's under the ISA Certification Program. PROGRAM OVERVIEW: Building upon the Plant Health Care principles introduced previously, this program will address fruit tree management in the urban landscape. TOPICS & INSTRUCTORS: FRUIT TREE SELECTION & CULTURE Gary Moulton, Scientific Assistant, WSU-Mt. Vernon Re- arch Unit, will review the selection and cultural require - ents of a variety of common fruits, including apples, cherries, plums, and nectarines. Understanding plant needs relative to site conditions and design goals will allow for proper selection and placement of plants in the landscape. SYSTEMATIC APPROACH TO PEST DIAGNOSIS IN FRUIT TREES Dr. Ralph Byther, Emeritus Professor of Plant Pathology, WSU-Puyallup, reviews common and not-so-common pest problems of fruit trees. A demonstration of a systematic approach to diagnosis will be presented. Ralph and Gary will then lead an intensive field diagnosis practice session in a local home orchard. IPM strategies will be discussed. You may bring specimens for diagnosis or discussion. RHODODENDRON & AZALEA SELECTION & CULTURE Dr. Ray Maleike, Extension Horticulturist, WSU-Puyallup, and Scott Vergara, Consulting Horticulturist & Instructor, will review the cultural requirements of rhododendrons and azaleas. Understanding plant needs relative to site conditions will allow for proper selection and placement of plants in the landscape. SYSTEMATIC APPROACH TO PEST DIAGNOSIS IN RHODODENDRONS & AZALEAS Scott Vergara and Ray Maleike continue with reviews of common and not-so-common pest problems of rhododendrons and azaleas. A demonstration of a systematic approach to diagnosis will be presented. Participant classroom work will be followed by field diagnosis practice in the Arboretum collections. 1PM strategies will be discussed. You may bring specimens for diagnosis or discussion. MANAGING ANNUALS, PERENNIALS & BULBS Wednesday, June 26, 9 a.m. to 3 p.m. Bellevue Botanical Garden Visitors Center $35, fee includes lunch; pre-registration required; pro- gram limited to 30 participants This program earns 2 WSDA Pesticide Recertification Credits. MANAGING RHODODENDRONS & AZALEAS Wednesday, May 8, 9 a.m. to 3 p.m. Washington Park Arboretum Graham Visitors Center $35, fee includes lunch; pre-registration required; pro- gram limited to 30 participants This program earns 2 WSDA Pesticide Recertification Credits 5 CEU’s under the ISA Certification Program. PROGRAM OVERVIEW: Continuing to build upon our Plant Health Care principles, this seminar will address rhododendron & azalea management in the urban landscape. PROGRAM OVERVIEW: We will use our Plant Health Care principles to address the management of herbaceous materials in the urban landscape. TOPICS & INSTRUCTORS: ANNUAL, PERENNIAL & BULB SELECTION & CULTURE Carrie Becker, Landscape Designer/Consultant and Instructor, Edmonds Community College, will review the cultural require- ments of perennials, annuals and bulbs. Understanding plant needs relative to site conditions and design goals will allow for proper selection and placement of plants in the landscape. -continues on next page- SYSTEMATIC APPROACH TO PEST DIAGNOSIS IN ANNUALS, PERENNIALS & BULBS Mary Robson, WSU Area Extension Horticulturist, and Dr. Susan Miller, WSU Extension IPM Specialist, review common and not-so-common pest problems of these herbaceous materials. A demonstration of a systematic approach to diagnosis will be presented. Participant classroom work will be followed by field diagnosis practice in the Bellevue Botanical Gardens. IPM strategies will be discussed. You may bring specimens for diagnosis or discussion. OTHER EDUCATIONAL OPPORTUNITIES EDMONDS COMMUNITY COLLEGE SPRING COURSES: Spring Plant ID: Plant Diseases: Landscape Studies; Greenhouse Studies; Annuals, Bulbs & Ferns; Advanced Propagation; Mixed Border Practicum; Landscape Design II; Drip Irrigation. Evening classes will include: Intro to Horticulture; Spring Plant ID; Turf Industry; Construction Concrete; Bidding & Estimating; Weed ID & Management; Turf; Landscape Renovation. For registration information, call (206) 640-1679. SOUTH SEATTLE COMMUNITY COLLEGE SPRING COURSES: Retail Floristry; Intro to Design; Garden Center; Spring Plant ID: Spring Maintenance; Turfgrass; Small Business Management; Landscape Design; Advanced Tree Pruning; Pest ID: Principles of Horticulture; Tree Selection; Floral Design. To register, call (206) 764-5394. LAKE WASHINGTON TECHNICAL COLLEGE SPRING COURSES: Irrigation Design & Management; Pruning and Landscape Renovation; Spring Plant ID; Mysteri- ous Life of Plants. Call (206) 828-5600 for more information. WASHINGTON STATE NURSERY & LANDSCAPE ASSOCIATION SPRING SEMINARS: Taking the WCN/ WCL Test-Preview, March 12, $25 members, $35 non- members; WCN/WCL Testing, March 26; Seminar: Personal & Business Financial Management. March 27, instructed by Kirk Mills, $20 members, $30 non-members; Seminar: Plant Disease Identification & Control, April 23, instructed by Kathleen Day, $45 members, $55 non-members. Call WSNLA at (206) 863-4482 for additional information. ProHort Seminars are planned and conducted cooperatively by the UW Center for Urban Horticulture and the WSU Cooperative Extension-King County Horticulture Program. PROHORT BOOKSHELF by Valerie Easton, CUH Horticultural Librarian Hours are Mondays, 9 a.m. to 7:45 p.m., Tuesdays through Fridays, 9 a.m. to 5 p.m., except holidays. Phone; (206) 685- 8033 for further information. Miller Library (and CUH) will be closed Monday, May 27. New titles of interest: Creating and Managing Woodlands Around Towns , by Simon J. Hodge. Forestry Commission Handbook; v.l 1. London: HMSO, 1995. Diseases of Annuals and Perennials: A Ball Guide , by Ann Renee Chase, Margery Daughtrey and Gary W. Simone. Batavia, IL: Ball Publishing, 1995. Gardening with Water, by James van Sweden and Wolfgang Oehme. lsted. New York: Random House, 1995. Habitat Conservation Planning: Endangered Species and Urban Growth, by Timothy Beatley. 1st ed. Austin: Univer- sity of Texas Press, 1994. Mazes , by Adrian Fisher and Diana Kingham. Princes Risborough: Shire Publications, 199 1 . ^ Natural Insect Control: The Ecological Gardener’ s Guide to ^ Foiling Pests , by Warren Schultz. Handbook #139. Brooklyn, NY: Brooklyn Botanic Garden, 1994. Picturing Plants: An Analytical History of Botanical Illustra- tion. by Gill Saunders. London: Zwemmer, 1995. Plants and their Names: A Concise Dictionary, by Roger Hyams and R. Pankhurst. Oxford: Oxford University Press, 1995. The Private Life of Plants: A Natural Histoiy of Plant Behav- ior. by David Attenborough. Princeton, NJ: Princeton University Press, 1995. Recognition Manual of Landscape Plants Used Commonly in the Pacific Northwest, by Clement W. Hamilton. Seattle: Center for Urban Horticulture, 1995. Restoring Wetlands in Washington: A Guidebook for Wetland Restoration, Planning and Implementation, by Michelle L. Stevens and Ron Vanbianchi. Olympia: Washington State Dept, of Ecology, 1993. Trees for Architecture and Landscape, by Robert L. Zion. 2nd ed. New York: Van Nostrand Reinhold, 1995. Vines & Wines in A Small Garden: From Planting to Bottling " by James Page-Roberts. London: Herbert Press, 1995. (ABSTRACT THINKING: Current ^Research Abstracts of Interest for Your Review THE EFFECT OF WOOD MULCH TYPE AND DEPTH ON WEED AND TREE GROWTH AND CERTAIN SOIL PARAMETERS Compiled by Dave Stockdale Abstracts reprinted here were selected to represent the broad variety of topics of interest to our readership and are not necessarily intended as endorsements of the research or researchers cited. We strongly suggest that you read the complete articles to fully evaluate the merits of the information provided relative to possible applications to your work situation. All journals cited are available at the Miller Library at CUH. HAZARD TREE ASSESSMENTS: DEVELOPING A SPECIES PROFILE FOR WESTERN HEMLOCK Julian A. Dunster. Journal of Arboriculture 22(1):5 1 -57. January, 1996. Many new housing developments are moving into forests and the public and political pressures to retain trees are high. However, in the absence of good species profiles, hazard tree and tree retention assessments in such forests are fraught with problems. To overcome some of these, species profiles are being developed to assist arborists in knowing what is reasonable to retain and why, and to provide a more defensible basis to justify removal. The hemlock has been evaluated in detail. The findings reveal that external indicators are not sufficient to to judge the internal condition of hemlocks. A preliminary species profile has been developed for the western h emlock and is now being refined. Katrina M. Greenly and Donald A. Rakow. Journal of Arboriculture 21(5):225-232. September, 1995. The use of wood byproducts as horticultural mulch has increased in the last decade as the horticulture industries and landscape architects have raised the public’s awareness of the aesthetic and maintenance benefits to be gained from mulch use. The objectives of this experiment were to evaluate the effect that two types (chipped pine and shredded hardwood chips) and three depths (7.5 cm, 15 cm, and 25 cm) of mulch and an unmulched control would have upon: 1 ) oxygen %, moisture % and soil temperatures; 2) growth of two thin barked trees (Pinus strobus and Quercus palustris); 3) establishment of weed populations; and 4) potential change in certain soil parameters (pH. nitrates, and soluble salts). After two years, no differences were found between mulch types, but soil oxygen levels declined (non- significantly). temperatures declined, and moisture levels increased with increasing depth of mulch. Weed density and diversity also declined with increasing mulch depth. For both, stem growth was greater with the 7.5 cm depth of mulch than with other depths or the control. Soil pH, nitrates, and salt levels were unaffected. VALIDATION OF A TREE FAILURE EVALUATION SYSTEM PROHORT Seminar Registration MANAGING FRUITTREES $35.00 MANAGING RHODODENDRONS & AZALEAS $35.00 MANAGING ANNUALS & BULBS $35.00 Yes, I require a vegetarian meal (where applicable) TOTAL: $ Group Rates: five or more persons, less 20%. Group registrations must be accompanied by ONE check or purchase order at least one week in advance. Portion of fees may cover refreshments and speaker expense. Make checks payable to the University of Washington; receipts available at the door. Mail payment and registration to: Center for Urban Horticul- ture/ProHort, University of Washington, Box 3541 1 5, Seattle, WA 981 95-41 15. For information, call 685-8033. Name / Company Name Address City State Zip Day Phone Evening Phone To request disability accommodation contact the Office of the ADA Coordinator, at least ten days in advance of an event: 543-6450 (voice) 543-6452 (TDD); 685-3885 (FAX) access@u. washington.edu (email) Gary W. Hickman, Ed Perry, and Richard Evans. Journal of Arboriculture 21(5): September, 1995. In 1987. 695 oak trees, Quercus lobata and Q. w’izlizenii, were evaluated using a nine-compo- nent rating system. In 1 994, the trees were reevaluated to validate the original system in predicting tree failure. Analysis of the results showed that 3 components (decline/vigor, trunk condition and lean) correctly predicted subse- quent tree failure or survival. Decline, a relative measure of leaf cover and color, was the most important factor in predicting total tree failure. TURF HERBICIDE INJURY TO LANDSCAPE TREES AS INFLUENCED BY MULCH L.J. Smith and W.A. Skroch. Journal of Environmental Horticulture 13(2):60-63. June, 1995. A two year field study was conducted in 1991 and 1992 to evaluate the sensitivity of landscape trees to certain turf herbicides as affected by mulch. The study included four tree species (‘Bradford’ callery pear, crape myrtle. Eastern redbud, red maple), four mulch treatments (shredded hardwood bark, pine bark, pine needles, no mulch), and six herbicide treatments [Banvel (dicamba), BAS 514 OOH (quinclorac), Image (imazaquin), Redeem (triclopyr), Stinger (clopyralid)]. Herbicides were applied as directed sprays at the labeled rates for use on turf. Visual injury (%) ratings were measured at 30, 60, 90, 120, and 150 days after treatment (DAT). Trunk diameters and total plant fresh weights were measured at the conclusion of the study. In most cases, applying the herbicide over mulch decreased tree injury compared to applications to bare soil. Red maples were most severely injured by Stinger (clopyralid) (27%) (60 DAT) and BAS 514 OOH (quinclorac) (33%) (60 DAT). Redbuds were most severely injured by the same two herbicides, but at 89% (120 DAT) and 73% (120 DAT), respectively. ‘Bradford’ pears were injured by Banvel (dicamba) (32%) (120 DAT), and crape myrtles by Image (imazaquin) (10%) (120 DAT). LANDSCAPE INSTALLATION FIRMS: SOURCE OF PLANT MATERIAL M.P. Garber and K. Bondari. Journal of Environmental Horticulture 13(l):35-39. March, 1995. The plant material purchasing patterns of landscape installers, which could help nurserymen develop marketing plans for this College of Forest Resources Center for Urban Horticulture University of Washington Box 354115 Seattle, WA 98195-4115 09-9615-122 SPRING 1996 important segment of the green industry are identified in this study. Landscape installers revealed that approximately 97% of Georgia landscape installation firms purchased plants in- state and. in-state purchases were 73% of all plant material purchases. Most firms (91%) purchased directly from growers and obtained the largest percentage of plant material from this source (59.4%). The most important factors in selection of the production nursery where plants were purchased, as judged by the percent response for very important were plant quality (85.3%), availability of plant material in desired sizes (62.7%) and, availability of plant varieties (60%). The quality of eight categories of plants grown in Georgia, relative to other states, was favorable. Landscape installers expected to purchase the same or greater quantities of plants over the next five years. The top three plant material trends likely to affect the type of plants purchased by landscape installers were decreased water availability (23.7%), increased demand for low maintenance landscapes (21.4%) and increased use of native or stress tolerant plants (17.6%). Across all size firms, the two most frequently listed opportunities for plant producers to help installers were improved size and quality standards, and awareness of plant material specified by landscape architects so requested material is available. The results varied by size of firm and provide insight for development of marketing plans for growers serving the landscape installation industry. NONPROFIT ORG. U.S. POSTAGE PAID Seattle, Wash. PERMIT NO. 62