9 * A Center for Urban Horticulture University of Washington Vol. 4, No. 4 Cooperative Extension Washington State University Fall 1986 LANDSCAPE MAINTENANCE SEMINARS . . . for the landscape professional Cooperating: Center for Urban Horticul- ture, University of Washington; Cooper- ative Extension Service, Washington State University; Edmonds Community College; South Seattle Community College. Small Business Legalities and Liabilities: What Every Landscaper Should Know! Date : Monday, October 20 Time : 9:00 a.m.-noon Location : Center for Urban Horticulture Instructor : Austin Farrell What’s it like to be sued? How can you avoid being sued? Why is it important to have things in writing? What should a con- tract include? Should you incorporate? What are your potential liabilities? These questions and more will be answered in this seminar. Ample time will be allowed for discussing your individual legal and insur- ance questions. Mr. Farrell is an attorney with the legal firm of Farrell & Cool P.S. He has dealt exten- sively with the legal concerns of landscape business people. Winterizing the Landscape Date : Wednesday, November 19 Time : 9:00 a.m.-noon Location : Center for Urban Horticulture Instructors : Dr. Ray Maleike and Dr. Rita L. Hummel Last year’s early cold snap caught us and our plants by surprise. This seminar will help you better understand the factors af- fecting plant hardiness, the various ways in which cold weather can damage plants, and practical steps you can take to protect plants from winter damage. Find out how mulches, late summer fertilization, and irri- gation practices affect a plant’s susceptibility to winter injury. And what about anti- transpirants — are they safe and effective? Dr. Maleike is extension horticulturist and Dr. Hummel is assistant horticulturist at Washington State University’s Western Washington Research and Extension Cen- ter in Puyallup. Successful Landscape Maintenance Estimating Date : Wednesday, December 10 Time : 9:00 a.m.-noon Location : Center for Urban Horticulture Instructor : Bruce McCormack Develop confidence in your ability to prop- erly estimate landscape maintenance jobs. Learn how to price your services at a mar- ketable rate and how to make money at what you are doing. Know that you are doing the right thing for your financial situa- tion. Bruce McCormack is president of Blue Rib- bon Landscape Management and a past president of the Washington State Nur- serymen’s Association. He also has taught landscape business courses at Edmonds Community College. OTHER EDUCATIONAL OPPORTUNITIES Tree Evaluation Workshop. The Center for Urban Horticulture will sponsor a tree evaluation workshop at the Washington Park Arboretum on Wednesday, November 5, 8:30 a. m. -4:00 p.m. The course is in- tended for anyone who is required to pro- vide tree evaluations in connection with tree loss, retention of trees, or liability concerns. Through both classroom instruction and field exercises, participants will learn how to make objective, accurate, dollar-value ap- praisals based upon a tree’s condition and appropriateness of location. Those attend- ing should be familiar with basic appraisal techniques. The following panel of experts will lead the workshop: Molly Beck, con- sulting arborist, Northwest Arborvitae, Bothell; Dr. James R. Clark, professor, Cen- ter for Urban Horticulture; Robert Mazany, consulting arborist, Tree and Landscape Consulting Services Ltd., Portland, Ore- gon; and Sandra Thorne-Brown, urban for- ester, Thorne-Brown & Associates, Belle- vue. For registration information call 545-8033. From Nature Into Landscape — Plants from Winter-Rain Regions. This fall se- ries will feature an in-depth look at plants from winter-rain regions of the world (Medi- terranean, Chile, California, Western Aus- tralia, South Africa) that are grown in the Washington Park Arboretum. Emphasis will be placed on the connection between a plant’s natural habitat and its landscape util- ity. Saturdays, October 25, November 1, and November 8, 9:00 a.m.-noon, at the Arboretum. Preregistration is required, $15/series or $7. 50/individual session. WALP Annual Convention. The Wash- ington Association of Landscape Profes- sionals will hold its annual convention, which includes educational programs and a landscape awards program, on November 21 and 22 at the Doubletree Plaza Hotel, Tukwila. Entry deadline for the WALP En- vironmental Awards Program is September 27. Call Peggy Farrell, 232-7825. Myths in Tree Care — The Root of the Problem. The International Society of Ar- boriculture, Pacific Northwest Chapter, will hold its annual meeting and training con- ference on October 1, 2, and 3 in Corvallis, Oregon. “Myths in Tree Care” is the theme of this year’s program. Call J.B. Good, Inc., (503) 752-6260. Edmonds Community College Horti- culture Courses — Fall 1986. Day courses: Hand Tools and Small Machines for Horticulture; Broadleaf Plant I.D.; Houseplant I.D.; Design Layout; Land- scape Materials; Greenhouse Studies. Eve- ning courses: Hand Tools and Small Ma- chines for Horticulture; Urban Trees; Insect Pests; Broadleaf Plant I.D.; Greenhouse Management; Sprinkler Design. Call 771-1679. South Seattle Community College Horticulture Courses — Fall 1986. The Landscape Industry; Fall Plant I.D.; Hor- ticultural Drafting; Fall Landscape Mainte- nance; Horticultural Science; Washington Certified Nurserymen’s Review; Tree Prun- ing and Repair; Insect I.D. and Control; Plant Propagation; Introduction to Drain- age and Irrigation; Landscape Design II; Small Business Management for Horticul- ture; Landscape Maintenance Estimating and Bidding. Call 764-5336. Lake Washington Vocational Tech- nical Institute. Training is offered in nur- sery and greenhouse operations. Call Don Marshall, 828-5621 or 828-3311. ARTICLES Mycorrhizae and Drought Tolerance Dr. Barbara Smit-Spinks Center for Urban Horticulture University of Washington Much of the research on the importance of mycorrhizae for tree establishment and growth has been directed toward commer- cial tree production (orchards, forestry), but the research also has implications for the management of urban trees. Mycorrhizae are a beneficial association of roots and fungi which can alter the structure, nutrient concentration, growth regulator chemistry, water use, and photosynthesis of plants. There are two common types of mycor- rhizae: (1) ectomycorrhizae, in which the fungus develops outside of the root cells; and (2) endomycorrhizae, in which the site of infection is inside the cells. Ectomycor- rhizae occur on trees such as pine, larch, fir, spruce, oak, birch, and hickory. They can be seen on the roots and often change the root structure by inhibiting root hair forma- tion and causing root branching. Endo- mycorrhizae occur on many herbaceous plants as well as Russian olive, maple, ash, honeysuckle, and apple. This type of my- corrhizae causes little or no change in the physical appearance of the roots. Enhanced drought tolerance of plants with mycorrhizal roots was the initial indicator of the beneficial nature of this plant/fungus relationship. Our lab and others are in- volved in research examining the mecha- nism by which mycorrhizae impart in- creased drought tolerance to plants. Cooperative projects are under way with researchers from the College of Forest Re- sources and Washington State University’s Western Washington Research and Exten- sion Center. We are studying the effects of mycorrhizae on water uptake through the root systems of Dougas fir (ectomycor- rhizae) and crab apple (endomycorrhizae). Mark Coleman, a Ph.D. candidate, has looked at the relationship between phos- phorous nutrition and water uptake of Douglas fir and how they are affected by mycorrhizal infection. There are three possible direct mechanisms by which the fungus could alter the water status of roots: (1) increased root area for the collection of water; (2) increased transport of water to the root by fungal hyphae in the soil; and (3) reduced drying out of the root due to the mantle of fungus covering the root. We are, however, particularly inter- ested in the effects of the mycorrhizae on the capacity of a root to transport water from the soil to the shoot. This charac- teristic, root hydraulic conductance, can be affected by changes in plant nutrition and plant hormones as well as by other factors. If root hydraulic conductance is increased in mycorrhizal roots, the increased drought tolerance of a plant could be independent of the soil volume available to explore for water. This would be important for plants with restricted soil volume, including con- tainer grown plants. We are hopeful that this research will indi- cate whether mycorrhizal associations might be advantageous for urban trees in low water/low maintenance sites. Further research will be necessary to determine the cultural techniques needed to inoculate and maintain mycorrhizal associations under ur- ban conditions. Urban Trees — What Makes a Good Street Tree? Dr. James R. Clark Center for Urban Horticulture University of Washington The search for the perfect urban tree is never ending. Anyone who deals with street tree programs or other urban landscape sit- uations desires an aesthetically pleasing, easy-to-cultivate, pest-free, stress-tolerant, environmentally functional, fast-growing plant. Whether such a plant will ever be found is open to question. It is clear, though, that the trees currently being used in cities are compromise choices, upon which we are constantly trying to improve. One approach to identifying species that will perform well as street trees is to examine the characteristics of those trees that have already proven successful. Do species and cultivars frequently used in cities possess certain features that could be used as in- dicators of success? In 1978, Jim Kielbaso and Ken Ottman of Michigan State University compiled lists of the most popular street trees in the U.S. From these lists I have selected nine species appropriate for the Pacific Northwest region and compared four ecological/cultural characteristics — shade tolerance, flood tol- erance, tolerance of poor soil, and ease of transplanting (Table 1). The following refer- ences were consulted for ecological/cultural information: Fowells, H. 1965. Silvics of Forest Trees of the United States. U.S. Dept, of Agriculture Handbook 271. Harris, R. 1983. Arboriculture — Care of Trees, Shrubs and Vines in the Land- scape. Englewood Cliffs, N.J.: Pren- tice-Hall, Inc. Himelick, E. 1981. Tree and Shrub Trans- planting Manual. Urbana, IL.: Inter- national Society of Arboriculture. The popular street trees vary widely in their tolerance to shade. Although nursery trees are grown under “full-sun” conditions, the amount of light that may reach street level in Table 1 Relative Tolerance: Ease of Species Shade Flooding Poor Soils Transplanting Norway Maple Acer platanoides Tol. ? ? Easy Red Maple A. rubrum Tol. High High Easy Sugar Maple A. saccharum Very Tol. Low Low Mod. Green Ash Fraxinus pennsyluanica Intermed. High High Easy Honey Locust Gleditsia triacanthos inermis Intol. High Mod. Very Easy Sweetgum Liquidambar styraciflua Intol. High Mod. Difficult Pin Oak Quercus palustris Intol. High High Very Easy Red Oak Q. rubra Intermed. Mod. ? Mod. Easy Little-Leaf Linden Tilia cordata ? ? Mod. Easy Source: Fowells 1965, Harris 1983, Himelick 1981, Kielbaso and Ottman 1978. Registration Form: Landscape Maintenance Seminars Complete Series: Legalities, Winterizing, Estimating $30.00 Individual Seminars Small Business Legalities and Liabilities $12.50 Winterizing the Landscape $12.50 Successful Landscape Maintenance Estimating $12.50 TOTAL: $ Group Rates: Firms/institutions sending two or more employees per seminar. The rates are: 2-5 employees $10. 00/person 6 or more employees $ 9.00/person To qualify for group rates: (1) firm’s registration must be received at least one week in advance; (2) all registrants must be from the same firm; and (3) total registration fee must be paid with one check or purchase order. Firms using purchase orders must make prior registration arrangements. Make checks payable to the University of Washington; no bank cards. Receipts will not be returned by mail; they will be available at the door. NAME ADDRESS CITY STATE ZIP PHONE (DAY) PHONE (EVE) Mail payment and registration to: Urban Horticulture Program, University of Wash- ington, GF-15, Seattle, WA 98195 For more information please call 545-8033. a high-rise urban core is but a fraction of “full-sun. ” Tall buildings cast large shadows that can shade trees for much of the day. In Seattle, my students and I have studied the performance of sweetgum over a range of planting sites. Growth, branching pattern, and leaf development vary widely within a few blocks. We believe the amount of light these trees receive is an important factor contributing to this variation. Shade-intol- erant species will not perform well under heavy shade. Thus, in an urban location surrounded by skyscrapers, a street tree should be tolerant of shade. Successful street trees are generally tolerant of poor soil and/or flooded conditions. This is not at all surprising considering the typical urban soils — highly compacted and with poor structure and low fertility. It does re- veal that one strategy for selection is to iden- tify those species that will grow on heavy, poorly drained soils. The performance of sugar maple seems to support this point. Though it has been widely planted as a street tree, sugar maple has a low tolerance of flooding and poor soils and only seems to perform well in well- drained locations. My observation is that it is not a good urban tree. Finally, good street trees should be easy to transplant. Since the level of aftercare is generally minimal, transplanted street trees must quickly establish themselves. All the trees listed in Table 1 are fairly easy to trans- plant except sweetgum. Marvin Black, Seattle city arborist, has said that this spe- cies “struggles” for a couple of years after planting but then does quite well. Are there other plants with a similar transplant diffi- culty that would make good street trees with better aftercare? The search for the perfect urban tree will continue, probably without success. But an awareness of the characteristics found in most successful urban trees will enhance our chances of identifying new plant mate- rial for the urban landscape. The Franklin Tree — A Plant with a History Dr. Ray Maleike Western Washington Research and Extension Center Washington State University The Franklin tree, or Franklinia alatamaha, previously has been listed as Gordonia al- atamaha, and the latter scientific name is still occasionally used in the trade. The Franklin tree could be classified as a large shrub or small tree. It usually is branched quite low or may have two or three main trunks. Ultimate height is be- tween 20 and 30 ft. (7-10 m) with a width of about V2 —3A the height. The large specimen at the Washington Park Arboretum is well over 20 ft. The main branching is usually ascending with more lateral branches. The outline is a large, broad, upright oval if it is grown in the open sun. Leaves are usually limited to the end of the branches giving the tree an open, airy ap- pearance. The obovate leaves are 4-5 in. long and 1— IV2 in. wide, with weak and irregular crenations or serrations. The tops of the leaves are lustrous, a good landscape characteristic. The autumn color is bright, rich red, similar to some clones of Oxydendron arboreum. The plant should be grown in the full sun to achieve the max- imum effect of the autumn coloration. Stems are usually a gray-brown. Very often younger stems will have thin striations of a yellow-tan. This is an interesting landscape feature for close viewing in the winter. The effect is lost with algae covered stems. The 3-3V2 in. flowers are solitary with 5 white petals and many yellow stamens. The flowers are similar to single white Camellia or Stewartia flowers. Both Camellia and Franklinia belong to the Theaceae or Tea family. Blooming commences in late sum- mer or early autumn. While never prolific, the flowering is showy and may last up to 2 months. Flowering is effective during a period when there is a dearth of blooming woody plant materials. Hardiness has been reported as Zone 5 ( - 10 to - 5°F) by the Arnold Arboretum or Zone 6 ( - 10 to - 5°F), USDA. A recent journal article reported Franklinia stems killed at -25 to -27°F. Franklinia seems to be relatively pest-free. It may suffer from root rot under lack of aera- tion/poor drainage. It is best planted in a moist, well-aerated soil. Its culture is not much different than most of the Ericaceous plants. The unusual history of the plant may be a good selling point. John Bartram, a Phila- delphia plant hunter, originally found the plant growing on the banks of the Altamaha River in Georgia in 1770. Bartram failed to find the plant in subsequent trips. The plant has never been found in the wild since. Franklinia alatamaha is a multiseason inter- est landscape plant from its very good, lus- trous summer foliage to late-season bloom- ing and has excellent fall foliage coloration and good bark characteristics. Its only cultural requirement is that it have a well- drained, moist soil. CENTER FOR URBAN HORTICULTURE University of Washington, GF-15 Seattle, WA 98195 Non-Profit Org. U.S. Postage Paid Permit No. 62 Seattle, WA