- - AGRICULTURE CORE CURRICULUM - - (CLF6000) Advanced Core Cluster: ORNAMENTAL HORTICULTURE (CLF6550) Unit Title: PRUNING ____________________________________________________________________________ (CLF6557) Topic: PLANT SUPPORT Time Taught in Year(s) SYSTEMS 1 hour 3 and 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome #: (J-8) - Demonstrate two basic methods for the support of ornamentals and discuss how, when, and where supports are established, maintained, and removed. Special Materials and Equipment: Samples of stake and tie materials; plants to stake and tie. References: Editors of Ortho Books. (1989). ALL ABOUT PRUNING. Available from: Ortho Books, P.O. Box 5047, San Ramon, CA 94583. Editors of Sunset Books and Sunset Magazine. (1990). WESTERN GARDEN BOOK. Menlo Park, CA: Lane Publishing Co. Harris, Richard W. (1983). ARBORICULTURE: CARE OF TREES, SHRUBS, AND VINES IN THE LANDSCAPE. Englewood Cliffs, NJ: Prentice-Hall. Evaluation: Quiz by instructor TOPIC PRESENTATION: PLANT SUPPORT SYSTEMS A. Wire cylinders and baskets are sometimes used to support annuals and perennials. They should be anchored to the ground and should not restrict the growth of the plant. B. Trellises are structures or frames of latticework used as a screen or as a framework for climbing plants. Unlike stakes, they are intentionally permanent and are not primarily used to support a plant that cannot stand alone. C. Staking 1. Stakes are used to protect or to anchor trees and shrubs and to support young trees. 2. The extent of staking for trees depends on the following factors: a. tree strength and conformation b. expected wind conditions c. amount of vehicular and foot-traffic d. type of landscape planting e. level of follow-up maintenance 3. In order to decide whether staking is necessary, consider the following consequences of supporting a tree: a. The tree grows taller. b. There is less growth of the diameter of the trunk near the ground but more growth near the top support tie; this produces a decreased or even a reverse trunk taper. c. The tree develops a smaller root system. d. A staked tree offers more wind resistance than an unstaked tree of equal height (because the top is not free to bend). e. It is subject to rubbing and girdling from stakes and ties. f. If the tree is closely tied to only one opaque stake, the trunk will grow or bend away from the stake when the ties are removed. This is probably due to a redistribution of the growth substances (auxins) between the lighted and shaded sides of the trunk. 4. Almost every response to support staking prevents a tree from becoming strong. Moreover, staking is expensive and time consuming and often detracts from the tree's appearance. 5. Nevertheless, there are times when staking is necessary and proper staking can overcome most of the problems associated with the procedure. a. It can help young trees until they get root anchorage or their tops become strong enough to stand alone. b. Staking and other materials may be needed to protect young trees from vehicles, equipment, animals, and vandalism. 6. Types of Staking a. No staking is necessary for most shrubs and for many conifers and trees with limbs close to the ground. Their low branches keep people and equipment away from the trunk and their root systems are adequate to hold them upright. b. Protective staking is used primarily to keep mowing equipment, vehicles, and vandals away from young trees. 1) Protective stakes should be easily visible. 2) Increasingly, urban trees are being protected by heavy wire or metal grillwork surrounding their trunks. c. Anchor staking is sometimes needed to hold the roots of a tree or shrub until they can grow into the surrounding soil. 1) Two or three short stakes usually provide enough anchorage for roots. 2) Place one loop or figure-eight tie between each stake and the trunk. Each tie should be secured near the top of the stake and should permit movement at that level without allowing movement of the roots or rubbing of the trunk against the stakes. 3) The top of the plant may benefit from thinning to reduce weight and wind resistance. 4) Ties can usually be removed at the end of the first growing season; stakes can be left in place to protect the trunk. d. Support staking is needed for trees whose trunks are not strong enough to stand without support or to return upright after a wind. 1) Weak trunks are often found on trees that have been previously staked, grown close together, or had their lower branches shaded or removed. 2) Weak trunks are common on many container-grown trees. 3) Top support for these trees should be about 6 inches above the lowest level at which the trunk can be held and still return upright after the top is bent. 8. Stake and Tie Materials a. Support stakes come in a variety of materials and shapes. 1) Wooden stakes are usually sawn wood or 2-inch diameter poles; poles do not split or break as easily as sawn wood. Wooden stakes are easy to work with and low in cost. 2) Various shapes and sizes of metal stakes are also available. 3) Availability, cost, strength, durability, ease of installation, and appearance should be considered when choosing staking material. b. There are various material and methods used in tying trees to stakes. 1) Common tie materials are elastic webbing, belting, polyethylene tape, tire cording with wire ties, and wire covered with hose or tubing. Various patented ties and support devices are also available. 2) Materials NOT recommended as tie materials are rope, baling wire, covered electrical wire, string, and fishing line. 3) Any material used should contact the trunk with a broad, smooth surface and have enough elasticity to minimize trunk abrasion and girdling. 9. How to Stake a Tree a. Drive two stakes a foot from opposite sides of the trunk and in line with prevailing winds. b. Attach a firm brace between the stakes close to the ground. c. Tie tree to each stake about 6 inches above the lowest level at which the trunk can be held and still return upright after the top is bent. d. Use a flexible loop of plastic tree tie or cord. e. Tie loosely enough so that the trunk is not rigid, and can move a bit in the wind. 10. Check staked trees periodically to make sure that stakes and ties are not broken and that the tree is not being rubbed, girdled, or otherwise damaged. 11. Remove any support system that is restricting the plant's growth or that the plant has outgrown. 12. Remove the support system as soon as the plant can stand upright without it. The sooner a tree can stand alone, the sooner it will become strong. __________________________________________________________ ACTIVITY: 1. Visit a local nursery and observe staking and tying techniques used. 2. Observe trees planted in the nearest urban area and determine what kind of staking is used (support or protective) and whether or not it is effective. 3. Practice staking and tying trees obtained from the local nursery. __________________________________________________________ 1/14/91 CLH/clh #%&C