Here’s an outdoor project for you to do right now. Master Gardener Gene Frye provides helpful hints about pruning your trees and shrubs. Late winter/early spring is the optimum time for cleaning up and shaping up. (Plus, think of the exercise you’ll get before it’s really hot and humidJ)
THE BASICS OF PRUNING WOODY PLANTS
Proper pruning is an important and often neglected step in caring for woody plants, mainly trees and shrubs.
The main objectives of pruning woody plants are to control their size and shape, to correct defects in the plant’s structure and to repair storm or animal damage.
WHAT TO PRUNE?
One of the highest priority items to prune is narrow-angled crotches, for they are mechanically weak and subject to rot, hence they are vulnerable to storm damage. Another category is branches that are dead, broken or diseased, for they are traditional entry points for rot to get started. Finally, misplaced branches should be pruned out.
WHEN TO PRUNE?
For most woody plants, late winter to early spring is the best time to prune, for the pruning wounds are exposed to the weather for a minimum amount of time before healing starts to take place. A major exception is that spring-flowering shrubs should be pruned just after the blooms fade In order to avoid destroying flower buds. Do not prune late in the growing season, for then the new growth that results may not have sufficient time to harden off before it gets cold. This results in stressing the plant to the point where it may not survive the winter. It is important to avoid pruning oaks between mid-March and late September to minimize the chance of Oak Wilt disease being introduced to the tree.
HOW TO PRUNE?
· Use the correct tools – regular pruning saws but no carpenter or bow saws.
· Do not make cuts flush with the trunk. Instead make the cut just outside of the branch collar. (See Extension Publication SUL 5 for more specific directions.)
· Do not use wound dressings except when pruning oaks during the growing season.
· Do not remove more than one third of the plant tissues in any one year.
· The chances of rot getting started increase rapidly for wounds over three inches in diameter.
· Extension Publication SUL 5, “Pruning Trees and Shrubs”
· ISU Extension Publication Pm 1958, “Pruning Ornamental Shrubs”
· Extension Publication SUL 6, “Managing Storm Damaged Trees”
· ISU Extension Publication RG 104, “Horticulture Publications”