Pruning promotes health in trees, shrubs
Q. While inspecting my trees and shrubs for winter damage, I noticed some looked a little overgrown and wild. When should I plan to prune them?
A. Pruning is a practice that can help prevent many problems in plants. It helps promote plant health, and needs to be done when you notice dead or dying branches that may have been damaged by weather, disease, insects or animals. Pruning also helps stimulate new growth and will help encourage flowering. When pruning, try to follow plants' natural forms because when done properly, no one can tell they had a haircut.
Tools for your job include pruning shears, for cuts up to ¾ inches in diameter; lopping shears, for cuts up to 1 ½ inches in diameter; and hand saws which are good for larger branches.
You will want to avoid pruning shrubs such as forsythia, lilac, mock orange, honeysuckle, viburnum, red twig and yellow twig dogwood until after they flower. These plants bloom in spring on growth from the previous season. If you prune before they blossom, you will miss their flowery show. However, you should prune immediately afterward as waiting too long to snip will remove next year's flower buds.
Shrubs that flower later in summer such as potentilla, spirea, and butterfly bush bloom on growth from the current year. They should be pruned in spring. This enables the plants to bloom on new growth produced in the same season as flowering occurs. Begin by thinning out weak stems to control shape and size. If there are dead or crossing stems, cut these close to the ground.
Evergreen shrubs such as juniper, yew and mugo pine should be pruned no later than the end of April or before the appearance of new growth.
If a few stray stems appear after new growth occurs, light pruning can be done in midsummer, but avoid fall pruning of evergreens. If pruned in fall, they become more susceptible to cold injury.
If you have young trees, early spring is an ideal time to assess their health. The absence of leaves gives you a clear view of any problems needing attention. You should remove branches which cross as well as those which grow back toward the center of the tree.
Pay particular attention to any dead or diseased branches which should be removed, as well as waterspouts and suckers. Suckers are vegetative growths coming from the root system of a tree, while water sprouts are vertical vegetative growths coming from a tree's trunk or branches. Both take valuable nutrients from the tree.
It is best to leave the pruning of large established trees to qualified tree professionals who have the proper equipment. They can safely thin out branches for good spacing and prune out any diseased or damaged branches which may pose a hazard.
- Mary Moisand
• Provided by Master gardeners through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines. Call (847) 298-3502 or email northcookmg@gmail.com.