March 2, 2005
Woodbury Bulletin
Betsy Halden

We can feel the warmth of the sun. We can hear birds singing. The air almost smells like early spring. Are you ready to be outside in your yard? Would you like to start with a late winter – early spring chore? Consider pruning your trees and shrubs.

In order to provide an attractive setting for our homes, landscapes need to be maintained. One of the primary chores in keeping up the landscape is pruning. Good pruning involves selectively removing branches to strengthen plant structure and improve appearance. Proper pruning promotes the health and prolongs the life of trees and shrubs. Improper pruning destroys their natural beauty, may weaken them and lead to their premature death.

Late February through March is an excellent time to prune most trees and shrubs when they are still dormant. Deciduous trees - those which lose leaves in fall - are best pruned before they leaf out. You can get a clear view of the structure and you can select and remove appropriate branches. Pruning wounds heal faster at this time of year, just prior to when new growth begins. Trees with free-flowing sap in late winter - such as maple, birch, walnut, butternut - may lose sap through the pruning cuts, but that won’t hurt a healthy tree. It is not necessary to apply a wound dressing to a pruning cut.

The only reason not to prune spring flowering shrubs in late winter is the pruning would remove the emerging spring blooms. This would affect plants such as forsythia, lilac, azalea, and rhododendron. Prune these plants immediately after they have bloomed later in the spring.

“Don’t prune oak trees during April, May, or June.” Research has shown that oak wilt may be more easily transmitted during those months.

I talked about pruning recently with Vera Wagner, Woodbury resident and University of Minnesota Extension Service Washington County Master Gardener and Tree Care Advisor. Vera teaches classes on pruning. Here are some tips she shared:

“Be sure your tools are sharp and clean. Use the right tool for the right job. As the diameter of the branch or stem increases so should the size of your pruning tool. Don’t try to cut anything larger than ¾” with a hand pruner. Use a by-pass pruner on small live branches, moving up to a lopper or hand saw as needed. Hedge shears are intended for hedges. If you need to reach a tall branch use a pole pruner.

“Never prune near electrical or utility wires. Call your utility company to do the job. If you have a large project or you need to climb a ladder or reach above your shoulders, it is best to call an International Society of Certified Arborists (ISA) professional.

“Know the plant you are pruning. Understand what it is supposed to look like as well as its intended use in the landscape. Know the species, its characteristics, the growth habit and its natural form.

When you are pruning, it is essential to make proper cuts. Do not make flush cuts. Flush cuts are cuts made as close as possible to the trunk or main branch. Flush cuts produce large wounds, destroy the tree’s natural functions that promote healing, and slow the healing process. When pruning trees, make the final cut beyond the branch collar and branch bark ridge. The branch collar is the swollen area at the base of the branch. The branch bark ridge is the dark, rough bark ridge that separates the branch from the main branch or trunk. Pruning just beyond the branch collar and branch bark ridge retains the tree’s natural defense mechanisms and promotes the healing process. When a branch is pruned properly, a slightly raised area remains on the trunk or main branch. Avoid leaving stubs.

Here are two websites for additional information on pruning: www.mnstac.org and www.isa-msa.org

Betsy Halden can be reached at eahalden@comcast.net.