Looking ahead to the time when we can get to the trees in our yards, the late dormant period (February to early April) is a great time to prune deciduous trees. The absence of foliage at this time of year gives the home gardener a clear view of the tree and allows them to select and remove appropriate branches. This will also give everyone a chance to prune out the storm-damaged limbs and branches. Then you can evaluate the future existence of some of the more heavily damaged trees.
Another advantage of pruning in this late dormant timeframe is the "healing" process occurs more rapidly just prior to the onset of growth in spring. Proper pruning improves the appearance, maintains the health, and prolongs the life of trees. Improper pruning destroys their natural beauty, weakens them, and may lead to their premature death.
It is essential to make proper cuts when pruning trees. Do not make flush cuts which are cuts made as close as possible to the trunk or main branch. Flush cuts produce large wounds, destroy the tree's natural mechanisms that promote healing, and slow the healing process. When pruning trees, make the final cut just 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. However, do not leave stubs.
Don't apply wound dressings to pruning cuts. The application of wound dressings or paints doesn't stop decay and may actually inhibit or delay the healing of wounds. There is one exception to the no paint recommendation and that involves oak trees. To reduce the risk of the spread of oak wilt, don't prune oaks from April 1 to July 1. If you must prune oaks during this time period, for example to correct storm damage, apply a light-colored latex paint to all cut surfaces.
Use the 3-cut procedure when cutting large branches, this will prevent extensive bark damage. Make the first cut about 1 to 2 feet from the main branch or trunk. Cut upward and go about halfway through the branch. Make the second cut a few inches beyond the first. Cut downward completely through the branch. Make the final cut just beyond the branch collar.
Some trees, such as maple, birch, and elm, bleed heavily when pruned in late winter or early spring. However, the heavy bleeding doesn't harm the trees and they won't bleed to death. Eventually the flow of sap will slow and stop. Heavy bleeding of susceptible trees can be avoided by pruning in late June or early July.
The pruning of deciduous trees by the home gardener should be limited to small trees and the removal of smaller branches that can be reached from the ground in medium to large trees. Branches high up in large trees and those near utility lines should be left to professional arborists. Professional arborists will have the proper training and equipment to safely perform the job.
We have many publications on pruning trees here at our office. Stop by and ask a question or pick up a publication. You can always call our Hortline at 515-294-3108, for any lawn, garden and landscape plant question. Our Extension Office is located at 209 Centennial Dr., Suite A, Cherokee, Iowa. The phone number is 712-225-6196.