While you might think that it would harm trees and shrubs to prune them in the winter, winter is actually a very good season for tree and shrub pruning -- keep in mind that some trees don't need pruning every year and that there are best practices. There are exceptions as well, certain shrubs are best pruned after they flower because they bloom on old wood and should be pruned in early to mid summer. Learn how it helps plants to prune in winter, what to do, and what not to do.
Why Should You Prune Trees in Winter?
Pruning shrubs and trees in the winter is best because they're dormant. Since deciduous trees drop their leaves in winter, you can observe the tree's structure and prune faster than you would be able to when the tree has leafed out. Trees and shrubs are also less vulnerable to infection throughout the colder months.
One exception here may be certain flowering trees, that would be robbed of their spring buds if pruned during the winter. Shrubs that fall into this category include forsythia, dogwood, lilac, weigela, and viburnum. Instead of tree pruning in winter, wait until it has finished flowering, and then prune.
Best practice is to prune on a dry day in late winter and to sanitize pruning shears when moving from one plant to the next. This cuts down on the spread of disease in your garden.
You may enjoy reading Best Ways To Keep Your Trees Healthy This Year.
There are generally four methods as part of the winter tree pruning best practices. They include the following:
- Cleaning: Removal of dead, diseased, conflicting and/or broken parts
- Raising: Pruning to provide vertical clearance
- Reduction: Pruning to decrease height and/or spread of canopy or canopy parts
- Thinning: Selective pruning to reduce density of live branches
One of the main goals in pruning your trees is to increase the amount of light and air that pass through the crown of the tree by clearing out crowded interior branches. Look for branches that grow up or cross-over other branches; these dysfunctional branches can be removed or pruned back. Cut branches back to the node, which is a small swell where one tree branch attaches to the next.
Problems to Watch For
These general winter pruning tips should help with most pruning situations, however there are some special cases. If stems grow at a close angle, making a V to one another instead of a U, your tree may have included bark, which is a technical term for bark that grows between the two limbs. This can become a weak point for the tree. To prevent an old tree from breaking during a winter storm at this weak point, it's a good idea to secure the limb with a cabling system. A landscaping company with accreditations can install either wedge-grips/cable or arbor-plex systems so you can enjoy your tree without worrying about storm damage.
Co-dominant leaders, where two limbs of the same size branch out from the main trunk, also form weak points. In a healthy tree, one limb becomes dominant over time. When neither leader is dominant, the tree is vulnerable to breakage. Maples, oaks, and conifers are susceptible to co-dominant leaders.
Co-dominant stems are much more likely to break, especially in winter storms, than single leaders. If you spot a co-dominant leader early on, prune it away. If the limb is large, consider hiring a professional to trim your tree and reduce the risk of breakage.
Water sprouts develop after you prune and where you removed a limb. They zap the tree's energy. You may leave one water sprout and train it to replace the missing limb or prune them all away to preserve the tree's shape.
Tree Care After a Storm
After heavy snows or ice storms, trees and shrubs can sustain damage. That same foot of snow you were shoveling off your walkway is resting on the branches of your rhododendron, for instance. It's important to brush off snow from trees and shrubs before it freezes, since the weight can cause limbs to snap or deform. Gently lift branches upward with a broom and shake the snow off, starting near the top of the plant. If snow has already frozen on the branches, or if there’s ice, it’s best to wait until temperatures rise above freezing. Inspect your trees and shrubs after a storm, removing any wood that has fallen.
Prune back broken branches, making a cut where they join the main limb. If you need tree work on large trees or you're not quite sure where to start, call a professional tree service. A tree company will clean up the storm damage, prune the tree for good tree health, and make cosmetic adjustments. For instance, a tree company may remove other branches that appear likely to come down in the next storm.
Since trees are dormant in the winter, you will not be able to tell right away whether parts of the tree have died. Wait until the tree resumes growth in the spring, then remove any dead growth.