By Sally McNamara, Master Gardener
Don’t let the fact that there is still snow on the ground deter you from getting outside and pruning the trees and shrubs in your yard that need it. Late winter and early spring is the best time to prune most trees and shrubs. This article will provide some advice on how to go about it to make your plants and yourself pleased with the result.
Believe it or not, the biggest mistake with pruning shrubs is being too conservative. While it is certainly possible to REMOVE too much, most pruners LEAVE too much. The other major mistake is not using sharp, effective pruning tools. Cutting is easier and better for the plant with the right size sharp tool. Disinfecting tools with a disinfecting wipe between plants is ALWAYS a good idea to prevent any potential for disease spread.
There are 5 reasons to prune:
- Remove diseased, damaged or dangerous material
- Develop a strong framework for growth
- Improve air circulation and fruit production
- Improve a plant’s shape
- Control size – although planting the right-sized plant initial is a better solution
Most pruning of both trees and shrubs is best done in late winter/early spring when the plants are just coming out of dormancy, the form of the plant without the leaves is visible, and the sap is beginning to flow. Sap moving into the pruning wounds helps the healing process and prevents drying out of the plant material. Winter winds will extract moisture from the plant through the pruning cuts so fall is NOT a good time to prune. The one big exception to this rule is maples and birch which can be pruned after the spring sap flow has slowed.
Spring flowering plants should typically be pruned AFTER they flower. Summer and fall bloomers are best pruned in the late winter/early spring.
Pruning during the growing season opens the plant to disease and insect damage. Oaks especially should not be pruned between April and August to avoid the picnic beetle which spreads oak wilt.
Plant material damaged by storms, etc. should be removed as soon as possible if it could cause harm to people or structures. Diseased or insect damaged material should be removed to limit spread of the problem. Discarding of diseased material should be done with care – bag and discard in the trash for small amounts. Transfer to a facility that composts material to a proper temperature for larger quantities.
The magic words in pruning are “branch collar” followed by “branch bud”. Using the three-cut method to remove most of the branch weight before complete removal is important on large branches to prevent ripping the bark down the tree.
Branches should always be cut back to the branch collar and cut cleanly at that point. Cutting further in or leaving a stump out decreases the tree’s ability to grow protective bark over the wound and increases the chance of disease and insect damage.
Smaller branches should be cut at a bud point to encourage growth and not leave material for decay. When pruning away dead material, prune well back to living material.
General pruning of shrubs should be done to improve overall plant health.
RECOMMENDED: Removing old growth to the trunk or soil results in a refreshed plant.
DISCOURAGED: Shearing the plant encourages more growth in the top part, limiting light and air to the interior, causing dead inner branches.
An excellent reference book on pruning is ESSENTIAL PRUNING TECHNIQUES: Trees, Shrubs, Conifers by George E. Brown and Tony Kirkham.
So, put on your warm jacket and boots and give your trees and shrubs a proper haircut before the warm days of spring!
Video: Pruning Tips
Video: Pruning Basics for Gardeners