Since we’re thawing out a bit, you might be looking for something to leave the house. There are a few tasks that you can focus on to prepare for spring, including pruning your trees. An old rule of thumb was to prune in winter while the plant was dormant. We need to be a little more specific for the best results, but it’s a start. When to prune depends on the species, but for most, late winter to early spring is the best time to prune.
Pruning towards the end of the dormancy period has several benefits, including: 1) Limited time remaining before the tree or shrub begins its spring growth and healing process. 2) Avoid certain diseases and pests. 3) Provides easier view and access with no foliage.
Oak wilt can be a devastating disease and it continues to spread across Minnesota. Therefore, oaks should not be pruned between April and mid-July. If an oak tree is damaged or wounded during this period, it is best to cover the wound surface with a water-based paint or cut sealer to minimize the attraction of pests that can spread the disease.
Fruit trees such as apples, crab apples, mountain ash, and hawthorn should be pruned from February to early April. This will reduce the likelihood of fire blight bacterial disease and infection. Pruning in autumn or early winter can lead to drying out and withering at the interfaces.
Trees with sap “bleed” in late winter or spring. While it may look alarming, it does no harm to the tree. One option with these types of trees or shrubs, such as maple, box, birch, and walnut or butternut, is to prune them after their leaves are fully developed in late spring or early summer. However, never remove more than a quarter of the living leaves.
Early spring flowering trees and shrubs such as forsythias, flowering plums, lilacs, azaleas, chokeberries, chokecherry, and flowering crabs should not be pruned in late winter or early spring. Instead, these early bloomers should be pruned after flowering is complete. If they are pruned at any other time, after the flower buds are planted, you will cut off the next spring’s flowers.
Remember that late winter and early spring are the best times to prune many of your trees and shrubs. Do your research, have the right tools, and be careful.
For more information on trimming, go to www.extension.umn.edu and search for trimming. You can also contact your local branch office. Residents of Stearns, Benton, and Morrison Counties can email [email protected] or call extension 320-255-6169. 1.
