The best season to prune your trees depends largely on their species. In a pinch, a qualified professional can prune almost any tree at almost any time of the year. This is especially relevant in cases where the tree poses a safety hazard, and/or when removing dead wood from it. However, for routine maintenance, here are some general guidelines you can follow to get the most out of your tree pruning.
Deciduous Trees
The best time to prune most deciduous trees, such as maples, cottonwoods, and birches, is in late fall or winter, after the leaves have fallen off and the tree has gone dormant for the season. During these months, the tree will heal more quickly from the wounds that pruning inevitably leaves, and pests and pathogens will not be around to get into those wounds.
Evergreen Trees
Evergreens don’t go fully dormant the same way deciduous trees do. Still, their growth slows significantly in the winter months, and it’s best to prune them in the winter or very early spring, before this growth speeds back up.
Flowering Trees (early-blooming)
Trees that bloom in early spring are flowering from buds that grew the year before. For this reason, it’s best to wait until they’ve flowered to prune them. Otherwise, you’ll be removing some of those would-be flowers and the tree won’t look as nice. Common examples of these early-bloomers here in Michigan include magnolias, redbuds, and Bradford pears.
Flowering Trees (late-blooming)
Trees that bloom in early summer are flowering from buds that grew earlier in the same year. They should be pruned in early spring, before they start blooming. Common examples of these late-bloomers in this area are basswoods, catalpas, and dogwoods.
Fruit Trees
If your tree produces fruit (the kind that you actually eat) it’s best to prune them in late winter. This will give you the best fruit production during the summer/fall. Here in Michigan, “fruit tree” almost always refers to apple trees (and occasionally pear trees.) Notably, it does NOT refer to trees that have a fruit in their name, but don’t produce fruit that most people would want to eat, such as black cherrys, crabapples, and mulberrys.
Special Exceptions
A small number of trees are prone to certain diseases during certain seasons of the year, and MUST be pruned during a safer season. These include most oaks (oak wilt) and American elms (Dutch elm disease.) Prune these during the winter (November 15th - March 31st.) Pruning outside of this time frame risks spreading these diseases and infecting nearby trees, resulting in dead trees, angry neighbors, and even lawsuits to the tune of many thousands of dollars.
