What kind of pruning is safe to do in the winter?
Ralph Edwards, Vista, NY
Lee Reich, a garden consultant and author of The Pruning Book, replies: Woody trees, shrubs, and vines are often pruned during the winter. Generally, the best time for this type of pruning is after the coldest part of winter has passed. Wounds are then left exposed for less time, and, especially in cold climates, there is less chance for cold damage near cuts.
There are exceptions to this general rule of thumb. Plants such as peaches and nectarines, whose open wounds are readily infected by disease, are best pruned while they’re in bloom, when their wounds heal rapidly. And always prune spring-flowering shrubs, such as forsythia and winter jasmine, right after their blossoms fade. This way you don’t cut off any of the upcoming show.
On the other hand, feel free to prune shrubs that are valued only for their vigorous new growth, such as butterfly bush and St. John’s Wort, at any time during winter. Their old stems are often harmed by winterkill and break or fall off anyway. Depending on how cold your winters are, crape myrtle stems may or may not be affected by winterkill. In colder areas, you can grow crape myrtle as a mound of young flowering stems and cut them to the ground anytime in winter. In mild-er areas, though, you can grow crape myrtle as a large shrub, pruning it back to the more permanent stems in late winter.
Finally, you can prune very hardy shrubs, such as gooseberry and currant, anytime during winter. Their pruned stems rarely, if ever, are damaged by winter cold.