The weeping cherry tree (Prunus subhirtella ‘Pendula’) is known for its spectacular spring floral display. Understanding when to prune a weeping cherry tree is a vital component in maintaining the health and beauty of these specimen trees.
Fall is considered the optimal time to prune weeping cherry trees. Dormant trees withstand the stress of pruning better. In addition, without leaves it is easier to determine the structure of the tree. Crossed or damaged branches are removed at this time, as well as branches that are upright. Branches that are weeping too low to the ground are often tipped to a better height. Pruning in the fall may reduce some of the spring bloom, but will be better for the overall health of the tree.
Weeping cherry trees are susceptible to many fungal and bacterial diseases, especially if they have been drought stressed. Diseased branches are pruned immediately throughout the growing season and discarded so they do not re-infect the healthy tree. Shears used to remove diseased material are disinfected between cuts with a 10% bleach and water solution.
Pruning in winter is not recommended. Many fungal spores are active during the winter months and are spread by airborne contact. Any infected material that has fallen to the ground can potentially contaminate pruning cuts made in the winter.
Cherry Bark Tortrix is an insect pest common in Europe that also invaded the Pacific Coast of North America in the early 1990s. The insect bores into open wounds, such as those of recently pruned trees. For those living in the Pacific Northwest, there is only a narrow window around October when the insects are not active and it is safe to prune weeping cherry trees.