Successfully Pruning Crape Myrtles

Lee Ann Fields  |  5/23/2018 4:41:57 PM

During the past month or so, regarding pruning various landscape plants, the majority of the callers have either inquired into the proper timing for pruning shade trees or crape myrtles. Today I want to discuss the latter because of a disturbing trend in the landscape industry, especially throughout the South, known as “crape murder.” And, unfortunately, it is occurring earlier and earlier each year. “Crape murder” is referred to the practice of topping crape myrtles which gives them a crew-cut appearance. The pruning practice won’t actually kill crape myrtles, but why would anyone want to destroy one of the most popular landscape plants we have here in the South?

There are several misconceptions when it comes to pruning crape myrtles. These misconceptions include: crape myrtles bloom better when cut back, crape myrtles can be cut back to change their shape, young crape myrtles should be cut back to make them look fuller, and crape myrtles should be cut back to control their size. For example, a 20-25’ crape myrtle variety is genetically wired to use surrounding resources to fulfill that growth potential. Regarding overall plant shape, some crape myrtle varieties grow tall and upright, while others are shorter and spreading. Again, these shapes are controlled by genetics. It is best to select a plant variety that meets the size, shape and color requirements you are looking for in the beginning, than to fight the natural growth habits with annual pruning.

The lush vegetative growth that occurs following the harsh cuts appears vigorous, but it is actually structurally weak and is more susceptible to fungal diseases such as powdery mildew. Over time, crape myrtle shrubs and trees that have been severely cut back will develop unsightly, large, swollen knobs at the point where pruning is done each year. Additionally, fewer flower clusters are produced on crape myrtles that have been severely cut back. And, the flower clusters that are produced are adding weight to the structurally weak new growth, which causes the branches to bend over awkwardly, especially after it rains.

That being said, I am not indicating that crape myrtles should never be pruned. However, selective pruning of crape myrtles is much more desirable than excessive pruning techniques. The following lists several examples of appropriate reasons for pruning crape myrtles: eliminating crossed or rubbing branches, removing low growing branches, removing weak or thin branches, and keeping suckers removed from the base of the trunk. As a rule of thumb, try to avoid cutting back branches larger around than your finger, if at all possible. Regarding the question of the best time of year to prune crape myrtles is late January through early March.

As a side note, homeowners can eliminate the need to prune crape myrtles by selecting the choosing the right variety to meet their landscape needs. For example, place larger growing crape myrtle varieties away from structures and power lines. Instead, pick smaller crape myrtle varieties or dwarf varieties for placement in landscape beds near structures.

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