Just say no to ‘crape murder’

Published 12:00 am Wednesday, December 19, 2012

A poor horticulture practice in Louisiana and across the South involves one of our most beloved landscape trees. Each year, crape myrtles are pruned improperly, resulting in what those in the horticulture business refer to as “crape murder.” Typically crape murder occurs in December, January and February. However, this year butchered trees began appearing in September and are continuing at an ever-increasing pace. This is alarming and very concerning.  

Topping crape myrtle trees will result in a crew-cut appearance. The lush growth that occurs at these cut sites appears vigorous but is actually structurally weak and is more susceptible to fungus diseases such as powdery mildew. Worse yet, when people prune improperly over several seasons, unsightly, large, swollen knobs form at the point where pruning is done each year.

Crape myrtles need only occasional pruning, in most cases, to obtain the desired landscape effect. But many times these plants are butchered for no good reason. We often encounter gardeners who think they are supposed to prune their crape myrtles severely. Nothing could be further from the truth. For the overwhelming majority of us, enhancing the natural shape of our crape myrtles is most appropriate. Some gardeners have been told that crape myrtles need to be pruned severely to bloom well. This is not true. The flower clusters may be larger on topped trees. But the added weight on the ends of long branches causes them to bend over awkwardly, especially after rain. And since the tree is smaller, it actually produces fewer flower clusters.

To prune a crape myrtle properly, first decide if it needs to be pruned. As with any pruning project, you must have a specific purpose in mind before you begin. If you can’t come up with a good reason to prune your tree, leave it alone. If you do see something that calls for pruning, study the tree carefully and determine what needs to be pruned to accomplish the specific purpose you’ve identified. Examples of appropriate reasons for pruning include eliminating crossed and rubbing branches, removing low-growing branches, removing weak, thin branches from the inner part of the tree, trimming off old seed pods, creating a shapelier tree and keeping suckers removed from the base of the trunk. Avoid cutting back or shortening branches larger around

than your finger, although cutting larger branches back to a side branch or to the trunk when needed is fine.

With its smooth, muscular trunks, peeling bark, filigree of leafless branches in the winter and exceptionally long blooming season in summer, the crape myrtle is rightfully popular here. Make sure you keep yours looking its best.

Learn more about landscape horticulture work being done by LSU AgCenter specialists by viewing the “LSU AgCenter Hammond Research Station” Facebook page, or for more information contact the St. John Parish LSU AgCenter Extension Office at 985-497-3261 or visit www.lsuagcenter.com.

Mariah Bock is the LSU AgCenter County Agent for St. John Parish, she can be reached by email at mbock@agcenter.lsu.edu.