Every year in January/February, I get many questions from concerned gardeners about Crepe Myrtle pruning. They ask something like “I see all of these Crepe Myrtles around town that have been completely chopped off. Should I do that to mine?”
If you have ever had the instinct that chopping off the entire top of a tree is a bad idea, follow your instinct! With the exception of fruit trees, tree experts generally frown upon the practice of topping trees. Topping stresses the tree, stimulates unhealthy growth that can cause disease and insect problems, and leaves huge, ugly wounds that are difficult to heal.
I have some theories about how this practice- also known as “Crepe Murder”- came to be. I think it evolved because landscapers who typically mow grass all summer need something to do in the winter so they can continue earning a living. Other reasons may include the fact that Crepe Myrtles make flowers on new branches. Chopping off every branch on the tree will stimulate the tree to grow a tremendous number of new branches to replace the ones it lost. Every new branch will make a flower, making for a very loud show in the summer. The final reason I think people started topping Crepe Myrtles is to control their size. They are often planted as small ornamental understory trees, but some varieties reach 25 feet tall, and that does not fit into the landscape design plans for some gardeners. Taking off the top of the tree keeps it small.
Since there are three reasons for committing “Crepe Murder”, I can easily come up with three reasons not to. Landscapers who need something to do in the winter can still prune Crepe Myrtles in January and February, following good tree pruning practices. Crepe Myrtles that are topped have an ugly shape and contract powdery mildew. This all but ruins the beauty of the blooms in the summer. Crepe Myrtles that are properly pruned still have a good amount of blooms. There are many good dwarf Crepe Myrtles and other smaller ornamental trees to fill the role of small ornamental understory tree in landscape designs. These days, there is no good reason for topping Crepe Myrtles.
January/February the best time to prune most trees (except Oaks) in Central Texas, including Crepe Myrtles. Before you grab the saw and the pruners, take the time to ask yourself “Why am I pruning these trees?” Keep these goals in mind:
1. Remove dead and diseased wood. Make sure you can tell the difference between a dead branch and a live one during the winter. In certain trees, like Crepe Myrtles, it can be hard to tell the difference between dead wood and live. You can tell by using your fingernail to lightly scratch off the top layer of bark. If the tissue underneath is green, then the branch is still alive.
2. Remove branches that are hitting a roof, building or hanging in a walkway, driveway or street.
3. Remove crossing branches that rub together and create wounds that cannot heal. Also remove branches that are growing into the center of the tree and will start rubbing each other during this growing season.
Pruning for any other reason should be kept to a minimum. I recommend lightly pruning Crepe Myrtles again in the summer after their first flush of blooms for the same reasons listed above. After pruning it is a good idea to replenish the mulch around the base of your tree, or add a mulch circle if you don’t have one already.
Try to make your cuts at the collar of the branch- the spot where the branch grows out from the trunk. The collar contains specialized cells that will heal over wounds. Look at the Native Tree Growing Guide for a diagram of how to make a proper pruning cut.
by Colleen Dieter