Pruning Crape Myrtles
Crape myrtles are a very common landscape tree in Lee County. And there is good reason too. The tree has a wonderfully long bloom time and beautiful bark – a plus for the winter garden. Around this time of the year, you see one of the worst horticultural practices being committed on these trees. Those of us in the horticultural world refer to it as crape murder.
Many people incorrectly believe that crape myrtles must be severely pruned back to an arbitrary height to flower well. This practice is also known as topping. Topping is extremely harmful to the tree – it can increase the amount of stem decay, which can cause the whole tree to die. Topping also results in more dead branches in the canopy.
When a tree is topped, many vigorous, succulent shoots start to grow from the cut areas. These shoots are poorly attached and can actually break off with high winds. The succulent shoots also attract aphids, which love to feed on new plant growth. An increase in the aphid population can result in more sooty mold. Sooty mold is a blackish fungus that can appear on the leaves in summer when aphids are present.
Topping destroys the natural beauty and form of the tree. This is especially apparent in the winter after the leaves have dropped. Topped crape myrtles are graceless, mutilated trunks.
And what about the bloom? Topping can decrease the length of bloom time and the number of flower clusters since only one flower cluster blooms per shoot.
So what is the correct way to prune crape myrtles? Actually crape myrtles require very little pruning. Shaping and pruning starts with picking the right cultivar for the location you have in mind. Not all crape myrtles were created equal – they range greatly in mature height. By picking a crape myrtle that fits into your landscape, you cut down on the amount of maintenance work you will need to do.
If you must prune, wait until late winter or early spring. Make cuts back to a main branch or trunk – do not leave stubs. You will want to locate the collar region of the branch, this is a region that will heal quickly and seal off the wound – it is not flush with the trunk! Do not apply pruning paint.
When choosing which limbs to remove, follow the three Ds of pruning. Remove branches that are dead, diseased, or damaged.
If you want to form a tree shape, you can limb up the tree. Remove limbs 1/3 to ½ of the way up the tree. This is a great way to show off the peeling cinnamon bark! Be careful not to remove limbs that are larger than 8” in diameter as these large branches can result in trunk decay.
Don’t let your crape myrtle be a victim! Proper planning and preventative pruning will help your crape myrtle develop into a gorgeous tree that will dazzle the neighbors. For more information on pruning crape myrtles, contact the Lee County Center of North Carolina Cooperative Extension at 919-775-5624.
Want more pertinent horticulture information delivered directly to your home computer? Subscribe to the Lee County home horticulture e-mail list. Simply send an e-mail to email@example.com with subscribe leehomehort in the body of the message. You will then be a member of firstname.lastname@example.org.