Pruning crapemyrtles (Lagerstroemia) can confound gardeners because there are plenty of bad examples lining the streets of the South (and beyond, with the introduction of hardier crape myrtle varieties). Here are the best strategies for pruning crapemyrtles to encourage better bloom, form and health.
First, remember that pruning is not a requirement. By choosing a variety with a mature size that matches the allotted space in your garden, you may never need to prune your crapemyrtle. The most you might do would be to remove the old seed heads at winter’s end; however even this is optional, as they will drop away on their own.
But if the crapemyrtle outgrows its space, or if you wish to encourage a neater, more treelike shape, pruning can be done. The best time for pruning crapemyrtles is in late winter or early spring, before the plant begins to grow and leaf out. (Although damaged or diseased branches should be removed at any time of year.)
To reduce the overall size of a crapemyrtle that has outgrown its space:
- Remove low limbs to create space near the ground plane and leave the plant's bulk in its canopy. Cut the limb just above the swollen point where it meets the trunk, which is known as the branch collar.
- An entire trunk can be removed if a multitrunked crapemyrtle is too close to a building, driveway or other structure.
To maintain a crapemyrtle at a certain maximum height:
- Remove twiggy growth from the top and sides of the plant, leaving lower side branches in place.
- If a much shorter shrub is desired, cut the entire plant back to six inches tall. It will regrow.
To create a more open, tree-like structure for better appearance, air flow and access to sun:
- Remove branches from the center of the crape myrtle, particularly twigs and branches that cross another branch or a trunk, and shoots rising straight up through the canopy.
- Remove any suckers popping up from the base of the plant, leaving only several main trunks. These can be pulled while they’re still new, or clipped if more mature.
- As the crapemyrtle grows taller, prune away low branches so that the bottom of the canopy sits one-third or halfway up the trunks.
Pruning crapemyrtles should not involve “topping” them—in other words, cutting off all growth at a certain height. This only results in a messy, twiggy confusion of new growth.
