Crepe myrtles are highly favored landscape trees in warmer climates, prized for their extended summer blooming period and attractive peeling bark. They produce vibrant flowers exclusively on new growth each season, making pruning an important maintenance task. Understanding the plant’s growth cycle and when to make major cuts is essential for maintaining its natural, graceful form and ensuring optimal flowering.
The Ideal Time for Major Pruning
The most appropriate window for performing major, structural pruning on a crepe myrtle is during its dormant period, generally between late winter and very early spring (January through March). This timing ensures the tree is without leaves and has not yet begun to push out new growth. Pruning during this stage is beneficial because crepe myrtles bloom exclusively on new wood, meaning flowers are produced on the growth that develops in the current season.
Making significant cuts during dormancy minimizes stress, as the plant’s energy reserves are stored in the roots. Pruning too early in the winter can stimulate new, tender growth that is vulnerable to damaging frosts. Waiting until the threat of the coldest weather has passed, but before the buds swell, allows the tree to immediately channel energy into robust, flower-producing shoots. This timing maximizes the plant’s ability to recover quickly and produce a strong display of blooms later in the summer.
Structural Goals for Pruning
The primary goal of dormant pruning is to enhance the tree’s health and natural, often vase-like, structure. This involves the selective removal of specific types of growth, commonly referred to as the three D’s: dead, damaged, or diseased wood. Removing these compromised branches cleans up the tree and prevents potential entry points for pests and pathogens.
Another structural focus is eliminating suckers, which are fast-growing shoots emerging from the base of the trunk or roots. Suckers compete with the main canopy for nutrients and water, so they should be pruned as close to the ground or trunk as possible. Gardeners should also remove small, twiggy branches growing inward or crossing and rubbing against other limbs. Thinning this weaker interior growth improves air circulation and allows sunlight to penetrate the canopy, promoting overall plant vigor and bloom quality.
Avoiding Improper Pruning Techniques
The most harmful and widespread mistake in crepe myrtle care is “Crepe Murder,” which involves severely cutting back large, established branches to blunt stubs. This topping technique ruins the tree’s natural form, causing unsightly, knobby growths at the cut sites. These severe cuts force the tree to produce a dense flush of weak, spindly shoots that are less able to support the weight of summer flowers and are more susceptible to breaking.
Proper pruning relies on making thinning cuts, which involve removing entire branches back to a main trunk or a larger lateral branch. When cutting a larger limb, cut just outside the branch collar—the swollen area where the branch meets the main stem—which contains specialized tissues that help the tree seal the wound. For branches too large for hand pruners, use a saw, often employing a three-cut method to prevent the bark from tearing down the trunk.
The objective should be to thin and shape the tree, preserving its natural, upright growth habit, rather than drastically reducing its height. Excessive pruning stresses the plant, forcing it to expend energy on regrowth and potentially delaying summer blooms. Focusing on selective thinning maintains a strong, healthy structure without resorting to destructive cuts.
Light Trimming During the Bloom Season
Outside of major structural pruning in late winter, the only other trimming should be light maintenance during the summer bloom season. This activity, known as deadheading, involves removing spent flower clusters after their color has faded. Deadheading encourages the crepe myrtle to redirect energy from seed production into new lateral growth, potentially leading to a second, smaller flush of blooms later in the season.
Deadheading should be performed right after the first round of flowers finishes, typically in mid-summer. It is important to cease all deadheading by late summer, generally around early August. Trimming too late stimulates new growth that may not harden off before the first frost, potentially damaging tender shoots. This in-season activity is purely for extending the display of flowers and should not involve structural cuts to the main branches.