The crape myrtle, Lagerstroemia indica, is a popular deciduous shrub or small tree known for its vibrant and long-lasting summer flowers. Proper pruning ensures its long-term health, maintains its desirable natural shape, and maximizes its flowering potential each year. Unlike many ornamental plants, the crape myrtle blooms exclusively on new growth. Selective winter pruning directly influences the quantity and quality of the following season’s floral display. This careful maintenance is aimed at enhancing the tree’s natural vase-like form while removing growth that hinders air circulation or structural integrity.
Timing and Necessary Tools
The best time to prune a crape myrtle is during its dormant period, specifically in late winter or very early spring, typically from late January through mid-March. Pruning too early, such as in the fall or early winter, can stimulate new growth during a mild spell, which is then highly susceptible to damaging frost or freezing temperatures. Waiting until late winter ensures the plant is fully dormant and minimizes the risk of cold damage to tender new shoots.
Pruning must be completed before the emergence of new spring growth so the plant can direct its energy toward producing strong, healthy branches and flowers. To accomplish this task effectively, a few sharp tools are necessary for making clean cuts that heal quickly. Bypass hand pruners are suitable for small branches up to about a half-inch in diameter. Loppers are needed for cuts between one-half and one-and-a-half inches thick, and a pruning saw should be used for any larger limbs.
Step-by-Step Pruning Technique
The process begins at the base of the plant by removing suckers, which are small, rapid-growing shoots that sprout from the roots or the base of the trunk. These growths should be cut off completely at ground level or flush with the main trunk to prevent them from diverting energy from the desired main structure. Next, address the tree’s overall health by removing any wood that is dead, diseased, or damaged, often referred to as the “3 D’s.” Eliminating this unhealthy wood prevents the spread of potential pathogens and encourages better air circulation throughout the canopy.
Attention then shifts to shaping the canopy, starting with the removal of any branches that are growing inward toward the center of the tree. This inward growth, along with branches that cross or rub against each other, should be eliminated to prevent friction damage and to open up the center for sunlight and air penetration. The goal is to maintain the plant’s natural, open vase-like form, which showcases the smooth, multi-toned bark that develops on mature trunks. Thinning out small, twiggy growth from the interior of the canopy also helps achieve this open structure.
When making cuts to reduce the length of a branch, always prune back to a point just above a strong, outward-facing bud or to a lateral branch. This technique directs the subsequent growth outward, preserving the desired open shape. Larger branches should be pruned back to the branch collar, which is the slightly swollen area at the base of the branch where it connects to the main trunk or a larger limb. Cutting back to this collar promotes proper wound healing and minimizes stress on the plant.
The final step involves lightly pruning the tips of the previous year’s growth if necessary, specifically to remove old seed heads or spent flower stalks. This is achieved by tracing down to the point where the stem meets a branch or a strong lateral bud and cutting about six to twelve inches above that intersection. However, this reduction in height should be minimal and is not always required for established plants. Excessive removal of the upper canopy is detrimental to the plant’s health.
Preventing “Crape Murder”
The common and highly damaging practice of severely cutting back the main branches, often called “Crape Murder,” should be avoided entirely. This involves indiscriminately topping the main limbs, which ruins the plant’s natural form and creates unsightly, swollen knobs, or “knuckles,” at the cut sites. This practice is performed with the mistaken belief that it is required for abundant flowering or to control the plant’s height.
Instead of producing strong, graceful limbs, this severe topping encourages a flush of weak, spindly shoots, known as epicormic growth, from the cut ends. These new shoots are structurally unsound and often too weak to support the weight of the summer flowers, causing them to droop or break easily during rain or wind. Topping also forces the tree to expend significant energy on healing large wounds, which can weaken the plant and increase its susceptibility to disease and insect infestations. The appropriate solution for a crape myrtle that is too large for its space is to plant a smaller cultivar, rather than drastically reducing the height of a mature tree.