The crepe myrtle (Lagerstroemia species) is a popular ornamental tree known for its extended summer bloom and attractive exfoliating bark. Proper pruning is necessary to ensure vigorous, healthy flowering and to maintain a pleasing structural form. Understanding the correct sequence and timing for cuts is essential for achieving a beautiful, balanced plant structure.
When to Prune and What Supplies You Need
The optimal time for pruning crepe myrtles is during the late winter or very early spring, typically between January and March, while the plant remains dormant. Pruning during this window ensures that the plant’s energy reserves are available for new growth and flower production once spring begins. Cutting the plant earlier can stimulate tender new growth highly susceptible to cold damage from late frosts. Pruning after new leaves emerge in the spring will remove developing flower buds, significantly reducing the summer display.
Preparing the right set of tools is important for the work. For smaller, one-year-old twigs and shoots, use a sharp, clean pair of bypass hand pruners. Branches up to approximately 1.5 inches in diameter require long-handled loppers to ensure a clean cut. Larger, older limbs that exceed the lopper’s capacity should be removed using a specialized folding pruning saw.
The Essential Cleanup Cuts
The first step involves removing all growth that originates from the base of the plant or directly from the roots, known as suckers. These vigorous shoots divert energy away from the main structural trunks, hindering flower production. These growths should be cleanly severed right at their point of origin, often requiring a sharp knife to cut below the soil line.
Next, remove any wood that is dead, diseased, or visibly damaged from storms or pests. Dead wood can harbor insects and diseases, and damaged limbs represent a structural weakness. These cuts should be made back to healthy wood, which is indicated by a slight color change in the cambium layer just beneath the bark.
The final cleanup step focuses on branches that are rubbing against each other or crossing through the center of the canopy. Rubbing creates open wounds on the bark, providing an entry point for pathogens and weakening both limbs. All of these unwanted branches should be removed entirely, cutting back precisely to the branch collar without leaving a stub. The branch collar is the slightly swollen area where the branch meets the trunk and contains cells necessary for proper wound closure.
Strategic Shaping and Managing Height
After completing the cleanup cuts, the focus shifts to establishing the desired vase-like structure that showcases the crepe myrtle’s multi-trunk habit. This involves selectively removing smaller, interior branches that are growing inward and crowding the canopy. Thinning the center improves air circulation, which reduces the likelihood of common fungal issues like powdery mildew.
Managing the overall height and spread is accomplished through selective reduction cuts, rather than indiscriminate topping. To reduce the plant’s size, cuts must be made just above an outward-facing bud or above a strong, lateral side branch, known as drop-crotching. This method ensures the remaining branch will continue to grow in a desirable direction while maintaining the plant’s natural form.
These shaping cuts should prioritize selective, minimal removal to achieve the desired effect. The goal is to enhance the existing structure, not to drastically alter it in a single pruning session. Removing no more than one-third of the total canopy volume in any given year is a guideline to prevent undue stress on the plant.
Why You Must Avoid Crape Murder
The most common and damaging mistake made when pruning crepe myrtles is the practice termed “Crape Murder.” This refers to the severe, indiscriminate cutting back of large, mature trunks to an arbitrary height, leaving behind thick, blunt stubs. This technique is often mistakenly applied to control the height of a variety that has outgrown its space.
This severe heading wound forces the tree to rapidly produce a dense cluster of thin, whip-like shoots, often called a “witches’ broom.” These rapidly grown shoots are weakly attached, structurally unsound, and prone to breaking off during heavy weather. Topping also delays flower production and permanently ruins the graceful, natural architecture of the trunk and canopy. Proper pruning focuses on selective cuts to maintain shape and health, never on chopping the main structure.