The Crepe Myrtle (Lagerstroemia indica) is a highly favored ornamental tree known for its extended summer bloom period and attractive exfoliating bark. Proper pruning is a necessary practice to maintain the tree’s health, establish structural integrity, and maximize the production of vibrant flower clusters. A thoughtful approach ensures the tree maintains its graceful, natural form while encouraging the strong new growth that produces the season’s blossoms. This guide details the correct techniques for successful pruning.
Optimal Timing and Required Tools
The ideal window for significant pruning is during the tree’s dormant season, typically spanning from late winter into early spring, specifically around February or March. Pruning during this time ensures the tree is leafless, which allows for a clear view of the branch structure, and it occurs just before the new growth cycle begins. Waiting until after the most severe cold weather has passed reduces the risk of new growth being damaged by an unexpected freeze.
A successful pruning job requires three types of cutting tools appropriate for the size of the wood being removed.
- Small branches (less than half an inch in diameter) are best handled with sharp bypass hand pruners.
- For medium-sized branches (half an inch up to about 1.5 inches thick), long-handled loppers provide the necessary leverage for a clean cut.
- Branches exceeding 1.5 inches in diameter require a pruning saw or pole saw to ensure precision and prevent damage to the branch collar.
Before beginning any cuts, sanitize your tools by wiping the blades with a solution of diluted bleach or rubbing alcohol. This simple step prevents the potential spread of diseases or pathogens between cuts or from one plant to another. Using sharp, clean tools also ensures that all cuts are smooth and precise, which allows the tree to seal the wound more efficiently.
Essential Structural Pruning Techniques
The primary goal of structural pruning is to shape the tree into a sturdy, natural, and often vase-like form while encouraging good air circulation throughout the canopy. This involves three main categories of cuts focused on improving the tree’s overall architecture and health.
Begin by systematically removing any wood that is visibly dead, diseased, or damaged. This material can harbor pests and pathogens that threaten the living parts of the tree, so its removal is the first step in maintaining tree health.
Next, focus on eliminating branches that are crossing or rubbing against one another. When two branches persistently rub, they wear away the protective bark, creating open wounds that can serve as entry points for insects or fungal infections. Removing these conflicting branches also helps to open up the interior canopy, allowing for better light penetration and airflow, both of which are beneficial for growth and bloom production.
Another technique is raising the canopy, which involves removing the lowest limbs along the main trunks to expose the attractive, often mottled bark beneath. This is usually done by gradually removing branches up to a height of five feet or more, which prevents low-hanging branches from touching the ground or interfering with surrounding areas. For all structural cuts, it is important to cut back to the branch collar, which is the slightly swollen area where a branch meets a larger trunk or another branch. Cutting just outside this collar allows the tree’s natural healing process to effectively compartmentalize the wound.
Avoiding Heavy Reduction Cuts
A common but improper practice to avoid is making heavy reduction cuts, an action often described as “Crepe Murder” by arborists and horticulturalists. This technique involves cutting large, established scaffold branches back severely to thick stubs or “knobs,” often in an attempt to control the tree’s height or size. While the tree is remarkably resilient and will likely survive this treatment, it is highly detrimental to its long-term health and aesthetic appeal.
The consequence of topping the tree is the aggressive production of numerous weak, vertical shoots, often called water sprouts, which grow rapidly from the cut ends. These shoots are structurally unsound because they lack the strong branch collar attachment of naturally formed branches. When these weak, whiplike growths bear the weight of the summer’s blooms, especially after heavy rain, they are prone to bending or breaking off.
Severe reduction cuts also disrupt the tree’s natural energy reserves and can lead to delayed or significantly reduced flowering in the subsequent season. Furthermore, the large, open wounds created by cutting into thick wood do not heal as effectively as smaller, proper cuts made at the branch collar. These large, flat cuts can create entry points for moisture, leading to decay, rot, and a weakened structural integrity over time, resulting in a disfigured, unnatural appearance.
Ongoing Maintenance and Basal Growth
Outside of the major dormant season pruning, minor maintenance can be performed throughout the year to keep the tree tidy and encourage maximum bloom potential.
Removing Suckers
One recurring task is the removal of suckers, which are vigorous shoots that emerge directly from the base of the tree or from the roots in the surrounding soil. These suckers should be removed as soon as they are observed, cutting them off cleanly at the point of origin. This prevents them from diverting essential energy and nutrients away from the main tree structure.
Deadheading
Deadheading is the optional removal of spent flower clusters and seed heads during the summer blooming period. This cosmetic practice is not mandatory for the tree’s health, but removing the brown, fading blooms encourages the tree to redirect its energy toward producing a secondary flush of flowers. Deadheading is typically performed in mid-summer, such as in July, to ensure enough warm weather remains for the subsequent blooms to fully develop before the season ends.