Crepe myrtles (Lagerstroemia indica) are deciduous shrubs or small trees known for their exceptional beauty and long-lasting summer blooms. Native to Asia, they are now a signature feature in landscapes across the United States, particularly in warmer climates. Their popularity stems from vibrant, crinkled flowers that appear from late spring through summer. The mottled, peeling bark and attractive fall foliage also contribute to their year-round appeal, making them a resilient ornamental plant.
Selecting the Site and Planting
The successful establishment of a crepe myrtle requires choosing an optimal location that satisfies its light and space requirements. Full sun exposure is mandatory for prolific flowering, meaning the plant needs a minimum of six hours of direct sunlight each day. Planting in a shady spot will result in fewer blooms and can increase susceptibility to common fungal diseases.
Consider the mature size of the specific cultivar; standard varieties can reach heights of 15 to 25 feet with a spread of up to 15 feet. Selecting an appropriate size prevents the need for drastic pruning later on. The soil should be well-drained, as crepe myrtles tolerate a range of soil types but will suffer from root rot in waterlogged conditions.
When planting, the hole should be dug two to three times wider than the root ball but no deeper. This encourages the roots to spread outward. Ensure the top of the root ball is set level with or slightly above the surrounding soil line to prevent moisture issues. After positioning the plant, gently loosen any circling roots and backfill the hole with the excavated soil, tamping lightly before watering thoroughly.
Watering and Fertilizing Needs
The watering schedule changes significantly as the plant matures. Newly planted trees require consistent moisture to establish a strong root system, generally needing deep watering once or twice a week during the first year, especially in dry periods. Soak the root zone completely, but allow the top few inches of soil to dry out between applications to prevent overwatering and root issues.
Once established (typically after the first year), crepe myrtles become drought-tolerant and require less frequent watering. Supplemental water is only necessary during extended drought conditions, about once every 10 to 14 days during dry spells. Deep watering during the six-week period before and during the bloom cycle can help maximize flower production.
Fertilization should be approached with caution, as excessive application, particularly of high-nitrogen formulas, will promote leafy growth at the expense of flowers. Use a slow-release fertilizer with a low nitrogen-to-phosphorus-potassium ratio, such as a 3-1-1 blend, in early spring as new growth emerges. A second, lighter application may be made in early summer. Avoid fertilizing after mid-summer or early August to allow the new growth to harden off properly before the cold weather arrives, which improves winter hardiness.
Pruning for Health and Shape
Pruning is often the most misunderstood practice in crepe myrtle care, with improper technique leading to “Crepe Murder.” The objective is to maintain the plant’s natural vase shape, encourage strong branches, and reveal the attractive, mottled bark. Proper pruning should be done during the dormant season, ideally in late winter or early spring before new growth begins.
Start by removing all suckers—vigorous, unwanted shoots growing from the base or roots—by cutting them as close to the ground as possible. Next, remove any dead, diseased, or inward-growing branches, as well as any crossing or rubbing branches. As the tree matures, gradually remove lower side branches from the main trunks up to about the five-foot mark to expose the ornamental bark.
Size control should be accomplished using thinning cuts, which involve removing an entire branch back to the trunk or a main lateral branch, or by selectively shortening branches by cutting back to an outward-facing bud. Severe topping, or “Crepe Murder,” involves cutting main branches back to thick stubs, resulting in weak, spindly new growth that cannot support the flowers and ruins the tree’s natural form. Selecting a dwarf or semi-dwarf cultivar that fits the space is the best way to manage size without resorting to harmful topping.
Managing Pests and Diseases
Crepe myrtles are generally resilient, but they are susceptible to a few common pests and diseases that require targeted management. One of the most frequent problems is powdery mildew, a fungal disease that appears as a white, powdery coating on leaves and buds, especially in humid conditions or shaded locations. Planting mildew-resistant cultivars and ensuring full sun exposure with good air circulation are the best preventative measures.
The crepe myrtle aphid feeds on leaf sap and excretes honeydew. This honeydew becomes the substrate for sooty mold—a black, unsightly fungus that interferes with photosynthesis in severe cases. Aphid populations can often be managed with a strong spray of water, or by applying insecticidal soap or horticultural oil if the infestation is severe.
Another prevalent pest is the Crepe Myrtle Bark Scale, which appears as small, white to gray felt-like insects on the bark and stems. Systemic insecticides, such as a dinotefuran soil drench applied in the spring, are the most effective control. A common physiological issue is a failure to bloom, which is usually traced back to insufficient sunlight or excessive fertilization.