Crepe myrtle (Lagerstroemia Indica) is a popular, easy to grow tree in the right setting. Blooms occur in summer, when most other trees have long since stopped blooming. These Southern favorites provide shade, and feature attractive, peeling bark and are easy to care for. Crepe myrtles bloom in colors that range from purple to deep red to bright pink, and the leaves of crape myrtles provide colorful foliage in autumn. Crepe myrtles reach mature heights of 15 to 25 feet, but container varieties reach a height 5 feet or less. They do best in sunny areas, and once established, are drought tolerant.
Sometimes spelled crape myrtle, these trees or shrubs have traditionally needed a warm climate. They flourish in U.S. Department of Agriculture plant hardiness zones 7a through 9a. But if you live in a colder climate, there are many hybrid crepe mytles that can survive in zone 6, and some can survive in zone 5 if they're planted in a protected area.
Crepe myrtle needs to be watered regularly for the first two months. Check the soil before watering, then let a hose trickle at the base of the tree whenever the soil is dry to a depth of 3 inches. Wait a day or two to water if the soil feels cool and moist. As a rule, water once or twice per week during dry weather, about 1 inch of water per week. Once the roots are established, the tree rarely requires supplemental water. However, crepe myrtle benefits from an occasional watering during hot, dry weather, especially while the tree is blooming. Water deeply and slowly to saturate the root system, then don't water again until the soil is dry. A 2- to 3-inch layer of mulch, either bark chips or compost, nourishes the soil and prevents moisture evaporation.
Crepe myrtle benefits from regular feeding of a balanced fertilizer with a ratio of 10-10-10 or 12-12-12. Too much fertilizer, however, can invite pests and disease and may create lush growth at the expense of blooms. Feed a newly planted crepe myrtle 1 teaspoon of fertilizer every month from spring until late summer. After the first year, feed the tree each spring. To determine the amount of fertilizer for an established tree, measure the ground under the widest part of the canopy, or top of the tree, then provide 1/2 pound of fertilizer for every 100 square feet. Sprinkle the fertilizer evenly on the ground, then water deeply.
Pests and Disease
Healthy crepe myrtle is relatively disease-resistant. However, overwatering, humid conditions, lack of sunlight, overcrowding and lack of adequate air circulation may cause powdery mildew, a fungus that leaves a powdery gray or white coating on the leaves. Leaf spot and other fungal disease are less common. Plant disease-resistant varieties, especially if you live in a warm, damp climate. Clip damaged growth and dispose of it properly to prevent spread of disease. Remove suckers and small sprouts that grow from the base of the plant, as this growth is susceptible to powdery mildew that travels to the main part of the tree. Crepe myrtle is sometimes bothered by aphids can be removed with a strong stream of water at affected areas. Avoid using insecticides, which kill lady beetles and other beneficial predatory insects that keep aphids in check.
Pruning depends on the desired size and shape of the tree. For example, if you want to grow crepe myrtle as a small shrub, cut the plant down to 6 inches above the ground every year without harming the tree. Otherwise, prune sparingly to maintain the tree's natural shape. It is best to buy a small variety if you want it as a shrub. When pruning, remove rubbing, crossing or damaged branches and twiggy, spindly growth. Shorten excessively long outer branches. To prevent loss of flower buds, prune crepe myrtle before new growth emerges in late winter or early spring. Before and after pruning, sterilize your pruning tools in a solution of 1 part household bleach to 3 parts water and let air dry. Well-established trees generally require little pruning if they have been carefully pruned the first few years.