Crape Myrtle, Crapemyrtle, Lilac Of The South, Summer Lilac, Crepe Myrtle
Because Lagerstroemia indica is available in a variety of growth patterns and potential growth height care is necessary in the selection of an appropriate variety for a specific location in the landscape. Tree form varieties of crape myrtle are best planted in full direct sunlight 15 to 20 feet away from the footprint of the roofline of a home. Upright varieties should be planted at 12 – 24 feet spacing. Shrub varieties of crape myrtle are available that may be planted closer in a bed located away from the roof line or in a bed that faces west or southwest to promote sunlight exposure. Smaller varieties can be successfully grown in large containers. Crape Myrtles tolerate a wide variety of soil conditions. The addition of organic matter and expanded shale is recommended for soils that contain a large proportion of clay. While crepe myrtle can be grown from seeds collected from the seedpods that ripen in the fall and can be planted in the spring, propagation is generally more successful by root cutting taken in the early spring and by softwood or hardwood cuttings. The wood cuttings should be taken in the spring. Each cutting should be 6-8 inches in length with 3-4 nodes per cutting. Rooting hormone is recommended.
Crape Myrtles are generally tolerant to occasional dryness once established. Deep watering performed periodically during the heat of summer is necessary during the first year following planting. Watering the base of the tree form varieties is best in order to reduce the risk of leaf diseases.
Unless a soil sample has demonstrated unique deficiencies in a site of Crape Myrtles, a moderate spring application of a balanced garden fertilizer (10-10-10) is recommended. Fertilizing during the hottest period of the summer is not advised. Slow-release versions of a balanced fertilizer are preferred.
All Crape Myrtles bloom on new wood. Pruning should be performed in winter or early spring. Larger forms of Crape Myrtles should be pruned by removing sucker growth coming from the ground, small twig growth, and crossing branches. Large varieties should be developed with an open pattern while removing side branches up to 5 feet above the ground. The removal of spent flowers will promote repeat blooming.
While Crape Myrtles, when exposed to full sun have few serious problems, powdery mildew, sooty mold, cerocospora, and aphids may occur. Powdery Mildew caused by the fungus Erysiphe lagerstroemiae is one of the most common problems of Crape Myrtles. Planting resistant varieties (Lagerstroemia indica x fauriei) is the best prevention followed by locating Crape Myrtles in full sunlight. Removing sprouts from the base of the plant assists in control. Cercospora Leaf Spot is caused by the fungus Cercospora lythracearum most commonly occurs during warm moist weather. Yellow spots appear on the leaves. Good air circulation and avoiding crowding of the plants is the best prevention. Crape Myrtle Aphids are small pale yellowish green in color with a black spot on the abdomen. The aphids overwinter as eggs. The aphids feed on young leaves which become yellow. Several predators feed on the crape myrtle aphid. Predators of aphids include ladybird beetles (ladybugs) and their larvae (immature forms), green lacewings and their larvae, hoverfly maggots, parasitic wasps, and entomophagous (insect feeding) fungi. Sooty Mold over the leaves and stems is unsightly, however, the condition does not harm the crape myrtle. In severe cases, the mold can be washed off with water. Prevention of sooty mold is dependent on control of Crape Myrtle aphids.