The crape myrtle (Lagerstroemia) is a native of Southeast Asia, but it has become one of the most popular flowering shrubs/trees in North Texas. It is also one of the most useful. The crape myrtle provides abundant summer color with a minimum of maintenance and can flower for as many as 120 days. Crape myrtles are used in home landscaping and as street trees in community development. They are ideally suited for parkways and roadway settings since they are long-lived, withstand droughts once established and are relatively free of disease and insect problems. The flowers range in color from red, pink and purple with an attractive exfoliating bark and can be effectively mixed with other flowering shrubs.

Considerable breeding in the past few years has resulted in a number of new crape myrtle cultivars. Height ranges from 3 feet to 20 feet, making them versatile plants that lend themselves to specimen trees and cluster planting. Many of the newer varieties have improved flower color, better fall leaf color, beautiful bark and better cold and disease resistance than the older seedling types.

The popularity and widespread use of these beautiful plants has resulted in it being classified as naturalized for our area. In 1997, the crape myrtle was designated as the State Shrub of Texas.

The crape myrtle is commonly described as a multi-trunk medium to large shrub or tree.

Bark can be smooth or peeling, fluted, pale to light brown color. Fall leaf color may have a range of yellow, orange and red. The most desirable feature of the crape myrtle is the long stem with ruffled flowers in diverse shades of white, pink, red and purple flowers. The petals generally have six broad, fringed blades with the lower portion tapering into long slender shafts. The dry fruit contains seeds that are winged at the top.

The giant crape myrtle (L. speciosa) generally grows to 25 to 30 feet and some of the eighty varieties are valuable for commercial timber. This plant is native to India and has proven to be less hardy, restricting cultivation to warmer climes such as southern Florida, California and Hawaii.

Crape myrtle will grow under adverse soil conditions; however it thrives and flowers more profusely in well-prepared soil. The added work spent in preparation pays off with a much healthier plant. This includes digging a hole approximately twice as large as the root ball. The crown should be no deeper than it originally grew in the container or field. Then backfill with the same soil removed from the hole, breaking up clods and removing rocks or debris. Do not add amendments, as they do not encourage outward growth of the roots into the native soil. Amendments are most beneficial when incorporated evenly throughout the surrounding soil.

Water thoroughly to settle the soil around the roots and mulch to conserve moisture, reduce weeds and protect against extreme cold and heat. Three to five inches of shredded hardwood mulch or shredded leaves arranged over the planting hole is ideal. Mulching a larger area is even better.

Location is important to avoid stressing the plants during hot, dry summers.

For the first two months, water crape myrtles at planting and once a week in the absence of rain. A deep watering once a week is more beneficial than a light sprinkling more often.

Established plants will tolerate drought. However flowering will be enhanced if plants are watered if dry periods occur during the flowering season.

Place crape myrtles in full sun to encourage strong growth and generous flowering. Intense shade will reduce growth and increase disease problems such as sooty mold on the leaves and powdery mildew on flower buds and new growth. Large shade trees can also compete with crape myrtles for moisture causing poor growth and fewer flowers. Lack of sunlight and water are the most common causes of reduced growth and flowering.

Prune plants anytime during late winter or early spring before new growth appears. Avoid pruning in early fall before the first frost as this will result in new growth and prevents the plant from going dormant. Plants can be killed by severe freezes if not fully dormant.

Pruning encourages new shoots that form flowers. It also reduces the vegetative growth and funnels energy into producing new growth and more flowers, although it is not necessary to prune for flowering.

On some cultivars, pruning to remove spent flowers will encourage new growth and an additional blooming in late summer.

To develop a tree, select several evenly spaced shoots growing from ground level as the primary trunks. Remove branches from these shoots approximately halfway up. As the plant matures additional lower branches should be removed until the canopy is 3-4 feet above ground level. It may be necessary to remove suckers from the base to retain a tree shape. Some landscapers advise applying a synthetic plant growth regulator (naphthalene acetic acid) to prevent suckers from re-growing.

Should you wish to grow your crape myrtles as compact shrubs, prune the stems to approximately six inches above the ground. Severe pruning will not kill or damage a healthy plant, but make sure that pruning is done before spring growth begins.

To achieve a medium sized shrub, prune moderately by removing twiggy growth smaller than a pencil. Indiscriminate topping of crape myrtles to obtain a uniform height is widely practiced, however it is not recommended. It is better to utilize the appropriately sized cultivar for the area in which it is to be planted.

Always remember that new growth will emerge 3-4 inches below the cut. Do not cut large limbs back as this will encourage an overabundance of new growth near the cut resulting in unattractive clusters of vigorous growth along the stalk. In addition, this will cause them to be more vulnerable to aphids. This type of extreme pruning, shown at left, is often called "Crape Murder."

Read more about Pruning:
Aggie Horticulture
Gardening with Skip
CrapeMyrtles.com
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A general garden fertilizer such as 9-8-8, 10-10-10 or 12-4-8 is ideal for crape myrtles. Apply one teaspoon of fertilizer monthly from March through August around the perimeter of a newly planted small specimen. A larger broadcast area in spring will benefit more established plants. Avoid over fertilization as it will result in excess growth and a reduction in flowers. Just before it rains is the best time to fertilize. In dry weather, water-in fertilizer after application. There is no need to remove mulch.

Semi-hardwood cuttings removed during the growth season can easily be propagated. Be sure to make your cuttings from new growth and leave 3 to 4 nodes and several leaves on each cutting. As a general rule, rooting hormone is not necessary. Cuttings should be placed in a well-drained rooting medium in a shaded area. Retain moisture by placing them in a clear plastic bag. Cuttings should begin to root in three to four weeks.

To start cuttings in an outdoor bed, thoroughly prepare the soil. Cultivate the soil 10 to 12 inches deep and then add 4 to 5 inches of organic material mixed well into the soil. Peat moss, leaf mold or pine bark works well. Insert cuttings ½ their length into the soil and 6 inches apart. Mist regularly and mulch with an additional 2-3 inches of organic matter.

Young plants can be moved to a permanent location during fall or winter.

Crape myrtle is susceptible to several diseases including powdery mildew. This will normally develop in late spring and fall with warm days and cool nights with high humidity. A powdery white mold coats young shoots and flowers. Flower buds may not open and severely infected leaves and buds often drop prematurely.

Read more about diseases:
Clemson University Extension
Mississippi State Extension (.pdf file)
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Leaf spot caused by Cercospora lythracearum fungus is the other most damaging disease to crape myrtles. Dark brown spots develop on lower leaves and work upward in the humid weather of summer. Sometimes even one spot will cause leaves to drop on certain cultivars and can cause premature defoliation before the first frost.

Both of these diseases can be controlled by applying fungicides when they are first noticed. Be careful to follow directions on the container. However, the best prevention is to plant disease resistant crape myrtle cultivars for low maintenance landscapes.

Sooty mold is usually caused by the excretions of insect pests such as aphids on crape myrtle. The dark brown or black coating on stems and leaves can be removed by rubbing. This mold seldom causes serious damage but can reduce the vigor of a plant. Again the best protection is to grow resistant plants.

The Crape Myrtle Trails of McKinney, TX
Auburn University College of Agriculture
The United States National Arboretum
U. of Florida College of Agriculture
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