Planting Site: A sunny location where the air moves freely will help limit powdery mildew and other diseases.
Soil: Provide moist, moderately fertile, well-drained soil.
Pruning: Crepe myrtles bloom on new wood, so prune them in late winter or early spring to increase next summer’s flower production. Pruning off old flowers in summer before they set seed may produce a second wave of blooms. Except on dwarf types, remove side branches on trunks up to the 4- to 5-ft. level. To reveal attractive trunks, also remove branches growing inward toward center of plant.
The crepe myrtles are among the most satisfactory of plants for the South: showy summer flowers, attractive bark, and (in many cases) brilliant fall color make them year-round garden performers. Long, cool autumns yield the best leaf display; sudden frosts following warm, humid fall weather often freeze leaves while they’re still green, ruining the show.
Most crepe myrtles in gardens are selections of L. indica or hybrids of that species with L. fauriei. The latter species has attracted much notice for its hardiness and exceptionally showy bark. Queen’s crepe myrtle, L. speciosa, grows only in the Tropical South.
All crepe myrtles bloom on new wood and should be pruned in winter or early spring. On large shrubs and trees, remove basal suckers, twiggy growth, crossing branches, and branches growing toward the center of the plant. Also gradually remove side branches up to a height of 4–5 ft.; this exposes the handsome bark of the trunks. During the growing season, clip off spent flowers to promote a second, lighter bloom. Also prune dwarf forms periodically throughout the growing season, removing spent blossoms and thinning out small, twiggy growth.
Crepe myrtles are not usually browsed by deer.
Types of Crepe Myrtle Trees
Japanese Crepe Myrtle. L. fauriei. Native to Japan. Tree to 20–30 ft. tall and wide, with erect habit and outward-arching branches. Light green leaves to 4 in. long and 2 in. wide turn yellow in fall. Especially handsome bark: the smooth gray outer bark flakes away to reveal glossy cinnamon brown bark beneath. Small white flowers are borne in 2- to
4-in.-long clusters in early summer; often blooms again in late summer. Resistant to mildew and best known as a parent of hardy, mildew-resistant hybrids with L. indica, though it is handsome in its own right. ‘Fantasy’, with even showier bark than the species, has a vase form―narrow below, spreading above. ‘Kiowa’ has outstanding cinnamon-colored bark.
Crepe Myrtle. L. indica. The premier summer-flowering tree of the South. Tolerates heat, humidity, drought; does well in most soils as long as they are well drained. May be frozen to the ground in severe winters in the Upper South, but will resprout. Gardeners there should plant cold-hardy selections such as ‘Acoma’, ‘Centennial Spirit’, and ‘Hopi’. Variable in size (some forms are dwarf shrubs, others large shrubs or small trees) and habit (spreading or upright). Dark green leaves are 1–2 1/2 in. long and somewhat narrower, usually tinted red when new; they often turn brilliant orange or red in fall. Crinkled, crepe-papery, 1- to 1 1/2-in.-wide flowers in white or shades of pink, red, or purple are carried in dense clusters.
Trained as a tree, it develops an attractive trunk and branch pattern. Smooth gray or light brown bark peels off to reveal smooth, pinkish inner bark; winter trunk and branches seem polished.
Mildew can be a problem. Spray with triforine (Funginex) before plants bloom, or grow mildew-resistant hybrids of L. indica and L. fauriei. Almost all selections with names of Native American tribes, such as ‘Hopi’, ‘Miami’, and ‘Zuni’, are mildew resistant.
Queen’s Crepe Myrtle. L. speciosa. Zones TS; 12–9. Tree to 25–30 ft. tall, 15–25 ft. wide. The showiest and most tender of the crepe myrtles, displaying huge clusters of white, pink, lavender, or purple flowers in June and July. Individual blossoms reach 3 in. across. Large leaves (8–12 in. long, 4 in. wide) turn red in fall. Smooth, mottled, exfoliating bark. Rank grower; annual pruning in winter is especially important to control size and form.
Crepe Myrtle Pruning Tips
Don’t chop your large crepe myrtles down to ugly stubs each spring just because your neighbors do. This ruins the natural form and encourages the growth of spindly, whiplike branches that are too weak to hold up the flowers. To reduce a crepe myrtle’s height, use hand pruners or loppers to shorten the topmost branches by 2–3 ft. in late winter, always cutting back to a side branch or bud. For branches more than 2 in. thick, always cut back to the crotch or trunk. Don’t leave big, ugly stubs.