Crepe Myrtle: The Essential Southern 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, making them year-round garden performers. This moderately sized tree is available in a wide variety, so learning about the flower colors and best-growing environment will help you choose which crepe myrtle tree is best for your garden or front yard. Here's a guide to the best practices, pruning tips, and planting suggestions to help add this classic Southern tree to your growing selection.
How To Grow Crepe Myrtles
Soil and Water
After assessing the size of your crepe myrtle variety's roots, begin planting by digging a hole much larger than the plant's roots, usually three or four times its size wide. Its depth should only extend to the top of the plant's roots. You don't want any weeds or surrounding roots to compete with its space.
Crepe myrtles need partly acidic soil. Use soil to pack the roots once planted. The best recipe for success is to start with wet soil and water consistently throughout the first year of a crepe myrtle's growing season to prevent air pockets or to dry out the roots. After initial growth, you don't want to over-water plants, which can be reasonably drought-resistant, as long as it sees water about once every other week.
Crepe myrtles thrive in full sunlight, so your planting location should receive sunlight the majority of the day but also have enough room for the tree to grow to its intended height properly. Shaded areas will likely result in crepe myrtles not blooming, and partial sunlight will yield poor results. Leave enough horizontal space for the crepe myrtle's roots to expand, but be aware of the varieties' maximum height because porch ceilings or other overhanging elements could prevent its proper growth. It's best to have an unobstructed space, such as a driveway or fence line, to plant these trees because it receives sunlight while not competing for space.
Crepe Myrtle Care
Use an acid mulch such as pine bark or oak leaves for support. After its first growing season, crepe myrtles should only need fertilizer once a year—usually in spring before new growth begins.
All crepe myrtles bloom on new wood. Prune in the winter or early spring for best results. On large shrubs and trees, remove basal suckers, twiggy growth, crossing branches, and branches growing toward the center of the plant. Gradually remove side branches up to around four or five feet. This pruning exposes the handsome bark of the trunks.
When pruning a crepe myrtle, don't chop your large crepe myrtles down to ugly stubs each spring just because your neighbors do. This practice ruins the natural form and encourages the growth of spindly, whiplike branches 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 two to three inches in late winter, always cutting back to a side branch or bud. For branches more than two inches thick, always cut back to the crotch or trunk. Don't leave big, ugly stubs.
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.
Pests and Complications
Occasionally aphids, a sap-sucking insect, attack plants but are controlled through insecticides or a soap and water solution for a less harsh preventative.
Another complication occurs to trees planted in a shady area with damp or humid growing conditions. Powdery mildew is a fungus that grows on leaves, preventing new growth and damaging leaves.
Fortunately, crepe myrtles tend to be deer resistant.
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, four inches long and two inches wide, turn yellow in fall. It has an especially handsome bark—the smooth gray outer bark flakes away to reveal glossy cinnamon brown bark beneath. Small white flowers grow in two to four-inch-long clusters in early summer and often bloom 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.
Indica Crepe Myrtle
L. indica. The premier summer-flowering tree of the South. Tolerates heat, humidity, and drought, which do well in most soils as long as they are well drained. It may be frozen to the ground in severe winters in the Upper South but will resprout. Gardeners 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 around one to three inches long and somewhat narrower, usually tinted red when new. They often turn brilliant orange or red in fall—crinkled, crepe-papery, and around one to two inches wide, flowers in white or shades of pink, red, or purple appear 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 Funginex before plants bloom, or grow mildew-resistant hybrids of L. indica and L. fauriei. Almost all selections, such as 'Hopi,' 'Miami,' and 'Zuni' are mildew resistant.
Queen's Crepe Myrtle
L. speciosa. Trees grow 25–30 feet tall and 15–25 feet wide. It's the showiest and most delicate of the crepe myrtles, displaying vast clusters of white, pink, lavender, or purple flowers in June and July. Individual blossoms reach three inches across. Large leaves (up to 12 inches long and four inches wide) turn red in fall—smooth, mottled, exfoliating bark. Annual pruning in winter is critical to control size and form.