Most crepe myrtles planted today are selections of L. indica or hybrids between this species and L. faurei. New selections pop up all the time. One thing we've learned over the past two decades is that the mature size of many selections, particularly those named for tribes of Native Americans, such as 'Natchez,' grow bigger than first advertised. When planted in small yards or near the house, they may quickly outgrow their welcome, resulting in a winter-spring pruning ritual known as crepe murder, in which innocent trees are chopped back into ugly, knuckled trunks. (See Don't Commit Crepe Murder on p. 399.)
Fortunately, many smaller selections don't get too big and need little, if any, pruning. Mature size is so important that our revised chart (pages 397399) now groups popular selections into dwarf (25 ft. tall), short (610 ft. tall) medium (1120 ft. tall), and tall (2150 ft.) categories. Use dwarf kinds in containers, mixed borders, and masses. Use short types in containers, shrub borders, or near the house. Use medium types as small shade trees, street trees, or for screening. Give tall types lots of room and don't plant near the house. One 'Natchez' is plenty for a 900-square-ft. lawn.
Consider these four factors before buying a crepe myrtle.
What color are the flowers?
How big will it grow?
Is the yard sunny enough? (The more sun, the more flowers.)
Is it cold-hardy enough? (important if you live in the Upper South, USDA 6)
L. faurei. JAPANESE CREPE MYRTLE. Upright tree to 2550 ft. tall with arching branches. Native to Japan. Seldom grown in the South. Main contribution has been imparting mildew resistance and showy, flaking, cinnamon-brown bark to hybrids. Light green leaves to 4 in. long and 2 in. wide turn yellow in fall. Small, white flowers in 4-in. clusters appear in early summer. 'Fantasy' grows quickly to 50 ft. 'Kiowa' grows 30 ft.
L. indica. CREPE MYRTLE. This species was first introduced into the U.S. from China in the early 1800s by famed botanist Andre Michaux in Charleston, South Carolina. Grows to 25 ft. tall and wide. Dark green, oval leaves, about 2-in. long, turn bright orange or red in the fall. Showy, 612-in. clusters of crinkly pink, red, lavender, or purple flowers in summer. Smooth gray or light brown bark peels off to reveal polished inner bark. Older selections plagued by powdery mildew are not listed here.
L. speciosa. QUEEN'S CREPE MYRTLE. Zone TS; USDA 10-11. This is the showiest and least cold-hardy of the crepe myrtles, forming a rounded tree 4050 ft. tall. Magnificent clusters of pink, lavender, or purple flowers up to 3 in. across weigh down the branches in summer. Large leaves, 812 in. long and 4 in. wide, turn red in fall. Smooth, mottled, exfoliating bark. Native to Old World tropics.
Crepe myrtles bloom on new growth and should be pruned in late winter or early spring. Dwarf and short types need only minor, cosmetic pruning. On medium and tall types, prune to a tree form. Remove suckers at the base, twiggy growth, crossing branches, and branches growing toward the center of the plant. Also gradually remove side branches on main trunks up to a height of 45 ft. The tree should be open enough that a bird could fly through unimpeded. This exposes the handsome bark and also improves air circulation, making leaf diseases such as mildew and leaf spot less likely. Pruning off spent flower clusters (if you can reach them) in summer results in a second flush of blooms. If your soil is sandy or poor, give newly- planted crepe myrtles a drink of liquid fertilizer every 2 weeks in summer. After its first year in the ground, crepe myrtle needs no fertilizing.