Pruning is recommended only to remove an over-density of branches and crossing limbs. Cutting off old flower heads in summer can promote a second and third round of flowering, though. Over-fertilizing creates abundant foliage at the expense of blooms. Crape myrtles are a magnet for aphids, upon whose excrement sooty mold grows. This can give the leaves a gray, sooty coating that is not harmful, but is unsightly.
Control aphids with a soapy water solution.
Moist, well drained soil. In general, trees are extremely vigorous and hardy. By cuttings from medium wood in early fall or hard wood in winter. Also by seed. Easy to root.