A purple crepe myrtle is a deciduous shrub or small tree that produces showy flowers in mid to late summer and early fall. The botanical name for this ornamental is Lagerstroemia indica purpurea, reflecting the color of the stunning blooms that appear on the ends of the branches. A purple crepe myrtle generally reaches a height at maturity between 15 and 20 feet (4.6 to 6.1 meters) with a spread of 6 to 8 feet (1.8 to 2.4 meters), although a dwarf purple crepe myrtle cultivar is available that only attains a height of 3 to 6 feet (0.9 to 1.8 meters). These plants work equally well in both formal and informal gardens.
The individual purple crepe myrtle flowers that combine to form the showy clusters aren’t uniform in color. They range from pale shades of lilac to deeper purple hues. The leaves start out with a bronze coloration when they first unfurl, turn green throughout the growing season, then transform into attractive shades of red, orange, or yellow in autumn. After the leaves fall, the fruit remains as small brown pods.
A purple crepe myrtle is a fast-growing species that can be used as a decorative hedge for privacy during the growing season. It also looks stunning as a single specimen in the garden with ground cover planted around its base. This plant thrives in full sun and is a popular plant in the southern United States because it is heat- and drought-tolerant.
There are a few other varieties of purple crepe myrtles in the Lagerstroemia indica species besides the purpurea. Twilight is a type of crepe myrtle known for its long-lasting, deep purple blooms that appear in the spring and continue into October. The reddish orange leaves of the twilight crepe myrtle in the fall add another season of beautiful color to the landscape. This species is one of the larger crepe myrtles that should never be planted close to a building or power line.
The Catawba crepe myrtle is another species that provides deep purple blooms for three months a year. It has a rounder growth pattern than other crepe myrtles, reaching a height of 15 feet (4.5 meters) with a spread of around 14 feet (4.2 meters). Catawba crepe myrtles are medium-sized and work beautifully in some of the smaller areas that the twilight variety would overwhelm. Zuni is another purple crepe myrtle that sports flowers in lighter shades than the twilight or Catawba species. Its flowers are closer to a lavender hue, and also have a long growing season, blooming throughout the summer and into fall.