Information on the Tibouchina Shrub

Types of Tibouchina

• Several varieties of tibouchina are available at commercial nurseries. Tibouchina urvilleana, also called Tibouchina semidecandra, grows around 15 feet long, with vining stems and large simple leaves. Although it has a natural mounding form, this plant can tolerate pruning and makes an attractive compact shrub. Tibouchina heteromalla grows around 6 feet tall, while Tibouchina granulosa or purple glory tree reaches heights of approximately 20 feet. This plant has an irregular crown and dark green leaves. All three species yield bright purple blossoms.

Cultivars

• Several Tibouchina cultivars include Tibouchina urvilleana "Athens Blue" or Tibouchina urvilleana "Compacta," a variety with a compact mounding or rounded form that usually grows to around 7 feet tall and produces showy purple flowers; Tibouchina "Noelene" yields white blossoms that deepen to pink as the flowers mature; Tibouchina leopidota "Alstonville" can be cultivated as either a small tree or a shrub; and Tibouchina granulosa "Kathleen" is a pink-blossoming variety that can grow into a tree.

Care and Cultivation

• Tibouchina shrubs are tropical plants that thrive in U.S. Department of Agriculture hardiness zones 8 through 12 depending upon the cultivar and variety. They freeze and die in cold weather, but will usually send up shoots again in the spring. These plants prefer well-drained, nutrient-rich moist soil and can tolerate either full sunlight or partial shade. If you grow them indoors or in a greenhouse, keep the temperatures between 50 and 75 degrees Fahrenheit and feed them twice a month using a diluted water-soluble fertilizer.

Benefits and Liabilities

• Tibouchina shrubs are generally healthy and low-maintenance once established, with moderate tolerance for drought. Some varieties may be weedy and require regular pruning to develop an aesthetically pleasing form. Insect pests such as scale, spider mites and mealybugs occasionally attack tibouchina shrubs, causing stunted growth, discoloration and leaf loss. Mealybugs and scale exude large amounts of a sweet liquid called honeydew that collects on the foliage. The honeydew attracts an unsightly black fungus called sooty mold.