Tibouchina urvilleana is in the Melastomataceae family, and is native to Brazil. It is also known as purple glory bush or princess flower, and received its name from the stunning flowers it produces when in bloom. Caring for the hardy tibouchina is relatively easy in the subtropical and tropical regions of the United States. Healthy tibouchina plants provide years of stunning purple blooms on evergreen foliage, and are an attractive addition to the garden.
Grow tibouchina plants outdoors in zones 8, 9 and 10, as these areas of the country are the warmest. Grow it in a container in regions that are cooler and receive consistent freezing temperatures during winter.
Select a location that receives full to partial sun during the day, and afternoon shade in regions where daytime highs can be extremely hot.
Grow tibouchina in a weed-free area that is large enough for it to reach its mature size, which can up to 15 feet high with a width of 12 feet. Do not grow this plant in crowded conditions.
Amend the planting area with a rich organic material, such as compost, peat or manure. Apply a fresh application of this material around the entire area encompassing the drip line in the spring and again in late summer. Tibouchina prefers rich soils.
Mulch the planting area to keep it weed-free and the soil moist. Apply a fresh application of cypress mulch, pine bark or decayed leaves around the growing area once per year. Adding mulch will also enrich the soil.
Water the tibouchina regularly to keep the growing area moist but not flooded. Water the plant several times per week during bouts of dry, hot weather. Water the plant once per week during winters that are moist. Do not keep the planting area flooded with water, as the tibouchina can develop root rot.
Prune to control the tibouchina’s size and shape. Prune severely, if needed, in early spring so foliage can grow back in time for the blooming season in summer. Do not prune in late fall or winter, as the plant will be more susceptible to damage from frosts or freezes. Cut plants damaged by frosts or freezes down to the ground in spring, as new growth might grow back from the roots.
Fertilize the tibouchina with a 10-15-10 or 20-20-20 fertilizer in the early spring, summer and fall. Apply around the entire drip line, not allowing the fertilizer to touch the main trunk, or it will get burned.
Protect the tibouchina from frosts and freezes by covering the plant with blankets or hanging Christmas lights on its limbs to keep it warm. Bring container-grown plants indoors during freezing temperatures.