Does a Purple Glory Tree Die in the Frost?

Tropical shrubs and trees often have luxurious foliage and impressive flowers, making them attractive and versatile plants for a home garden. Although many plants in this group are extremely frost-sensitive, the purple glory tree (Tibouchina granulosa) is somewhat hardier than many other tropical plants. It grows in U.S. Department of Agriculture plant hardiness zones 8 through 12.

Purple Glory Tree

The purple glory tree, also called the princess flower or glory bush, is named for its large, bright-purple flowers. The plant grows as a sprawling evergreen shrub or small ornamental tree, depending on its pruning and training when young. It's generally about 10 to 15 feet tall and can spread to a width of 20 feet or more when fully grown. The tree has velvet-like, dark green leaves that are 4 to 6 inches long. When in bloom, the impressive flowers are carried well above the foliage on terminal stems. The purple glory tree has its heaviest bloom from May to January, but may also produce some flowers at other times of the year.


In the colder part of the purple glory tree's range, USDA zone 8, winter temperatures might fall as low as 10 or 15 degrees F for brief periods. The tree can withstand sub-freezing temperatures for several hours, but if low temperatures extend longer than this, they might damage or destroy some or all of the plant's above-ground growth. When this happens, the roots usually survive and produce new upper growth the following spring. Although the plant can re-grow quickly, it might not bloom until mid- or late-summer, since it puts most of its early-season energy into producing new stems and leaves.


If your area tends to have periods of frost in winter, choose a warm planting site near the west- or south-facing wall of a building can help protect the tree from damage during the winter. Planting the tree on a hillside, where cold air drains away to lower parts of the slope, can also help the tree survive the winter. Keeping it well-watered in fall and adding a thick layer of mulch at the base of the tree can also help the plant come through the winter well

Other Care

The purple glory tree grows in either full sun or partial shade. In a region with strong, hot summer sun, it does best in a spot that gets full morning sun, followed by light shade in the afternoon. It tolerates any type of garden soil that's well-drained, but doesn't thrive in a spot that stays wet for long periods, where it can develop root rot. If your soil is rich in clay and drains slowly, add some fine sand at planting to improve its drainage. You can prune a purple glory tree at any time to improve its shape and keep its growth under control, but trimming it immediately after flowering stimulates new growth that produces additional blossoms.

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