Bougainvillea is a brightly-colored vine that is often trained to grow along pergolas, fences, trellises or walls. This thorny vine gets its color from the bracts that surround small clusters of white flowers. Bracts may be magenta, purple, yellow or white. In warmer climates, the blooms may provide color all year.
Bougainvillea are traditionally known as warm-weather plants. They thrive in U.S. Department of Agriculture Plant Hardiness zones 8 and above, and in general, cannot withstand frost or freezing temperatures.
If you are growing bougainvillea in a cold region, plant it close to a dwelling or on a down slope to reduce the risk of frost. If frost threatens, cover the plant to protect it. Younger plants are more susceptible to frost damage than mature plants.
Singed or Burned Leaves
If bougainvillea is subjected to a light frost, it may survive but leaves and bracts will appear burned around the edges. If your bougainvillea survives a frost with singed leaves, it is not necessary to remove them, as they will eventually fall off. Bougainvillea regrow quickly--as long as they are not subjected to additional frosts--and the singed or burned leaves and bracts will be replaced by new growth.
Within a day after a hard freeze, the leaves of the plant may drop. If they do, this is not an indication that the plant is dead. Prune the plant back to about 6 inches from the ground and keep it warm. New growth may appear within a few weeks of warmer temperatures.
Whether the leaves fall off your bougainvillea or appear burned after a frost, the plant may have frozen and died. Frost and prolonged freezing temperatures may freeze the roots and kill the plant, as it cannot get moisture. If you prune the plant and new growth does not appear within a few weeks, it is likely dead. Dig up the plant and dispose of it.