Bougainvilleas (Bougainvillea spp.), with their brightly colored 1- to 2-inch-long, papery bracts in red, purple, orange and pink or in simple white, make versatile plants in the warm climates of U.S. Department of Agriculture plant hardiness zones 9 through 11. In colder climates treat them as annuals or bring them indoors for winter. Plant large, spreading bougainvillea shrubs as barriers and screens in a yard. Train the vines to climb an arbor and scale a fence, or to cascade over a hanging basket on a patio. You can also grow them as houseplants.
Wear gloves when handling bougainvilleas, and plant them away from swimming pools and children's play areas. They contain sharp thorns that scratch and puncture bare skin. Some people may develop dermatitis after touching them.
Train bougainvillea vines to grow atop a straight, bare-stemmed "tree" or standard. To do this, Insert a tall stake into the center of a large pot that contains three young bougainvilleas. Braid the vines around the stake, and then carefully tie them to the stake. Trim the side branches with sterilized pruning shears as the vines grow until they reach the height you want your "tree trunk" to be. The colorful flowering vines will naturally create a weeping mass of branches at the top of the standard.
Soak pruning shears in a mixture of 1 part household bleach and 3 parts water for a minimum of five minutes to disinfect. Rinse with clean water before trimming the plant.
Train a bougainvillea as a bonsai by first wrapping the trunk with wire and then the branches with raffia and wire. Bend the branches to style the bonsai into the desired form as it grows. Check the wires every few weeks to ensure that none are too tight to cause injury to the branches. Remove the wire after one growing season by cutting away a little at a time to avoid damage to the plant. Consider literati, cascade or semi cascade styles to best match the plant's natural form. Lesser bougainvillea (Bougainvillea glabra) works well as a bonsai. This fast-growing evergreen grows outdoors in USDA zones 9 through 11, and can also be grown in the lowest part of USDA zone 8 with protection from temperatures that fall below 32 degrees Fahrenheit.
Plant a bougainvillea indoors in good potting soil inside a 5- to 10-gallon container or a hanging basket of at least 12 inches in diameter. Set the bougainvillea where the sun shines for a minimum of half of the day. Prune to maintain the desired shape and re-pot the plant once a year.
Use only containers with drainage holes.
- 'Scarlett O'Hara' bougainvillea (Bougainvillea 'Scarlett O'Hara') flaunts clusters of dark magenta-red flower bracts in summer. It is evergreen and reaches a length of 20 to 30 feet. This variety is hardy in USDA zones 10 through 11.
- 'Mary Palmer's Enchantment' bougainvillea (Bougainvillea 'Mary Palmer's Enchantment') produces huge flower bracts in pure white in summer. It is evergreen and grows 20 to 30 feet long in USDA zones 10 through 11.
- 'Cherry Blossom' bougainvillea (Bougainvillea 'Cherry Blossom') sports dainty, rosy-pink circles of double flower bracts with a white center that remain on the vine longer than other varieties. It blooms in summer and reaches 20 to 30 feet in length. This cultivar is hardy in USDA zones 10 through 11.
- 'Rosenka' bougainvillea (Bougainvillea 'Rosenka') displays vivid gold bracts that bloom profusely from spring through summer and turn a pink color when mature. This compact shrub grows to a height of 1 to 2 feet and width of 3 to 4 feet and is hardy in USDA zones 10 through 11.