Species belonging to the Bougainvillea genus are subtropical to tropical woody vines that tend to be thorny and evergreen. Native to South America, bougainvilleas are flowering plants that enjoy high heat and low to moderate moisture. Bougainvilleas grow as perennial plants in mild-winter climates and are hardy down to only USDA Zone 9, where temperatures rarely dip below 25 or 30 degrees Fahrenheit. In colder regions, bougainvilleas are grown outdoors as annuals or kept indoors during the colder months. Bougainvilleas are beloved for their flowers and brightly-colored, large bracts, some of which are fragrant.
Keep the bougainvillea in a spot that receives at least five hours each day of direct, full sunlight. Maintain air temperatures around the bougainvillea of no colder than 60 degrees Fahrenheit.
Water the bougainvillea deeply to soak the soil down to and around the roots whenever the top layer of soil dries out or when the plant begins to wilt during dry spells. If you're growing the bougainvillea in a pot, water until it begins to drain from the bottom of the pot and never allow the plant to sit in waterlogged soil.
Feed the bougainvillea once or twice each month while the plant is actively growing with a 6-8-10 NPK formula fertilizer that contains micronutrients like iron. Follow the dosage instructions on the label and fertilize the bougainvillea at half the normal rate during non-blooming months when temperatures are cooler.
Prune the bougainvillea's stems back to promote a bushier shape and to remove the growth that has already produced flowers. Perform any hard pruning in early summer and trim lightly to maintain the bougainvillea's size throughout the rest of the summer months.
Pinch back the bougainvillea's soft stem tips to encourage a fuller form and healthy branching when the plant is young. Pinch back about ½ inch of the new growth tips after the plant finishes blooming.