Few vining plants can top a bougainvillea (Bougainvillea spp.) for exuberant, sprawling growth and masses of vividly colored flowers. Usually an evergreen plant, the bougainvillea does especially well in Florida, where it handles hot, sunny days well and thrives with only a bit of special attention now and then. A tropical plant, it grows outdoors year-round in U.S. Department of Agriculture plant hardiness zones 9 through 11, which includes all but the coolest, northern parts of Florida.
The Best Environment for Bougainvillea
The bougainvillea is a woody vine that can reach a height of 30 feet and can spread up to 40 feet, depending on the variety, so space plants 30 to 40 feet apart. The vine does best when it gets full sun for most of the day and needs at least six hours of sun daily to flower. It tolerates high Florida temperatures well, thriving in daytime heat as high as 95 degrees Fahrenheit. The plant requires nighttime temperatures that stay above about 65 degrees.
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If you live in an area that's prone to cool fall or winter nights, set up a bougainvillea trellis or other support on a south-facing wall of a building, or let the plant cascade over a warm, stone or brick wall. If you live in USDA zone 8, which includes parts of northern Florida, you can grow bougainvillea in a pot or hanging basket; keep it on a sheltered porch or patio and bring the plant indoors if frost threatens.
Soil and Water for Bougainvillea
The bougainvillea plant grows best in fertile, loamy soil but can tolerate any type of garden soil, provided it's well-drained. It continues putting out new growth when its soil is kept evenly moist, with slight drying between waterings. Check the top 2 or 3 inches of soil with your fingertip to determine when to water, and don't allow soil to stay soggy because this can promote root rot and also cause leaves to fall. If you're growing bougainvillea in pots, always assure that the potted plant has drain holes and never keep it in a water-filled saucer. Avoid watering on cool nights, which can also lead to fungal problems.
Feeding and Pruning Bougainvillea
To sustain growth, it's important that a bougainvillea has nutrients available at all times, so fertilize the plant regularly. A slow-release formula such as 18-6-12 that also contains iron and micronutrients is a good bougainvillea fertilizer. Apply it once every six weeks, or immediately after each flush of new blooms appears. Use it at a rate of 1/2 cup per 10 square feet, or 4 teaspoons for a 1-gallon container, but check your product label for additional directions and water it in well.
A bougainvillea grows naturally as a climbing vine, twining around a fence or other support, but regular trimming promotes flowering because buds only form on new growth. You can also trim the plant into a shrubby form by cutting back its vines. For a young plant, pinch back growing tips to promote branching; trim back older vines to the desired length after each blooming cycle, or about every six weeks. The plant has sharp thorns, so wear protective gloves when pruning, and wipe your blades with rubbing alcohol between each cut to prevent the spread of disease.
Potential Problems With Bougainvillea
Bougainvilleas can bloom year-round in Florida but usually have their peak flowering in fall and winter, producing blossoms attractive to both butterflies and hummingbirds. If blooms are slow to appear, cut back on fertilizer and allow the plant to dry out more fully between waterings.
This plant if usually free of disease problems when grown under proper conditions in well-drained soil. It is susceptible to damage from a nocturnal caterpillar that eats its leaves and can do some damage, although plants normally survive and regrow well. You can control the pest by spraying with a Bacillus thuringiensis, or BT, spray, diluted at a rate of 4 teaspoons per gallon of water, but check your product label for additional directions.