How to Encourage Bougainvillea to Bloom

Bougainvillea flowers are actually modified leaves, called bracts.

Bougainvillea are woody vines that bloom with a profusion of colorful flowerlike bracts in the summer. The plants are South American natives that can be grown outdoors as perennials in U.S. Department of Agriculture planting zone 10 and zone 9 with winter protection. Gardeners in cooler climates can enjoy the beauty of bougainvillea as a houseplant. Wherever they are grown, you need to meet the plants cultural requirements for best bloom.

Difficulty:

Moderate

Instructions

Things You'll Need

• Pot (optional)
• Balanced fertilizer
• Pruning shears

1. Plant your bougainvillea where gets at least five hours of sun a day -- the more the better. Afternoon sun is wonderful. They love warm climates as well. In partial shade you'll get growth, but no flowers.

2. Pot bougainvilleas in an appropriate container. Anything from a 1-gallon to a 5-gallon pot is fine. Try not to use a black pot in direct sun -- that's a little too much heat. Be aware, however, that in order for them to grow like crazy and cover your patio wall, you'll need to put the plant in the ground.

3. Make sure the pot has good drainage and a hole at the bottom. Styrofoam peanuts are effective for drainage in the bottom of the pot and keep the pot from being too heavy with potting soil.

4. Keep potted bougainvillea pot-bound until the roots have replaced all the soil. If you're going to re-pot and not transplant it into the ground, put it into a pot just next size up. For example, if the plant has been growing in a 6-inch pot, then you re-pot into an 8-inch pot.

5. Fertilize potted bougainvillea, as they will eventually exhaust the nutrients in the soil. They like a balanced fertilizer, a 20-20-20 mix is good (that's nitrogen, phosphorus and potassium). The nitrogen should be in the form of calcium nitrite. Use a soluble fertilizer mixed in with their water.

6. Water bougainvillea enough to really soak the soil. For potted plants, the water should be enough to run out the hole. Don't let the plant sit in a puddle, though, they hate wet feet. Let the soil on the top dry out before watering again. Don't water on a automatic schedule -- let the plant tell you when it needs water. In warmer months, it'll be more thirsty.

7. Prune bougainvillea at any time of year -- it has a bloom cycle followed by a rest period that does not depend on pruning. Remove new, tender branch tips to promote side shoot branching. Prune most of a branch from the plant to control the growth of stems that have gotten out-of-hand, or any time you want to obtain a bushy form. For hanging baskets, cut back hard at least once a year. It doesn't harm the plant to cut back hard after each bloom cycle.

Tips & Warnings

• If you're not fortunate enough to live in a warm climate, bring 'em indoors (or at least away from frosty temps) for winter, near a sunny window. They'll go dormant, so cut back on the water Come spring, put 'em back outside in the sunshine.

• Cuttings from current-season grown can be propagated to start new plants.

• Beware of thorns.

References

• Clemson University Extension: Bougainvillea

Resources

• U.S. National Arboretum: USDA Plant Hardiness Zone Map