Bougainvillea is a perennial vine that can grow to 30 feet, depending on the variety. It needs full sun, is root hardy and will regrow in spring. Its bracts "bloom" May-December on new wood. Heavy pruning, lack of water and fertilizer low in nitrogen encourage blooming.
Q: When can I prune my bougainvillea?
A: You can prune hard most any time. I've known gardeners to
prune bougainvillea to the ground, but you might remove 1/3 to 2/3 of the stems instead. Then snip the branches in the future to keep it in bounds.
If a freeze threatens, protect tender new growth and mulch the roots.
Many grow bougainvilleas in containers and prune hard in winter before bringing the potted plants indoors for protection. Others prune hard in spring and then prune back to the edge of the container/basket after each flowering cycle to shape the plant. Or they pinch the soft tips after a flowering cycle to encourage branching.
Bougainvillea blooms on new wood. The more you prune and pinch to encourage growth, the more color you get.
Q. How do I prune my bougainvillea?
A. Bougainvillea is a vine that drops its leaves in winter and puts on new foliage when warm weather returns in spring. Some grow this plant in containers or baskets; others grow it as a large vine with support.
You can prune the plant when and how much you like. Pinch the soft tips of young plants to promote a bushier form. After flowering, prune branches back hard, to the edge of the container or basket, to shape.
Q: I didn't cover my bougainvilleas during the freeze. Should I prune them back now or wait until the threat of freezing temperatures is past?
A: I like to wait to prune, since it usually means I start the growing season with a larger plant. Freeze-damaged wood provides some protection for live wood further down the stems. If you don't care about this, you can prune now; but mulch well to protect the roots during future cold snaps.
Q: When can I transplant a bougainvillea?
A: It is safe to transplant in winter if it can be protected during a freeze. To play it safe, transplant in spring. Be careful with the fragile roots. Mulch.
Q: Why won't my bougainvillea bloom?
A: Bougainvillea, many say, color best when somewhat pot-bound. Those planted in the garden have plenty of space for roots to stretch, giving you lots of green growth. But eventually it should color.
Most agree that the bracts color best when the plants are subjected to dry periods.
To force bougainvillea into bloom for nursery sales, growers often withhold water for up to three months. The poor plant thinks it's dying. Then the grower waters heavily, the plant thinks it has one last chance to propagate itself, so it produces a volume of flowers to launch seed for future plants.
To encourage flowering: Water and fertilize, but not heavily, during spring and summer. If a plant wilts because it is too dry, give it some water. Use a high-potash fertilizer, such as a
bougainvillea fertilizer, rather than a high-nitrogen fertilizer.
Apply about a tablespoon of hibiscus fertilizer every three to four weeks. Or use a specially formulated bougainvillea fertilizer. A tablespoon of Epsom salts when you fertilize can be beneficial, too.
Stop fertilizing during late fall and winter; water only when you see a slight wilt. Large, container-grown plants can be pruned so they can more easily be stored in the garage to protect the roots from below-freezing weather. Or prune plants in early spring. Return potted bougainvillea to a full-sun location in spring and resume monthly fertilizing.
Prune long trailing stems back 20-30 inches to encourage more color — the flowers and bracts form on new wood.
Plants will flower for weeks, then rest before blooming again.
Some
bougainvillea varieties benefit, too, from long nights and short days and bloom best in fall. Those gardeners who have exhausted all tricks to encourage color should make sure the reluctant plant is not exposed to light at night. You might just have a variety that is a fall performer.
What you see aren't actually the flowers. You see the colorful bracts or petal-like leaves. They hold their color for an extremely long time, which is why they are such great sale plants.
