During a recent visit to botanical gardens in Florida, I was especially fascinated by one huge bougainvillea vine that had been pruned and trained to grow like a cascading ornamental tree at the edge of a koi pond. In my own chilly, northern climate, bougainvillea can only be grown as a tropical houseplant. In pots, during the summer they are allowed to climb and cover as much as they can, but each autumn they must be cut back and taken indoors to survive winter.
However, in zones 9-11, bougainvillea can grow outdoors year round, climbing and covering as much as you let it, taking only a short semi-dormancy break in early spring. Whether grown as an indoor or outdoor tropical vine, pruning a bougainvillea may seem like a daunting task, especially if you have the more common thorny types. Continue reading to learn how to prune bougainvillea.
Trimming Bougainvillea Plants
Bougainvillea is a deciduous, tropical vine, hardy in zones 9-11. In its warmest zones, it may seem evergreen and can bloom most of the year. Even in its proper zones, bougainvillea is extremely sensitive and can be nipped by frost in abnormal weather. Bougainvillea is native to arid areas and prefers a site with drier soil and full sun.
Because they love the hot, intense afternoon sun that we try to escape from, bougainvillea plants are excellent for training up pergolas. In the landscape, bougainvillea can also be trimmed back to grow as a shrubby, groundcover or foundation planting for hot, dry areas.
Of course, the problem with training, pruning or trimming bougainvillea plants is the nasty, long thorns most varieties have. When pruning anything thorny, I first put on my thick, leather rose pruning gloves. Good quality gloves usually cover the forearm as well as the hands. Wearing a long sleeve shirt while pruning can also help prevent nasty cuts and scrapes.
Good safety wear is important, but the most important thing for pruning any plant is sharp, sanitized and strong pruners. If you suspect any pests or disease problems with the plant you are pruning, sanitize pruners between each cut by dipping them in to bleach water. Make all cuts clean, as ripped and ragged edges take longer to heal over, which gives pests and disease more opportunity to infect a plant.
How to Prune Bougainvillea Plants
If you’re asking yourself, “When should I prune bougainvillea,” this really depends on where and how the plant is growing.
If grown as tropical container plants in cool climates, you will probably have to cut back plants every fall to move them to a sheltered location. In this case, there really is no right or wrong way to prune a bougainvillea. Just cut it back to a manageable size and take it indoors before there is any chance of frost in your area. The plant will probably go dormant after a hard pruning but will fill back out in spring. It’s also a good idea to treat plants for pests and diseases before overwintering indoors.
In zone 9-11 landscapes, late winter/early spring is the best time for bougainvillea pruning. Most plants will be in a semi-dormant state in mid to late winter and won’t be harmed by even severe pruning. Cut out any dead or diseased wood and also remove any crowded branches that prevent good air flow throughout the plant.
Bougainvillea plants will also tolerate shaping, light trimming and deadheading anytime of the year, but major pruning jobs should be left until the plant is somewhat dormant. Should foliage on a bougainvillea get damaged by frost, this can simply be trimmed off.