The mere mention of ‘bougainvillea’ can send many gardeners into an immediate state of panic. And fair enough to… I’ve had my fair share of bad experiences and lacerations in dealing with them, mainly in a past life as professional gardening contractor where I’ve been asked to tame yet another bougie gone wild. But it doesn’t have to be this way, because with regular light pruning and training, it’s quite easy to maintain a bougainvillea to the size and shape you want, and when you do you’ll be rewarded with a most colourful and hardy performer.
It’s not one for lazy gardeners, that’s for sure. Ignore it and it will soon become a big problem. The normal pruning required is not a lot of work – if you are the type who is prepared to trim a hedge or prune a few roses on a regular basis, then you’ve got what it takes to properly care for a bougainvillea.
The key to training and pruning them is to understand their growth habit. Bougainvilleas are programmed to climb; that’s why they produce such thick stems with large thorns that are designed to hook into things as they reach towards the light. Once they get there, they start to produce much shorter, less menacing growth on which their flowers and colourful bracts are formed.
If you do nothing, they will continue to grow and flower beautifully; however, eventually they may end up a rampant overgrown mess, forcing you to make the inevitable decision to cut them back hard. This is the big mistake.
Hard pruning normally results in an eruption of, long, wild, thick, thorny and vigorous shoots as the plant aims to once again reach for the light and re-establish its framework. The better approach – once you’ve trained established your climber to the size and shape you want – is to just keep clipping the tips of the shorter bushier growth straight after each flush of blooms has finished. These lighter cuts respond with more of the shorter compact growth we want on which a gorgeous succession of blooms will form.
I’ve seen this technique applied successfully time and time again where bougainvillea has been trained as a colourful hedge, topiary or as a hardy compact potted display. The most impressive is this gnarly specimen (pictured) I spotted in Lismore northern New South Wales that has been beautifully maintained and flowering almost continuously for over 80 years.