Bougainvillea Pruning Tips: What You Need to Know

1st, I’ll talk about the big pruning which determines which shape & size the bougainvillea would be for the season. This depends on your climate zone. In Santa Barbara (along the California coast zone 10a) I did that pruning in late Jan through mid-Feb, depending on when I got around to it.

Here in Tucson (the Sonoran Desert zone 9a) the days can be warmer but the nights are colder. Because we experience a handful or 2 of evenings dipping below 30F, I wait until mid-March through early April to do the big pruning on my bougies.

In addition, I prune after each big flowering throughout the season. I pruned more extensively in SB than here in Tucson because the temps don’t start cooling until the end of Sept. When the temps are over 100F, I pretty much leave my bougainvilleas be except for a little tip pruning. Pruning in that heat isn’t good for the plant, nor for the pruner!

I touched on that above. In Santa Barbara I pruned my bougainvilleas 4 or 5 times during the season whereas as here in Tucson, it’s more like 2 or 3.

This also depends on what size, shape, & form your bougainvillea is. For example, a bougainvillea tightly shaped is going to require pruning more often than 1 growing in a more free form fashion.

It depends on what type of bougainvillea you have & what shape you want it to take on. Mine which grew up & over my garage in Santa Barbara was Bougainvillea glabra & it reaches 20’+ tall.

I pruned it down to 2 major trunks & trained it to grow up the right side of the garage. I attached a metal trellis to the center top of the garage & trained it to grow across the entire span. It was work, but very well worth it in the end.

My Bougainvillea Barbara Karst (which reaches 25′) next to my garage here in Tucson never gets that tall because a freeze usually knocks it back. When I moved into this house, it had been pruned as a 5′ hedge & never flowered.

I let it grow out, opened it up, & now it grows in an open shrub form. It blooms on the regular which is what we all want. And, I keep it under 8′ tall so it’s easier to prune.

I do the big pruning in late winter/early spring. Throughout the season, I prune to shape & encourage the next round of blooming.

In fall, I lightly prune to shape so it isn’t a mess going into winter. Tucson can get its 1st freeze in late Dec. so I make sure I do that pruning by mid-Nov. In coastal California where a freeze is rare, you can do that pruning into early to mid-Dec.

In my opinion, yes. I’ve seen bougainvillea which hasn’t been pruned at all & it’s a ratty mess. You don’t need to cut it back hard unless it’s severely overgrown. Otherwise, a light or moderate pruning will do.

Saving the best for last! It’s important to know that bougainvillea blooms on new growth. If you see a tall, overgrown, unpruned bougie that’s why all the blooms are at the very ends.

Bougainvillea needs at least 6 hours of sun to do a full out bloom. Plus, they love warmth so if it’s not getting these 2 things, the bloom won’t happen or will be sparse.

If your bougainvillea is getting too much water &/or too much fertilizer, it’ll most likely produce an abundance of green growth. Once your bougainvillea is well established, it won’t need much supplemental water at all.

So, even a tip prune (pinching) will encourage new growth & hence blooming. And that’s why you want to prune or lightly prune your bougainvillea after each big round of flowering. It’ll bring on new growth & those blooms we all want.