Question: I have a beautiful bougainvillea that has bloomed all summer. I was told that I could keep it indoors in the winter, but how?
Answer: The bougainvillea (Bougainvillea spp.) is a spiny climbing subtropical shrub that can bloom on and on for months, even all year long under very good conditions. There are more than 300 cultivars with different colors of bracts, most of which are complex hybrids between different species. You’ll see giant specimens covering entire walls in Mediterranean and tropical climates, but also potted bougainvilleas of a much smaller size (thanks to judicious pruning) sold in pots and baskets as a summer annual in colder areas.
The bougainvillea was named in honor of Count Louis-Antoine de Bougainville, an 18th century French aristocrat, navigator and explorer.
What a bougainvillea likes is full tropical sun, moderate watering (unlike most plants, it does better if you keep it on the dry side than evenly moist) and regular fertilization during its growing period. In regions with mild winters (zones 9 to 11), where it can be planted outdoors, that can sometimes be all year, but in more Mediterranean climates it will go semi-dormant and stop blooming over the winter. In temperate climates, you either have to grow it as an annual and let it die in the fall, or shelter it indoors over the winter … and keeping it alive it indoors during the dark days of winter is the subject of this article.
The true “flowers” of the bougainvillea are small, fairly ephemeral white or pale yellow trumpets surrounded by three papery bracts (double bougainvilleas have more bracts). It’s these bracts in red, purple, yellow, orange and white—and that last for months!— that give the plant its festive appearance.
Keeping It Alive
Make sure you bring your bougainvillea indoors before frost hits. True enough, you’ll read that it’s able to tolerate some frost, but that’s when it’s growing in the ground … and even then, the damage can be severe. In pots, where frost can penetrate right through the root ball in no time, a serious cold snap can kill it outright.
There are two ways to keep a bougainvillea alive indoors over the winter: keeping it growing as a houseplant or forcing it into dormancy.
1. As a Houseplant
Place the plant in the sunniest spot possible, preferably in front of a large south-facing window or, better yet, in a moderately heated greenhouse or veranda with light coming from several sides. Even under these conditions, the plant will probably lose many of its leaves when you bring it in, as lighting indoors is always less than outdoors.
Things will only get worse as autumn gives way to winter and days become shorter and darker. In temperate regions, winter light is rarely sufficient for its taste. Good atmospheric moisture may help the plant to retain a few more leaves though.
Ideally, you’d lower the temperature as well to 45 °F or 50 °F (8 °C or 10 °C), but that’s not always possible in many homes. Fortunately, it will put up with room temperatures if it has too.
Your goal during the fall and winter is just to keep your bougainvillea alive, not to stimulate growth, so water very modestly, letting the soil dry out considerably before watering again. Nor should you fertilize in fall or winter: that will only stimulate weak growth you’ll have to prune off later.
2. Force It Into Dormancy
Dormancy is not a normal state for bougainvilleas. In the wild, they do best where they can grow at least a bit at all times. Still, they’ll adapt to it if necessary.
To initiate dormancy, place the plant in a cool basement, a heated garage or any other cold but frost-free spot. No light is needed: the plant will be dormant, after all. Water only enough so that the root ball doesn’t dry out completely, perhaps once or twice a month. The plant will lose all its leaves, but that doesn’t mean it’s dead.
Back to Life in Spring
With the return of longer days in March, it’s time to wake your bougainvillea up. If possible, place the plant in a sunny room and start giving it better care, especially more frequent waterings. Start fertilizing it too (any fertilizer will do), lightly at first, at about one eighth of the recommend rate, then more as it puts on more growth. The idea at this point is to give it a head start on summer.
This is also the time for a bit of pruning. Since bougainvilleas bloom on new wood, you can cut them back quite severely and that should stimulate the growth of more branches and therefore more bloom in the months to come. Besides, who has the space to allow a potted plant to produce branches 10 feet (3 m) long? However, the downside to pruning is that it will also delay blooming. A good compromise is to cut the branches back by about a third. (Note too that, during the summer months, you should also prune back any stems that are getting too long.)
If you want to repot, spring is also the right season. Note that bougainvilleas bloom best when they’re a bit underpotted … but they’re fast-growing plants: after 2 or 3 years, you’ll have no choice but to repot it.
A Summer Outdoors
As soon as the risk of frost is gone, gradually acclimatize the plant to outdoor conditions. A site in full sun is ideal. And remember to water and fertilize regularly.
Remember that bougainvilleas really aren’t good houseplants, that you only bring them indoors to keep them alive until the following summer. It’s outdoors under the intense summer sun that bougainvilleas truly strut their stuff! So be prepared to accept a rather discouraging winter appearance as the price to pay for beautiful summer blooms!
I kept my plant in in winter and flowered all winter but now it has lots of white insects on I wipe them off but they keep coming back am I doing something wrong ?
Oh dear, they would be mealybugs, so hard to get rid of! You’re not doing anything wrong: the nursery sold you an infected plant. https://laidbackgardener.blog/2018/12/14/when-mealybugs-attack/
I did not think to prune it in the summer and so now my two plants are quite leggy and taking up a lot of horizontal space! What will happen if I prune it now on bringing it indoors in late October? I have a south facing window I can keep it in, but just thought it might be nice to trim it back. If not recommended, I will wait until March.
It’s understandable that you would need to cut back an overgrown specimen. It’s “acceptable” to prune in the fall, but it may try to regrow (pruning often stimulates growth) and, ideally, you’d want the plant to stop growing. So, if you prune, be especially careful to keep the plant a bit on the dry side to discourage it from growing.
I first saw bougies growing on the wall at Mission Carmel in California. I knew that one day I’d have to get one to grow in north Arkansas in Zone 7a. I just bought a fuchsia-colored cutting online this spring. The leaves that came with it yellowed and fell off, but new ones are growing as it stays out in the sun.
I kept my boggy hanging in window in the basement after tiriminng back and it looks awesome and ready for the outdoors. Northern Iowa.
Great article. Thank you. I live in Ottawa, Canada, so lots of frost..and early. Over the past few years I have brought my bougainvillea indoors for the winter. Strangely it flowers profusely indoors once, about January, and the not at all for the rest of the year. Not even in the summer. Will keeping it dormant promote flowering in the summer? Seems like it has the seasons mixed up:)
Yes, “forcing” it into dormancy will help it get back on a more normal schedule.
I first saw a bougainvillea in Greece and fell in love with it! In some regions of Greece winter temperature is around 5 degrees Celsius. My area is 6b so planting bougainvillea in the garden is not an option. But I bought a potted one 3 years ago, then another one, I also propagated them and now I have 4. I tried to replicate the Greek climate so during summer I keep them in the garden in full sun. I dont’t pinch, I don’t prune, just let them do their thing. They’re full of flowers. In late fall, I move them to a closed terrace, unheated, where the medium temp in winter is 8-10 degrees Celsius but sometimes as low as 3 (but never below 0). They lose all the flowers and leaves at some point. In spring, when I see small leaf buds, I prune the branches back to about 5 cm, cut off alk that seem dry or crossing and when night temps are about 10 degrees Celsius I move them to the garden. First on the shaded side and later in full sun.
Congratulations! You seem to have created just the right conditions for success!