Jennifer Schultz Nelson
Extension Educator, Horticulture
We often forget that plants considered "houseplants" actually are outdoor plants somewhere in the world. I was reminded of this on a recent trip to San Francisco when I spied walls covered in gorgeous swaths of bright color that didn't resemble anything I'd seen growing on buildings in Illinois. I had to take a closer look!
They were Bougainvillea, plants I've grown as houseplants. In their full grown splendor, they hardly resemble those that I've tended to in pots. Native to tropical rainforest habitats, these flowering vines can reach heights of over thirty feet. San Francisco is far from tropical, but they have mild winters, allowing Bougainvillea to survive outdoors, covering walls and fences. Indoors or out, they also tolerate being pot grown in hanging baskets, or pruned into a bush or standard.
Some may assume that the bright colors of Bougainvillea are flowers. Botanically, they are bracts, which are modified leaves. The actual flowers are small, white and tubular nestled in the center of the colored bracts.
Bougainvillea flower best in high light and slight stress. Clay pots are recommended since they tend to stay drier than plastic. For Bougainvillea, being root bound with dry soil actually is a good thing!
Remember though, you can have too much of a good thing. During the hottest part of summer, Bougainvillea may need daily watering. Bougainvillea can tolerate more dryness than many plants, but prolonged lack of water will kill even the toughest of plants, as I discovered when I forgot to water my Bougainvillea for a short time this summer.With nearly constant feeding, Bougainvillea are said to flower nearly eleven months of the year. This is assuming the same intense light is available year round. In my experience, I only saw flowers in the summertime. The amount of light in an average house over the winter is simply not enough to initiate flowering. Colors range from reds, purples, pinks and yellows to white and even bicolors, some with variegated foliage.