Though it's nothing a busy mom can't handle, bougainvillea (Bougainvillea spp.) does appreciate changes in its watering schedule depending on the time of year. A graceful flowering shrub, the bougainvillea’s bright bracts in shades of pink, purple, red and yellow are often confused with its flowers. Those are small and white, clustered in groups of one to three and contained within the colorful, papery bracts.
A native of South America, bougainvillea are winter hardy in U.S. Department of Agriculture plant hardiness zones 9 through 11. It grows in a scrambling habit to between 15 and 40 feet in height and width. In areas outside its hardiness range, it is often grown as an annual or as a container plant, where it can be moved indoors during the colder weather. It takes well to pruning, which is often necessary to preserve an attractive shape.
Though suited to hot, dry climates and quite drought tolerant, bougainvillea still appreciates regular watering. Give it as much as it needs to keep it from wilting. During the hottest part of the year, this may mean watering it once or twice per week. In the winter, when bougainvillea is dormant, move it into a protected area if there is any chance of outdoor freezing, and reduce watering to light applications once a month.
To Induce Flowering
If your bougainvillea blooms sparsely, you can try a number of things. First of all, remember that bougainvilleas flower mainly in the fall, so if it is any other time of year, don’t worry too much about it. Secondly, it needs full sun -- eight to 10 hours of direct sunlight -- to bloom well. If neither of these is an issue, try reducing its water. One of the best ways to induce flowering in bougainvillea is to withhold water, because drought stress will often encourage the plant to bloom. Give it just enough to perk it back up again when it wilts, but no more. Don’t try this unless you have to, however: in the right site, bougainvillea should flower well even with plenty of water.
Don’t try to induce drought stress during the hottest part of the year. For one thing, that’s likely to be summer, which is not the bougainvillea’s natural flowering time anyway. For another, although the bougainvillea is tolerant of hot, dry weather, you don’t want the plant to get too wilted. Overly wet soil can be a problem too, however; only plant bougainvillea in well-drained sites, where sogginess is never a problem. Otherwise root rot may become a problem.