Temperature: Being a warm weather plant, they must be provided winter protection. They can usually tolerate die back from a freeze, but will withhold blooms for awhile.
Watering: Sparse to light watering and good drainage.
Feeding: Fertilize once in the spring with a low nitrogen fertilizer and maybe once again in the fall. The old established method of forcing flowers is to withhold water to a point of causing severe stress to the plant. Research at the University of Florida has found that plants flower best when given high nitrogen fertilizers and short day lengths (15 hours of darkness within ever 24 hour period).
Pruning and wiring: The bougainvillea takes well to pruning; a useful attribute in styling bonsai. Because bougainvillea generally blooms on new growth, each branch, as blooms begin to fade, should be cut back to a point somewhat shorter than the desired length. Seal all cuts to prevent rot. If rot is detected on a collected specimen, cut it out completely.
Propagation: Bougainvillea may be grown from air layers, root cuttings and branch cuttings. Young shoots, a few inches in length, should be placed in sandy soil with bottom heat and moisture. Half-ripened or old wood cuttings in six to twelve inch lengths may be rooted April to June.
Repotting: Repot in Spring. Do not prune the roots too severely.