Answer: Place bougainvillea in a location with lots of light if you want them to be leafy and green all winter. Take extra care not to keep them too wet or they will rot. Another approach is to prune them back and place them in a cold--but not bitterly cold--spot and let them go dormant. That might be a protected garage or such an area. They should be able to take it down to about the upper 20's or 30F without being killed. Then in spring move them to a warmer spot and let them resprout and grow.
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