[Choice Maintenance]

From my experience bougainvillea enjoys stress. The reason most of your bougainvillea is reacting to sunshine is because it doesn't enjoy a lot of water and the sun will help with drying it out. Usually when green with no blooms it's a sign of excess water. I once heard a story from one of our nursery vendors that you should plant bougainvillea with half of the pot still attached to stress it out. Don't think I'll try that one though.