Wow Oh Wow what color! You definitely gave me warm climate envy and your breathtaking photos are a midsummer's night Midwesterner's dream. In the Polynesia Islands gardeners place many cinder block in their garden to use as a stand for black nursery pots of bougainvillea. When I asked if they were holding areas they advised it was the way they gardened. Due to the consistent warm temperatures the bougainvillea would become out of control and rampant but this way the varieties and colors could be displayed and managed as a prized plant. I have been very successful in my attempts to over winter bougainvillea but the wretched thorns get me every time. Perhaps I should consider bonsai, yours are magnificent.