I have two young Hirado buntan (Florida pink) trees. One, on Trifoliate, came through ~26-28 F with no signs of stress. Another, on Swingle, underwent ~75% defoliation after temperatures reached ~21 F, although it was protected by a single layer of medium-weight frost cloth over a structure made of electrical conduit, so I don't know how cold it reached inside the tent. It has since leafed out quite nicely, but I haven't noticed any blooms.