I have a 桂花 about the size of yours. I moved it inside the house. It is still flowering now. I also have four smaller ones that I left outside hoping they will be ok for the winter. I am using them experimenting. The good thing is that so far this winter is very warm.
For your 桂花, if you can cover it with something, it may help. Good luck.
For your 桂花, if you can cover it with something, it may help. Good luck.