Been there done that with brugmansia. I got rid of mine because every year it was the same fight. If I had a greenhouse I would put it in there because it is a very interesting and good smelling plant. One year I put the hose nozzel on mist and propped it up high over the plant. That got it through a night or two of cold. Once in a while it would bloom before frost hit; people would ask me what is that plant because it is so exotic looking. I brought some plants in and have escorted several harmless spiders outside and squashed some bugs.