Last fall I double potted my four brugmansias . I put them beside my house and drive way. Our dryer vent is also on that side of the house. That side gets 6 hours of sun a day. The brick wall soaks up the heat from the sun. Thus making a microclimate for my brugmansias. They have come back two years in a row. The whole time I thought that I dreamed up the idea about double potting. Lol ! What makes it so odd is the pots are above the soil. We are in zone 7a.? Just luck I guess ? But it worked !