I bought a blue potato bush in early spring, It has been through several weather patterns and survived. To keep it like a tree, you have to keep it trimmed and keep the sucklings cut away at the base and else where. I aclamated mine by putting a bag on it before the first frost, this worked for my hybiscuis, until they acloamated to the region. I do it this way with all my plants. By keeping with the size of the bushy part, of the bush to make it look like a tree, keep it in proxcemity of the size that the tree will grow, as much as 4 to 6-8 ft high. Good Luck!