I have a bonsai tree - a ficus, I believe. I have been its caretaker for several years. During this time the tree has survived, but I have never felt it has really flourished. I have many questions about its care, but here is a big one. I live in Zone 5. Should I be leaving my tree outside in the winter or taking it in to live in the house? In the summer, should I put the tree out in full sun or keep in on my north-facing porch? Thanks for your thoughts.