I have several begonias to dig up and bring in for the winter. Last year I saved the tubers and replanted in the spring. I had pretty good luck doing so. I have a few plants that I just love and would like make new plants from them. Can I bring the begonias in and keep growing them and propagate via stem cuttings? Or should I let the tuber go dormant for a while and then start it up again. How long/short can the dormancy period be?