I live in Vermont, and have overwintered my nanners inside easily. I have several different species of ornamental bananas in huge pots on my deck, and up until this year, on the really big ones I'd cut off all leaves , leaving the center one, and brought them inside under T5 lights. They all did fine. Some were small, around 3ft, and one I had was 8ft. I just watered lightly all winter, kept the heater at around 65 or so, and put them all back on the deck in the spring.
Use safer soap for any mite problem. Hope that helps.
