No greenhouse here either. Regardless we don't get enough light here over the winter anyway, the plants start looking bad inside no matter what you do. From my experience either leave them out or dig and store.
I have left 1ft tall Basjoo out over the winter with some good mulch cover and it came back the next year no problem. It did freeze to the ground though but sent up many new shoots (pups).
As long as your location isn't too wet then I believe that these plants do very well here outside with minimal protection.
My backyard (where I grow most of my bananas) gets very
wet in the winter. I don't risk leaving the plants back there and simply dig them up and store them bareroot in the garage over the winter. Leaves are trimmed off and no light or water. They all come back fine.
Many people think I'm nuts digging these big plants out each fall but they really come out quite easily for me. Sink the shovel in around the base and the things pop right out. Don't worry about the roots. I use a dolly to wheel them into the garage to save my back
Talk to you soon.