Musa basjoo can be planted outside in areas that go down below the freezing point of water. I grow them in S. Pennsylvania where winters go below zero F (-17C). The plant of course doesn't live, but the corms below the soil come up the next year. Protect them from mice. I grow them in well mulched areas with plenty of water. The side shoot like the OP shows can be buried lightly and it will start to grow roots. When the roots are evident, slice with a sharp knife and plant. Like others have pointed out, it is tough to grow these in a pot, but I don't want to discourage you. Surely people grow them potted to full size all the time.
