The foliage is not evergreen, but the roots are considered hardy to -10C. The better you manage to protect the stem and roots, the better your plant will recover in spring. Protect the roots with a thick layer of straw or mulch around the base of the plant. Cut the old leaves off. The stem may be protected by wrapping with hay and then reed matting. Christmas lighting may even be integrated into this insulation to give that little bit of extra warmth on really cold nights. Be sparing with water during the cool months. If you discover that the pseudostem has not survived the winter don’t worry; the plant will rapidly grow to its full size again in spring if the root has survived.
Musa basjoo is a hungry, thirsty plant. So your home-grown jungle needs a little work! Treat it to organic or fluid fertiliser every second week and water abundantly. It may be a chore but your fully grown banana plant will have been worth it! The leaves of this plant are exotic to put it mildly. But there is a downsize; they are vulnerable to wind damage and the plant can look a little ragged towards the end of the season. Of course, you can work to prevent this damage but erecting screens or even planting other Musa basjoo plants. Some simply accept the ‘ragged look’ for what it is.