If you are growing your banana in pots you can easily grow them indoors over the winter months. Be sure to give them as much light as is possible inside your home and keep them a little on the dry side. If you do not have room for them inside of your house but you have a cool garage or shed, you can easily store them inside of it over the winter.
Winterizing using the Chicken Wire Method
After the first good frost when the leaves turn brown , cut your banana tree down to 2-3 feet (60-90 cm). Dispose of the leaves on the compost pile. Place 4 stakes about 3 ft apart in a square pattern, leaving the banana stump in the center. Place 1 to 2″ chicken wire or fencing wire around the posts forming a 3ft x 3ft square basket. Place a small plastic bag over the stump of the banana to prevent water getting in. The chicken wire should be about 3 to 4 ft high. Fill this basket now with leaves until full. The banana tree is protected from the hard winter frosts but is still able to breathe properly on those nice sunny winter days.
Early March is a great time to remove the leaves basket. .
Winterizing using the Water Pipe Insulation Method
The largest banana trunks can be wrapped with water pipe insulation that can be found at most hardware stores. Be sure to fold the top over to make sure that no water gets inside the insulation. The leaves of the banana plant should be stripped off in the fall and placed above the root ball and the base of each banana trunk. You can also use any other organic materials except Walnut leaves. Mulch as deep as possible. In the spring remove the plastic and mulch and watch it grow back very quickly.