Banana plants (Musa spp.) grow natively in tropical and subtropical locations where the average temperatures are around 80 degrees Fahrenheit. Most varieties are hardy in U.S. Department of Agriculture zones 7 to 11. They require warm temperatures, full sunlight and plenty of water to grow their large leaves and produce fruit. The edible banana plants do not grow well in locations with freezing temperatures, while the ornamental banana plants are a little more cold tolerant. The amount of damage done to a banana plant depends on the drop in temperature, the length of time exposed to freezing temperatures and the amount of winter protection.
To produce edible fruit, a banana plant needs heat throughout the year without exposure to freezing temperatures. Just a light frost will stop the ripening process, which will continue in the spring, but a hard freeze will permanently stop the process by killing the fruit. Frozen bananas turn black and mushy. Remove the ruined bananas in the spring to make room for new fruit growth.
During the winter, banana plants only develop one leaf each month as a response to the cooler temperatures. Light frosts burn the leaves of most banana plants, but the damaged plant will send out new leaves to replace the leaves. Do not remove the leaves right away since the limp leaves add extra protection to the stem. Cut off the freeze-damaged leaves when new leaves appear.
Banana plants do not contain any woody parts, even in the trunk. The trunk is a bundle of tightly wrapped leaves called a pseudostem. The active growing point in a banana plant is contained deep in the pseudostem near the base of the plant. When exposed to a hard freeze, the pseudostem turns brown and oozy. Do not dig the plant up and discard if this happens. Cut the pseudostem to the ground level and wait for warmer temperatures. Most likely, new shoots will sprout from the roots.
Prolonged freezing temperatures during the winter will kill the roots below the surface of the ground. The ground must freeze solid for this to happen. During this event, all the top portion of the banana plant is killed off. If a small section of roots survives, it will resprout in the spring.
The Japanese fiber banana (Musa basjoo) is the hardiest banana plant cultivated. It is hardy down to USDA zone 4. The plant survives temperatures down to minus 20 degrees Fahrenheit with a thick layer of mulch. In harsh winter zones, cut the tops off the banana plants and pile on a thick layer of mulch to protect the roots. Do not expect any fruit production in these locations since the banana plant regrows from the roots each year.
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