Bananas are unique tropical plants that produce large bunches of fruit over and over again. Banana bunches develop virtually overnight, to grow and ripen into sweet fruit before the branch they grow from dies down. Bananas have specific, very unique growth habits that depend more on warmth and water than on season. The care of outdoor banana plants in the winter will vary depending on your climate.
Bananas grow from rhizomes, or corms, in warm, moist and quick-draining sites. The corms put up shoots that grow 15 to 30 feet in height in nine to 10 months, bear bunches of bananas and then die back. New shoots take their place and go through the same process.
Ideal banana-growing regions hare hot and humid, maintain temperatures of 75 to 85 degrees F, and never drop to temperatures under 30 degrees F. Some native banana countries are Brazil, Thailand, Costa Rica, Ecuador and the Philippines.
Bananas grow and fruit successfully in the summer, when they get the humidity, warmth and extreme moisture they need. In the right areas, they may continue this growth year round, but will invariably stop growing at temperatures under 57 degrees F.
After a banana shoot has borne its fruit and died back, a new shoot begins to grow. If a banana plant is grown in an area that remains relatively warm all year, winter will have no effect on this process. In colder climates that get true winters, bananas grow dormant during winter to shoot up again when the ground thaws.
In areas where the weather stays warm, winter banana care should look the same as summer care, with up to 5 inches of water a week and plenty of sun. Bananas require at least 10 frost-free months to set fruit, according to the California Rare Fruit Growers. If you climate receives only a few cold snaps in the winter, it is possible to wrap the banana's trunk with a blanket, or cover it entirely if small, for short periods to maintain its productivity, advises CRFG.
Extended periods of cold weather and frost kills off banana foliage. The corm will survive in the ground down to 28 degrees F, so in colder areas the plant should still receive 2 inches of water a week in order to live and resprout in spring.