Grown best under hot conditions, a banana tree plant will die if exposed to temperatures lower than 20 degrees F. Therefore, potting is a necessity for banana tree growers in many parts of the U.S. Care is … Cold hardy banana trees … Tropical plants that grow in U.S. Department of Agriculture plant hardiness zones 8 through 11, bananas typically produce their flowers about 10 to 15 months after first emerging from the ground -- though it can take longer if you don't properly care for the plants. Banana plants (Musa) are tender herbaceous tropicals that are similar to weeds when it comes to durability and … How to Care for a Banana Plant in Winter Where it Gets Down to Freezing. How to Plant a Cold Hardy Banana Tree. When you purchase a cold hardy banana tree, you will be given a rhizome—a mass of roots with a starter plant, also known as a sucker, growing out of it. Keeping Your Banana Plant Alive. Perhaps the most obvious way to successfully overwinter a banana tree is to grow … Heavy feeders, banana trees can use 1 1/2 to 2 pounds of 8:10:8 NPK fertilizer monthly for each mature plant, with fertilizer spread 4 to 8 feet from the main stem of the plant. Here, we’ll offer three ways you can protect and preserve your banana plant over the winter months: Container Growing.