A perennial plant that grows from a swollen, fleshy rhizome root, the Japanese fiber banana (Musa basjoo) is regarded as the most cold-hardy banana for gardens. Not producing edible bananas but growing as tall as 10 to 18 feet, this native of Japan's Ryukyu Islands is killed back to the ground by fall frosts, but the roots survive in the ground if mulched from the cold. Grow this tough banana species in USDA hardiness zones 4 and warmer. In zones 4 and 5, winter mulch is necessary.
Wait until all danger of spring frost has passed in your region. Consider waiting two weeks after this date to allow the soil to warm well above 60 degrees F, although it is not necessary.
Cultivate the spot where you wish to plant the banana rhizomes with a garden shovel, at least 3 feet by 3 feet square, according to the University of Florida Extension Service. Dig the soil, overturning it and breaking it up to a depth of 10 to 12 inches. Smash any soil clumps to create a crumbly, soft soil.
Add compost or well-rotted manure or other fine-textured organic matter to the planting area, and incorporate it with the shovel. Sandy and clay soils in particular benefit from the addition of a lot of organic matter to improve water drainage and overall crumbly soil texture.
Examine the banana rhizomes, noting their general size and where the growing tip is located.
Dig a planting hole large enough to hold the rhizome's size but shallow enough so that the growing tip of the rhizome sticks only 1/2 inch out of the soil once planted.
Place the rhizome in the planting hole, steadying it so that the growing tip is at the proper height, just above the top edge of the hole. Pull soil into the hole with your hands, burying the rhizome. Remember that the growing tip must remain 1/2 inch above the soil line once the rhizome is planted.
Create a watering basin around the planted banana by moving excess soil into a circular berm about 3 to 4 inches high.
Water the newly planted banana with a sprinkling can or garden hose until the soil is moistened to a depth of 10 to 12 inches. Depending on how quickly your soil drains, consider filling the watering basin two or three times to remove air pockets in the soil and compact the soil around the rhizome.
Place a layer of compost or other organic mulch atop the planting area to retard weeds and retain soil moisture. The layer should be 3 to 4 inches deep. Keep the mulch 6 inches away from the growing tip of the banana rhizome. Allow the sun to heat the soil around the rhizome and hasten the sprouting of the plant.
Fertilize the banana with a well-balanced liquid fertilizer product in conjunction with a watering only after the growing tip sprouts and it at least 2 inches tall. If the weather is chilly, with temperatures below 70 degrees F, hold off on fertilizing until more reliably warm weather consistently returns.