You can also grow Japanese banana as a potted plant, bringing it indoors from the patio when the weather turns cold. No other banana species offer this kind of versatility, but if you are expecting harvestable fruit, you will be disappointed, as this is not species that produces edible bananas. It can take a full 12 to 24 months for the plant to produce bananas, which won’t happen in climates where it dies back each winter. And even in warm climates, the bananas are just small fruits filled with black seeds and a little white pulp. As a garden plant or potted plant, however, Japanese banana is excellent for lending an exotic tropical feel. It is ideal, for example, to grow alongside swimming pools, or on sun porches. When planted in the garden, Japanese banana is normally planted in the spring. It is a fast-growing plant that can achieve its full mature height in a single growing season. Don’t be alarmed if it does back to the ground in winter, as it will quickly shoot up again the following spring. Another option is to plant it in a large container and bring it indoors for the winter months to continue growing in a bright location. It needs quite a large space, however. Watering and feeding can be somewhat reduced during this time. If you don’t have a space sufficiently large enough to grow them indoors, another option is to cut off the foliage, then dig out the root ball, trim the roots and wrap them in plastic, and store them in a cool dark place until spring planting time. This fast-growing plant will die back each winter in colder climates, but even where it is evergreen or grown as a houseplant, it will renew itself and die back after each fruiting season. The pseudostem dies away, but the plant continues growing by sending up new shoots from “pup” offshoots.
Light
The Japanese banana should be planted in a location that receives at least 6 hours of sun during the day, though they will appreciate some shade during the hottest part of the day. When grown indoors, give it the sunniest location you can find.
Soil
In the outdoor garden, plant Japanese banana in rich, well-drained soil. The soil needs to be consistently moist. When growing Japanese banana as a potted plant, use a good-quality, well-draining potting mix.
Water
Keep these plants constantly moist; these are subtropical plants that do not react well to drought. They should not, however, be allowed to soak in water; good-draining soil is a must. Potted plants brought indoors can be watered less frequently during the winter.
Temperature and Humidity
These plants are native to subtropical regions, but will survive as perennial plants down to minus 10 degrees Fahrenheit if the root zone is thickly mulched. At about 40 degrees, growth stops, and at 32 degrees, the foliage will die back. Japanese banana prefers relatively humid conditions but will tolerate dry indoor air, as is common during the winter months. It does not demand misting, as do some tropical plants.
Fertilizer
These plants should also be fed every two weeks throughout the growing season using a water-soluble fertilizer. When bringing potted plants indoors to grow through the winter, reduce fertilization to a light feeding once a month.
Related Banana Varieties
There are no additional cultivated varieties of Musa bajoo; the species plant is the only one cultivated for the garden. But there are a number of related banana species that are often grown as garden plants or large houseplants:
Musa × paradisiaca is the species most commonly grown for edible bananas. Hardy only in zones 10 and 11, it grows to 25 feet and requires a lot of space if grown as a houseplant. There are several cultivars available, including ‘Orinoco’. Musa acuminata is a tropical banana that is sometimes grown as a large houseplant. It is hardy outdoors only in zones 10 and 11. It is a large plant, growing to 20 feet. Popular cultivars include ‘Siam Ruby’, with reddish leaves flecked with chartreuse; and ‘Zebrina’, with blue-green leaves that are striped with red. Musa ornata (flowering banana) is hardy in zones 9 to 11. It is a smaller plant, topping out at 9 feet, making it a good houseplant. It is known for attractive orange-yellow with purple-pink bracts.
Pruning
Remove damaged or diseased leaves when they appear. In winter die-back zones (zones 5 to 8), cut back the pseudostems to about 2 feet after frost has killed the foliage.
Propagating Japanese Banana
The plant will send out rhizomes called banana pups. After the roots form on the pups, you can remove a few from time to time to produce new plants. If you remove a lot at the same time, the plant may tip over. A Japanese banana that fruits after one to two years will die back, and this is a good time to choose a strong pup to develop as the main tree to replace the old pseudostem.
Potting and Repotting Japanese Banana
Japanese banana will grow in almost any pot, but it is best suited for a large container that can sit on the floor with plenty of space around it. Ideally, use a large 12- to 24-inch-wide pot. A good-quality potting mix based on peat moss will have the slightly acidic pH these plants crave. The pseudostems will die back every one to two years so repotting is usually not necessary, but when the plant dies back after fruiting, this can be a good time to choose a single “pup” offshoot to repot.
Overwintering
For plants grown as perennials in cold-weather zones, cut back the pseudostems to about 2 feet, wrap them in burlap or bubble wrap, then apply a thick mulch over the root zone. For potted plants grown on the patio, bring the plants indoors before the first frost and give them the sunniest location you can find. Keep temperatures at 65 degrees Fahrenheit or higher, if possible. Reduce watering and feeding slightly, but don’t let the soil dry out completely. If you don’t have the space to grow them indoors, another alternative is to dig out the plant, trim the roots, wrap them in plastic, and store them in a cool, dry location for the winter. They can be replanted in the spring.
Common Pests/Diseases
Several pests can become especially bothersome on Japanese bananas grown as houseplants. These include aphids, mealybugs, scales, and spider mites. You can try treating the plant with an organic method like insecticidal soap, but control can be difficult and you may ultimately need to throw the tree out if the infestation is serious enough.