Jennifer Schultz Nelson
Extension Educator, Horticulture
I love using tropical plants in my garden, but personally I hate having to bring them in for the winter. At least most of my tropicals are in pots, so there is no digging involved. If a plant has to be dug out of my garden in the fall, it has to be a very special plant.
I was thrilled when a Master Gardener drew my attention to the hardy banana a couple of years ago. My heart skipped a beat when I found out it was winter hardy to Zone 4! No digging or dragging pots indoors! I've wanted one ever since.
Besides adding a tropical look to gardens, the hardy banana, Musa basjoo, is a fascinating plant. It, along with other species in the genus Musa are the world's largest herbaceous plants, mostly originating from tropical climates. Many species of Musa routinely grow more than twenty feet tall! The hardy banana grows to be anywhere from 12 to 18 feet tall, so it will probably attract some attention if planted in your garden.
While sometimes we talk about banana 'trees', in fact all parts of the plant are herbaceous–no parts are woody. What many of us mistake for the 'trunk' of the banana tree is in fact tightly wrapped leaves. Botanically speaking this is a pseudostem, meaning 'false' stem. Unlike a lot of plants, the growing point for a banana plant is not near the outside of the plant. It is deep within the pseudostem near the base, much like how German irises and canna lilies grow.
Banana leaves have evolved an interesting way to save themselves from certain death during tropical storms. Keep in mind that a banana plant may have relatively few leaves, but they are huge. In some species they may be eleven feet long! The veins on each leaf are perpendicular to a very large central midrib. In very windy conditions, the leaf will shred into strips along each side of the midrib. This may look ragged, but despite appearances still functions normally. If the leaf did not shred in the wind like this, it's likely that since banana leaves are so large they would be snapped off by high winds.
Each pseudostem on a banana plant has a limited lifespan. It only lives as long as it takes it to flower and produce fruit. For many species, this can take the better part of a year. In our central Illinois climate it is unlikely that the hardy banana will grow long enough to produce fruit. If it does, unfortunately it is not edible.
Why would anyone grow a banana plant that produces inedible fruit? The answer lies in the other common name for Musa basjoo–Japanese fiber banana. Musa basjoo is actually from the Ryukyu Islands of Japan, and historic records indicate the Japanese have cultivated the banana for fiber since the 13th century.
The fibers are extracted from shoots by boiling the shoots in lye. Then the fibers are spun into yarn and used for garments. The fibers extracted from a shoot will vary in how coarse or soft they are. Those near the outside tend to be coarser, while those in the center are much softer. Other cultures also use banana fibers, but the extraction method differs. The end result is very similar. The softest fibers have been compared to silk in how they feel and look when used in textiles. Banana fiber can also be used to make paper.
I guess you could say that everything old is new again. I enjoy knitting and lately I've seen many "new" fibers advertised, including "banana yarn". A fiber used since at least the 13th century doesn't exactly sound "new" to me!
I would love to plant a hardy banana in my garden. My husband on the other hand, is not thrilled about the hardy banana and has made what I'll admit is a pretty good argument as to why we shouldn't grow one.
While it is hardy to Zone 4, in our climate it dies back to the ground and needs heavy mulching to survive the winter months. This is a concern because our home is in an area very prone to small rodents wreaking havoc in our landscape during the winter months. The large pile of mulch needed by a hardy banana would be like an engraved invitation beckoning mice and voles from far and wide to spend the winter with the Nelsons.
I have read some accounts of gardeners overwintering hardy banana without mulch. This may be the only way I'll ever get a hardy banana in my yard. But I don't know if I trust Illinois weather enough to try it. I'll admit, I have snuck a plant or two into my garden under my husband's radar. I don't think that's possible with the hardy banana, considering its size. There's no good way to hide a 12 to 18 foot plant in the garden!