Musa basjoo has been one of my favorite garden plants ever since I first started growing it in my first garden in southwestern Germany. For a lush, tropical look in a temperate garden hardly anything beats these surprisingly hardy, rapidly growing plants. They do need careful siting and quite a bit of winter protection in most places colder than Zone 8 but are otherwise almost care-free. In the milder parts of Germany as well as much of northern France Musa basjoo has become increasingly popular in recent years and it has long been a mainstay of exotic planting schemes in such famous British gardens as Christopher Lloyd's Great Dixter, Alan Gray and Graham Robeson's Old Vicarage, or Heligan.
Musa basjoo in a south-facing border at my parents' previous house in Zone 6a suburban Michigan
Origin: Musa basjoo is native to the Ryukyu Islands in southern Japan.
USDA Hardiness Zone: Leaves are damaged even by light frosts and stems are only somewhat hardier but the rootstock is hardy to Zone 6b according to several sources and at least to Zone 6a according to my own experience.
An old stand of Musa basjoo in the Zone 8a palace gardens in Karlsruhe, Germany
Size: Musa basjoo can reach heights of 15' (ca. 4.5m) and clumps can theoretically reach a similar width but in colder regions the plant's spread is effectively limited by the extent of winter protection one is willing or able to put in place for it.
Flowering Time: Due to winter stem die-back Musa basjoo is unlikely to flower in colder areas. However, in Zone 7b and warmer or if overwintered indoors large specimens can produce huge clusters of yellowish flowers subtended by large greenish-orange bracts at any point during the growing season. These in turn may develop into small, inedible green bananas.
Light Requirements: Musa basjoo needs full sunlight, the more the better.
Musa basjoo resprouting in early May at my parents' previous Michigan home.
Soil Requirements: Due to its rapid growth, Musa basjoo needs fertile soil and plenty of moisture and benefits from a soil enriched with plenty of organic matter as well as frequent top dressings of compost and leaf mulch. However, good drainage is also important since otherwise rootstocks might rot, especially during winter.
Siting in the Garden: Musa basjoo needs a sunny and protected spot in the garden to minimize winter damage and promote lush growth. An ideal place would be a bed or border in front of a south-facing wall, especially in cooler areas. Both in Germany and in southeastern Michigan, I have successfully grown this species in borders backed by the south-facing front of a house. Walls also often provide protection against excessive rain during the cold season, thus reducing the risk of rot. Furthermore, the large leaves of this plant also make it susceptible to wind damage, so if possible it should be planted in a spot where it will be sheltered from strong winds.
Care: Musa basjoo should be planted in spring or very early summer so that the plant has plenty of time to establish itself before it has to survive its first winter. The soil should be amended with plenty of compost if possible, and a good dose of bone and blood meal should also be worked into the soil, and a good cover of leaf mulch or fine-ground wood chips . Once established, the plant needs little care during the summer months apart from regular watering during dry spells. A bi-weekly feeding with water-soluble fertilizer also helps to encourage strong growth but is not absolutely necessary and should be stopped in early fall in cooler areas. Once the first light frost has caused the leaves to begin to wilt in the fall, a cage of chicken wire and burlap or bamboo mats should be built around the clump and filled with dry leaves for winter protection. Pre-fabricated wire compost bins are also excellent for this. I like the mulch to stand at least 2-3' (ca. 0.6-1m) high but the higher you can pile the mulch the better. Overall, the better protected the rootstocks and stems are the more likely it is that significant stumps of the stems survive which in turn allows the plant to regain size more quickly the following season. In spring, the leaf mulch should be removed once temperatures have warmed up and are no longer likely to drop in the freezing range. Care should be taken while removing the mulch covering since the plant will most likely have sprouted already and the young pale shoots are quite fragile. A good amount of bone and blood meal should be lightly worked into the ground around the plant and a new layer of compost and mulch applied at this time so the plant is set for another season of lush growth.
Propagation: Musa basjoo can be propagated quite easily from the large number of suckers or "pups" the plant produces. To do this shoots at the edge of the clump should be selected and carefully separated from the mother plant once they are about a 1' tall. Care should be taken to preserve as much of the rootstock of the young plant as possible. Clumps can also be divided and divisions replanted but since the corms can get very large and extremely heavy this can be quite difficult.
Early fall picture of young specimens of Musa basjoo planted last spring in my family's new Zone 6a southeast Michigan garden
Use in the Garden: Musa basjoo adds a tropical touch to any planting scheme and makes a great, eye-catching backdrop for a sunny perennial bed but also integrates well into a shrub border provided it receives full sunlight. Where the climate allows it can also be stunning as a solitary clump surrounded by lawn or low ground covers.
Palms Won't Grow Here and Other Myths: Warm-Climate Plants for Cooler Areas by David A. Francko, Timber Press, 2003.