First of all, did you know that bananas aren’t grown on trees? Yep, banana plants are actually perennial herbs grown from a large rhizome (a stem that sends out roots and shoots from its nodes), much like ginger, heliconias and bird-of-paradise flowers. What looks like a trunk is actually a pseudostem, formed by leaves layered around each other. New leaves begin growing below the ground, pushing through the middle of the plant and emerging at the crown. New suckers grow from the rhizome, also called a corm. These can be can be removed and planted elsewhere or left to replace the mother plant after fruiting.
Banana plants can grow over five metres tall but home and garden varieties usually grow around two to four metres in height.
There are two main varieties of bananas grown in Australia – Cavendish and ladyfinger. Cavendish bananas account for over 90 percent of Australian production and includes varieties such as Hybrids, Williams, Mons or Dwarf Cavendish. The lady finger banana is popular in certain regions such as Brisbane.
Banana plants thrive in tropical or subtropical climates, however they can handle cooler temperature if cared for correctly. Growth will stop when temperatures drop below 15˚C but will begin again once it warms up.
Choose a north-east to northerly aspect when growing a banana plant.
“When planting a banana plant, find a warm, frost free and wind protected space, that preferably receives at least six hours of sunshine per day,” Yates Horticulture Consultant Angie Thomas says.
If you’re growing a banana tree in a cooler climate, plant it in a sheltered location near a northerly facing wall.
Banana plants like rich, well-drained soil with reliable moisture. They can tolerate all but sandy soil.
The right time to plant is in spring and summer. Prepare your soil in advance by incorporating plenty of compost or manure and irrigate thoroughly a few days prior to planting. If you’re growing a few banana plants, place them around four metres apart. When planting, create a raised mound around the banana to improve drainage around the roots.
“It’s important to keep the soil consistently moist so it’s helpful to apply plenty of mulch,” Angie says.
Ensure soil is moist but not soaked. Check the topsoil before watering – if the top inch is dry, slowly and deeply water the plant. On average you can expect to do this every couple of days during the warmer months.
“Banana plants are very nutrient hungry and require a potassium enriched plant food,” Angie says. “Apply the plant food around the root zone every eight weeks from spring to early autumn and you’ll promote healthy leaf growth and encourage lots of fruit.”
A banana plant takes approximately nine months to mature and produce fruit however it is important to manage the process. Each cluster of bananas is called a "hand" and each individual banana is called a "finger". The entire stem containing several hands (and many fingers) is called a bunch.
“I recommend covering the entire fruiting stem of bananas with a large open ended bag once the fruit moves from being downward to upward facing,” Angie says. “This will help deter flying foxes, possums and birds from eating the bananas.”
You may have to prop your plant or bunch as the fruit grows heavier to prevent it falling over.
It’s also worth spreading out the harvest season so you aren’t left with bunches of ripe bananas at one time.
“You can harvest individual hands of bananas before they are ripe and allow them to ripen further indoors,” Angie says.
If you’re letting your bananas ripen on the tree, they will be ready to be picked when the little flowers on the end are dry and rub off easily.
“Once a banana plant has fruited it will die, however there should be multiple suckers to take its place,” Angie says. “Remove all apart from two or three of the strongest suckers.”
If bananas are left to produce too many suckers it will reduce the yield of the plant as they can sap energy from the main stem. Excess suckers can be re-planted in pots or in your garden. It’s also important to remove any dead or damaged foliage to reduce risk of fungal infection. Use this foliage as compost.
There are a number of pest problems and diseases that can affect banana plants and biosecurity is a huge issue for the Australian banana industry. Nematodes, weevils, and thrips are the most common pests while anthracnose, rhizome soft rot, banana leaf rust, leaf speckle and crown rot are common diseases. Serious diseases luke bunchy top and panama disease have been known to wipe our entire farms and are closely monitored by authorities.
“If you already have a banana plant growing in your yard, as they mature they will start to develop suckers that can be gently dug up and removed from the parent plant when the stems are around five centimetres thick,” Angie says. “These small plants can then be planted in a different spot in the garden.”