Bananas are tropical plants that belong to the Musaceae (plantain and banana) family. The cultivated varieties of bananas available today originate from ancestral species native to the Malaysian peninsula, New Guinea and South-East Asia.
Even though banana plants are mistakenly referred to as trees, they’re actually herbaceous plants (plants that have non-woody stems) because their sturdy, succulent stem is not a true stem, but a pseudostem which is comprised of concentric layers of leaf-petiole sheaths, or put more simply, a cylinder of rolled up leaf bases.
Bananas are tall and tree-like in growth habit, with dwarf varieties growing 1.5-2.5m (5-6′) tall, and the tallest reaching reaching a height of 6.0-7.5m (20-25′), making them the world’s largest herbaceous perennial plants!
Can Bananas Be Grown in Temperate Climates?
There are many banana varieties that are tolerant of colder temperatures, and can be grown in temperate climates. The following cold-tolerant banana varieties are available in Australia:
- Ducasse, grows to 3-4m tall
- Dwarf Cavendish, grows to 1.5-2.5m tall
- Dwarf Red Dacca, grows to 2.0m tall
- Goldfinger, grows to 3-4m tall
- Ladyfinger, grows to 3-4m tall
- Pisang Ceylon, grows to 3-4m tall
- Rajapuri, grows to 2.0-2.5m tall
- Valery, grows to 3-4m tall
Here in Melbourne, Australia, which has a temperate climate, and increasingly shorter summers, I’m successfully growing Dwarf Cavendish, Goldfinger and Rajapuri banana varieties, and colleagues of mine have also grown Ladyfinger bananas and produced good harvests of fruit.
Banana Flowering and Fruiting
Bananas may take 2 to 3 years before they produce their first fruit. If winters are far too cold, they will usually skip fruit production in spring-summer, and fruit in the next year instead.
When bananas are ready to fruit, a large, long, tapering, oval-shaped reddish-purple flower bud will be produced. The bracts of the flower will roll back and split to expose a line of slim, nectar-rich, tubular, toothed, white flowers, which will be pollinated to form a hand of bananas.
Once all hands of viable fruit are exposed, the bracts will continue rolling back and splitting for a few weeks, leaving a long, thin bare stalk between the hands of bananas above, and the reddish-purple male flower bud below.
There is no benefit to leaving the male bud at the end of the flowering stalk hanging below the last hand of bananas. If it’s removed immediately after the lowest row of female flowers above have set fruit, this will speed up fruit development. Cut off the male bud several centimetres below the last hand of fruit.
Why Bananas Don’t Ripen On the Tree in Temperate Climates
In subtropical and tropical climates, bananas can ripen naturally on the tree, though this may not necessarily be the ideal approach as we’ll see shortly.
The problem in temperate climates is that there may be insufficient warmth or the summer season may be too short, leaving the bananas green at the beginning of winter. If the fruit is left on the tree through winter, it will be damaged by the cold and begin to rot fairly soon afterwards.
What Is the Best Time to Harvest Bananas?
Bananas don’t always attain their best eating quality when left to ripen on the tree. Generally, bananas are harvested before they begin to turn yellow, when the fruit on the upper hands begin changing to a light green colour, when individual bananas become plump and more rounded, and lose their ridges. This is usually when they reach full size or are close to it, and the black withered remains of the flowers (styles) at the ends of the bananas become dry, crumbly, and easily rubbed off the tips. When these changes appear in the fruit, it is an indication that the fruit is fully developed, is around 75% mature, and will ripen to good eating quality.
Even though it’s possible to just harvest a hand of bananas as required, normally the whole banana bunch is harvested by cutting the stalk 15-20cm (6-9″) above the bunch to serve as a handle for carrying it. Traditionally bananas are harvested with a curved knife to make the task easier.
The harvested banana bunch is then taken indoors, hung in a cool, shaded place and allowed to ripen fully. This should take a few days if the fruit is properly developed and ready for ripening. Once the oldest hand at the top of the bunch starts ripening, the entire bunch will ripen a couple of days later.
Bananas can be ripened very quickly and effectively by placing the whole banana bunch into a paper bag, such as a brown paper food delivery bag, placing an apple or two in there, and folding the bag closed.
As apples ripen further, they release ethylene gas, the same compound that’s used commercially to ripen immature fruit, and this will start the bananas ripening.
In my experience, I harvest the banana bunches in the middle of the first winter month (June in Melbourne, Australia – southern hemisphere), and leave the bananas in their bag with the apples for around 5 days. The oldest hands will ripen first, then the rest rest will follow soon after. I remove the individual ripe bananas from the bunch as soon as they look evenly yellow, then inspect the bag each day to see if any more bananas are ready. If they’re left in the bag too long they over-ripen very quickly!
After Harvest Tasks
A banana stalk (pseudostem) produces fruit only once. After the fruit has been harvested, the stalk is cut off at the base, level with the soil, chopped into small pieces and either incorporated (dug) into the soil or composted.
Bananas have a rhizomatous root system which puts up new stalks each year, and these new shoots are used to replace the stalks that have fruited and been cut down.
For good fruit production, and efficient use of space, it’s best to limit a banana plant to three or four stalks that are of different ages. With this system, the oldest and tallest banana plant is the one that’s flowering or fruiting. The second banana plant should be 1/2 to 1/3 the size of the first. There should also be one or two young plants that are up to 90cm (3′) tall which will serve as replacements of the older plants.
- Morton, J. 1987. Banana. p. 29–46. In: Fruits of warm climates. Julia F. Morton, Miami, FL. <https://www.hort.purdue.edu/newcrop/morton/banana.html>
- Texas Cooperative Extension, Home Fruit Production–Banana by Julian W. Sauls https://aggie-horticulture.tamu.edu/extension/homefruit/banana/banana.html
- University of Florida Extension, Garden Solutions, Bananas <https://gardeningsolutions.ifas.ufl.edu/plants/edibles/fruits/bananas.html>
- University of Florida Extension, Banana Growing in the Florida Home Landscape, Publication #HS10, Date: 07/01/2020 by Jonathan H. Crane and Carlos F. Balerdi https://edis.ifas.ufl.edu/publication/mg040
- PlantVillage, Banana, https://plantvillage.psu.edu/topics/banana/infos