Growing Bananas in Hobart

In Tasmania banana plants are sometimes for sale in nurseries, but people who try to grow them in our climate never seem to have much success. So I was a bit skeptical when Karen D, after recently joining the Food Garden Group, told me that she grows her own bananas. In this blog post Karen explains how she does it.

I wanted a plant for my north-facing sunroom that would tolerate hot dry conditions through summer and cope with cool winters, so in mid 2008, I bought a dwarf lady finger banana called Dwarf Cavendish, as an experiment. The label said 'Cool Bananas - fruits under cool conditions'.

I soon realised there was a lot to learn.  My banana plant became a hobby.

Plant Maintenance
I planted my 'Cool Banana' in a 50cm pot and it is still in that pot today.

It needs to be well watered throughout warmer months and periodically through winter for the soil to remain moist. The roots mustn’t remain wet as they can rot.  I would water from the top and let the saucer half fill only re-watering once this was absorbed.

In summer I would have an indoor fountain going to encourage moist air to form to achieve a tropical growing environment.  In summer I also usually have a bottle with water upside down into the soil, so its content gradually drains into the soil.

My fertilizing regime was adhoc, as I was learning as it grew.  Twice during summer it would get a feed of Seasol or Nitrisol, although recommendations are for every 6 weeks (whoops!).  Recently I have for the first time applied a 9-month slow release fertiliser on new plants.

It was never fed during winter as its growth ceased.

The plant seemed happy, became taller and new leaves became larger.  It grows from the centre where it produces new leaves.  Research (see [1] ) told me that it was supposed to shed 44 leaves before it would flower (although who was counting), so I knew I would have to be patient.  Over time outer leaves died (see photo below) and these, together with their old dried stems were cut off.

During winter the plant went dormant with no new growth.  I was particularly careful to keep it well away from cold windows to keep the foliage safe from frost at night.

Taking care of new shoots
Every summer the plant would form new shoots ('volunteers') at the base of the mother plant (see photo below).

I always carefully removed them and put them in pots, usually to give them away.

A banana stem will only set one flower ever.  It is then spent and dies off.  If you want a succession of bananas, treasure your volunteers.  Pot them up, look after them, and you may have a succession of bananas over the years.

This is what I now do with volunteers:

• I wait until it is 15-20 cms high
• I then take the whole plant out of its pot.
• I then remove the volunteer carefully so as not to cut its independent roots
• I plant it in a 20cm pot
• I replant the mother plant in the same pot it was in before

Pest Management
The only pest I encountered in the following years was that it would sometimes get a small woolly-like mould (size of a pin head - see photo below).

I still don’t know what exactly that is.  I treat this by putting milk on a damp sponge and wiping all leaves clean. This eradicates it and the plant continues to grow.

Flowering
In January 2013, that is 4 ½ years after I had bought it, my banana plant began to flower.  It is called 'banana inflorescence'.  It may have been after its 44th leaf had been shed.

It is recommended that you fertilise a lot more during flowering/fruiting, so I began to fertilise the plant every two weeks with a weak Seasol solution.

 

On 25 January 2013 its flower looked like this:

Whereas you would expect fruit to develop as a result of pollination, this is not the case with Bananas. Instead, the ovaries contained in the first female flowers develop without pollination into clusters of fruits, called hands (for more info see here).

A banana plant will only set one flower, so I realised how important it was that this flower succeeded. The plant was now six feet high, including pot.  It was not going to be any taller.  Once a plant finishes fruiting, stem and leaves are cut up and composted, and that is the end, if you did not pot up any new shoots.

When the flower appeared there was a 20cm volunteer at its base.  My concern was 'should I remove it or not?'.  If I would attempt to remove it, I would need to remove the whole plant from the pot, make sure not damage the flower in the process, and make sure not to loosen the soil around its roots. Would I stress the plant by removing the volunteer?  Knowing that the volunteer was competing for nutrients with the flower and fruit, I chose not to disturb the plant, but fertilise the plant more often (fortnightly).

Fruit development
On 31 January 2013 little bananas began to appear:

Things progressed quickly from here.  The photo below was taken one day later:

I didn’t know if staking would be required while the flower and fruit developed.  I monitored this and eventually gave it a small spiral stake as the plant began to lean.

As each petal (called a 'bract') lifts, there are five little bananas under it.  I allowed the five bananas on each 'hand' to fill out until they had a round shape.

This is how things looked on 6 February 2013:

After five petals had lifted (in other words 'I had five hands'), I decided to cut off the end of the flower, so the plant could direct its energy into the fruit and all bananas would all grow and fill out.

I then cut a hand at the time and placed them in a brown paper bag to continue ripening.

This photo was taken on 16 June 2013:

These Dwarf Cavendish bananas taste like 'normal bananas', no sweeter than any bought in the shops, but I watched them grow, and that was exciting!

Where from here?
I currently have six plants at various stages of growth.  Over the lifetime of my original plant I gave away at least eight other small banana plants.
Some of them are now in my hothouse, as I don't have space for them in my sunroom.  My hothouse is well insulated.  The glass was replaced with 'Makrolon'.  I will need to monitor how they cope.

I am aiming and hoping for a staggered harvest from here on.
I believe my current bananas are due to flower in January 2018.

If you would want to grow a banana plant outside in Southern Tasmania

Locate it in the warmest most sheltered spot you have.  It would need to be kept sheltered from the wind at all times, as the leaves may get shredded.  The plant would require a support stake.

Here are a few useful websites for further reading
[1] www.crfg.org/pubs/ff/banana.html
Info from the company the original banana plant came from: http://humphris.com.au/blog/portfolio/banana-dwarf-cavendish/