If there is one garden style that has really taken off during the last couple of years it’s the trend for tropical style gardens. With the increased spending on home gardens during the Covid pandemic there are no doubt a lot of people wondering how to over winter their newly purchased banana plants.
Bananas are in a group of about seventy species in the genus of Musa. They are indigenous to India, SE Asia and Northern Australia. Obviously they are not going to be used to the type of winters that we get in the UK! So how hardy are they?.
Here we are looking at the hardiest type, Musa Basjoo.
As the temperature drops the leaves will stop growing at 12 degrees Centigrade. They will start to get leaf damage at zero degrees centigrade.
Now we come to the stem, the hardiness of which depends greatly on it’s thickness. A young pseudostem will die at a few degrees below freezing but a more mature stem of a thickness of 4-6 inches will tolerate temperatures down to minus 8 degrees Centigrade.
Do not fear the worst however if your stem does die because the plant might well grow back from the rhizome roots, which are hardier. Of course you are going to lose the height in next year’s plant.
So what should you do to protect your banana in the winter? Well, it depends greatly on how big the plant is and your indoor storage accommodation. If the plant is in a pot or relatively small, then the easiest thing to do is to bring the plant in to a frost protected indoors area. The problem is that bananas grow pretty quickly and can easily reach 3 meters in height in three years, so, after a couple of years people find that the plant will no longer fit in their sheltered area! They will, however, survive outside if a few precautions are taken.
If you want your plant to grow from it’s existing stem then the stem will have to be wrapped. The first thing to do though is to cut off the leaves. Do this after the temperature has gone low enough to blacken the edges of the leaves. This triggers the plant to go in to a state of dormancy.
Then wrap the stem in a few layers of horticultural fleece. This will have to be tied to keep it in place. If you live in a fairly mild winter area this might well be enough but for harder areas then you are going to need further protection. Hesian sacking can be wrapped around the fleece. This is quite awkward stuff to get in place and will have to be tied like the fleece. make sure that the ties have a bit of play and are not strangling the stem.
For the really cold areas you are going to need a further layer. The most effective insulator for this is straw. the problem is getting it to cover the stem. One method is to make a chicken wire cage around the stem, held in place by a couple of stakes. This can then be filled with straw.
The problem with any wrapping is that the stem can easily start to rot if it gets wet or has no air circulation for extended periods of time. To help to alleviate this, the stem needs to have a final outer layer that is waterproof. Old washing line covers are ideal. The stem should also only be covered when there is a real risk of very low temperatures.
The roots should be covered with a thick layer of mulch.
So will your new plant ever produce bananas? The answer is probably not and if it does they won’t be edible. Also it’s worth remembering that bananas are monocarpic, that is they die after producing fruit! However if it’s mature enough to produce then it will have made ‘pups’ and you will get a new plant from these.