Banana plants “walk”

Watched an episode of QI where Sean Lock mentions that Banana plants “walk” (about 2:14 in the clip below). Steven Fry confirms it a little later, according to a “little voice in his head”.

(aside: I’m beginning to think it was scripted, because I found the transcript of an interview he gave for the Science Show where he says something about reading about Malayan dendrology and walking banana plants, so Steven must have known about the moving plants–but perhaps they thought people would believe Sean more)

It’s been haunting me ever since, because I simply cannot imagine how a plant can walk. There’s the issue of roots which make walking tautologically impossible, aren’t they?

So of course being the internet-savvy-type that I am, I queried Wikipedia, and got this:

… the individual stools or planting sites may move slightly from their original positions as lateral rhizome formation dictates. Latin Americans sometimes comment that the plants are “walking” over time.

Aha! I proudly thought – so banana trees DO walk! I MUST tell absolutely everyone I know!

I’m not sure why the question came back to haunt me today, but it did, and I puzzled over the long cab ride home why no one had ever taken a capture of a banana tree walking. Surely a horizontally moving plant would be YouTube fodder or at least of some interest to the Discovery Channel?

So I did a bit more research and now I’m ready to kick myself in the ass, because I’d actually been given all the information I needed to connect the dots, but didn’t. There doesn’t seem to be a ready internet answer to this, so in apology to the people I may have given erroneous information to, here’s an attempt at a reconciliation of the facts.

My basic assumption in thinking that “banana trees can walk” was entirely false – the fact that bananas are trees at all. They aren’t. Bananas are herbs. What that means is that the thing you see sticking out of the ground with the leaves and fruit (the pseudostem) only comprises a part of the banana tree. The actual stem of the banana tree (the corm) is underground (think of ginger).

Banana plant

The pseudostem “matures” in 6 – 8 months, producing fruit and then dying. Usually, another smaller pseudostem will have simultaneously started growing at the same base of the original pseudostem, which will then take over the job of photosynthesis and any other pseudostem roles and responsibilities. The new pseudostem will be, of course, slightly displaced from the position of the old one (see image). Because a banana plant can be cultivated for 25 years and the pseudostems have a relatively short lifespan, as pseudostems die and get replaced it can look as though the plant has “walked” whereas in fact it is the change in position of pseudostems as they replace each other. The only thing that has really “walked” is the position at which the banana corm grows its pseudostem.

In fact I should know this from experience, because I’ve tried to cut down a banana plant and remove its roots (as I thought then) before, and do remember thinking to myself that they extended a bloody long distance and were ridiculously thick. I guess being in a jungle sweating it out with a parang and spade don’t incline you towards pondering the oddness of Nature.

So there you have it. Banana plants don’t walk, not in the slightest. The illusion that they “walk” is due to the withering and resprouting of pseudostems from the underground stem. I’ve learnt something new today (thanks to QI) and I hope you have too. Now go forth, and spread your newly-found wisdom!

But do remember to make use of the air quotes.

Leave a Reply

Your email address will not be published. Required fields are marked *