Carnivorous plants

Posted: Monday 27 September 2010
by James Alexander-Sinclair

To small boys the fact that [the Venus fly trap] cannot devour live chickens or younger sisters will always be a disappointment.

Pitcher plantsOne of the enormous privileges of writing this blog (apart, of course, from the legendary seven hour Gardeners' World lunches and scuba diving from the Editor's private yacht) is the chance to write about things I know virtually nothing about. This way I find out about new plants and curiosity about the world is a healthy thing.

Today the subject about which I know nothing is carnivorous plants. I had a Venus fly trap when I was a boy and it was a source of great fascination - although sadly not for very long as I soon choked it to death with a fat bluebottle. To small boys the fact that the plant (Dionaea musicipula if you wish to be correct) cannot devour live chickens or younger sisters will always be a disappointment.

Put simply there are four different forms of carnivorous plant: fly traps, pitcher plants (in the genus Sarracenia), butterworts (Pinguicula) and monkey cups (Nepenthes). Examples can be found in most parts of the world, where they have evolved to cope with their surroundings from the acidic bogs of Europe to the Australian desert and the alligator-riddled swamps of the American Deep South.

Here are my interesting facts:

Fly traps were described by no less a fellow than Charles Darwin as one of the most wonderful plants in the world. The cleverest trivial fact I know about them is that they only spring closed if two hairs are touched simultaneously. This stops it using up a lot of energy unnecessarily on very small meals. It eats more than flies*.

A larger group are sarracenias or pitcher plants (there was a particularly striking group of them in Tom Hoblyn's Chelsea garden in 2009). These have slippery sides into which insects fall and are then digested by the fluid at the base of the pitcher. There are large colonies growing in both Ireland and Cumbria. This is a slightly gory video of the demise of a wasp*.

Butterworts appeared in this country by accident as they were brought back by Victorian plant hunters in shipments of more obviously beautiful plants like orchids. They have the best flowers and are very useful in greenhouses where they catch whitefly and other greenhouse pests.

Nepenthes produce very fetching striped cups which dangle from the plant like Sherlock Holmes' pipe. The necks of the cups are brightly coloured and smeared with insect attracting nectar from where it is just a short fall into the digestive fluid that dissolves them within about a week. Some nepenthes have sharp spikes to stop monkeys from robbing the traps as it is an easy food source. They can catch small mammals as well*.

In some places the digestive fluid is used as an eyewash or a laxative. In Thailand there is now a great shortage of nepenthes because people used to cook rice in the pitchers, it gives it a particular flavour. Yum.

So now we both know a bit more. If you want to find out much more useful stuff then try The Carnivorous Plant Society.

* Nature is not always kind: a warning to the squeamish.

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Talkback: Carnivorous plants
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Gardeners' World Web User 28/09/2010 at 12:11

There is one that can catch and digest a rat! Children always find them interesting and not just the boys. I think it is easier for them to understand than plants getting nourishment from roots.

Gardeners' World Web User 28/09/2010 at 19:36

There are a few more groups, some less common than those mentioned in this blog. Sundews, or Drosera have thin leaves in various shapes all of them have sticky tipped tentacles covering either the entire leaf or at the tip. These are excellent corn fly control because as soon as the corn fly or midge lands on them... it's all over! Same thing with flies up to about the size of a blue bottle!

Gardeners' World Web User 01/10/2010 at 09:33

Hi everyone, we're having a few problems with our spam filter at the moment. Please do continue to leave comments - if they don't appear immediately we'll keep fishing them out of the spam folder until the matter has been resolved. Kate

Gardeners' World Web User 09/12/2010 at 15:18

I cannot understand the some people who read Gardeners World magazine can have such small minds. Alexander Sinclair is a breath of fresh air,the way he writes always puts a smile on my face,it is a sad view,chill out and widen your minds and appreciate good writing

Gardeners' World Web User 28/11/2011 at 18:41

Having nearly killed my pitcher plant by not keeping the water topped up I'm now in the strange position of having green flies trying to attack the "fly eating plant". I will continue to wipe them off until its pitchers regrow. Will it then "eat" the flies?