One 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.