Most people know that nettles sting. Just brushing against a leaf can cause a burning feeling and reddening of the skin. It’s surprisingly painful. But what makes nettles sting?

Each leaf is covered in tiny, brittle hairs, like minute hypodermic needles. When you brush against them, the tips break off, releasing a venom that causes the sting. Luckily, nature provides a cure. Dock leaves are often found growing near nettles and docks contain a chemical that reduces the sting by cooling the skin.

So effective is the sting of nettles that grazing animals (with the exception of goats and very hungry sheep) keep away from them. This makes sure the plant doesn’t end up in cows’ stomachs and it makes a nettle bed an ideal habitat for some 40 species of insects which can move between the spines without activating the sting. These insects provide food for butterflies and ladybirds. So, although gardeners think nettles are a troublesome weed, they actually create a nature reserve that brings welcome visitors to their gardens.

Nettles have other uses. Herbalists use them to cure arthritis. Dried nettle leaves can help cure asthma. Powdered leaves stop bleeding. Young nettles are rich in calcium and iron and can be used to make soup. In the past, people in Scotland used nettle stems to weave table cloths and some say Germans used them during the First World War to make soldiers’

uniforms. The stems and leaves can also be boiled to make a green dye while the roots make a yellow dye - which is yet another reason why nettles have their uses, and why we should be nice to nettles.

Follow-up

* Write a prayer in praise of nettles and their place in the ecological system.

* Wearing gloves and long trousers, study a nettle patch to discover its wildlife.

* Learn to recognise different types of butterfly.

* Nettles have their own website: www.nettles.org.uk This includes recipes, an art competition and suggestions for involvement in Nettle Week. CONE (which maintains the site) will advise schools on the development of school grounds to create wildlife habitats which can be used across the curriculum: www.workingwithwildlife.co.uk