May

Stinging nettle (Urtica dioica)

I have just had my first encounter in 2010 with a stinging nettle and now have a red rash with little white pimples across my hand to prove it! Love them or hate them, we will probably all be stung by nettles during the course of the year as they are, despite our best efforts, a very common and widespread species. I have to say I admire them, but with my hand now tingling badly, I’m not sure that I could honestly say I love them!

Our ancestors have made good use of nettles, discovering all sorts of ways to use them. At this time of year as the young fresh spring growth occurs, large amounts would be picked and used as a vegetable (it is just like spinach) as they are an excellent source of vitamins A and C, calcium, magnesium, iron and many trace elements – perhaps much needed after a long cold winter with little fresh produce. Samuel Pepys wrote in his diary that he had eaten nettle porridge and that “it was very good”! Even today you can find nettles wrapped around certain cheeses such as the delicious Cornish Yarg (not a Cornish word in fact, but “gray” spelt backwards!), which is coated in nettles to help keep the cheese moist and to ward off flies.

Stinging nettles are also, of course, an important food source for some of our best known butterflies such as the small tortoiseshell, red admiral, peacock and comma, and they also host a wide range of other insect species. If you cut down a small patch of nettles in a sunny area around the end of June (checking for caterpillars first!) they will regrow and may well be chosen by the above butterflies to lay eggs on, as they prefer the young new growth for their caterpillars to feed on.

The Romans apparently used to use stinging nettles to help relieve arthritis, and Plymouth University have recently shown that indeed the stings of this plant can have a beneficial effect on sufferers. The sting itself is delivered through a tiny hollow hair much like a hypodermic needle and was always believed to contain just formic acid. Research has shown that most of the sting is actually caused by the chemicals histamine and serotonin, with another ingredient that is still to be identified. Interestingly, the old practice of placing a dock leaf on the affected area to sooth the pain is not as daft as it may seem, as dock leaves contain antihistamine in the sap. If you pick a dock leaf and break it up to release the chemicals and then add some spit to the crumpled up leaf prior to applying it gently to the stings, both the antihistamine and the natural healing properties of saliva will ease the pain.

Although most gardeners hate nettles, they can actually be quite useful, especially to the organic gardener. If you collect at least half a pound of young nettles and soak them in a bucket of water for a week, then strain the leaves out, you are left with a liquid manure that is rich in nitrogen and can also be used undiluted as a spray against aphids. The leaves can be added to the compost heap to make the most of any leftover nitrogen and because nettles are a good activator – in other words they speed up bacterial activity and thus shorten the time needed to make the compost.

Believe it or not, nettles have also been used to control head lice, stimulate hair growth, produce a strong flax-like fibre and make paper, string and cloth. They have been used in the manufacture of sugar, starch, protein and ethyl alcohol. Oil obtained from nettles has been used for lighting and the juice of the plant, boiled with salt, can act as a rennet substitute as it will curdle milk. This same juice, if rubbed into the small cracks of a leaky wooden tub, will coagulate and make the tub watertight. Finally, the leaves can make a wonderful green dye and the roots produce a yellow dye!

So, perhaps the next time you get stung by a stinging nettle, you might still cuss the plant, but also stop to marvel at its endless qualities too!

Peter Thompson
Advisory