Stinging nettles

Nature Notes from the Rec, October 24

A sometimes painful dilemma

So what is it about this native perennial that makes it so unpopular? Well, for a start, it's not seen as being particularly attractive; it's tall and leggy, with bunches of understated green flowers that definitely don't have the 'Wow' factor. And then there's that ability to inflict a painful rash through stinging hairs on the leaves and stem. If it was an endangered species we might be prepared to overlook these things and even cherish it.....a perverse tendency we have when things are rare or threatened. But nettles are all too common and tend to be very invasive.

Given this, why are we trying to nurture a patch of nettles in the corner of the garden area? Aside from the fact that this is a plant that has had many beneficial uses for humans over hundreds of years, it is also great for wildlife. The caterpillars of many species of butterflies and moths, use nettle leaves as their main, or only, source of food. These include the Comma, Painted Lady, Red Admiral and Tortoiseshell butterflies, and moths such as the Mother of Pearl, Burnished Brass and Jersey Tiger. Many other insects such as ladybirds, and beetles; one aptly named the Nettle bug, also benefit.

The Latin name of the Stinging Nettle is Urtica dioica which refers to two of its attributes. Urere means 'to burn', and dioica means 'two houses', because the male and female flowers are borne on separate plants. It can grow up to 2 metres tall and prefers damp soil which is rich in phosphorous. For this reason, it is found close to human habitation where land has been fertilised through occupation and agricultural practices. The phosphorous in the soil can persist for very long periods, and archaeological sites still densely covered in nettles, are found hundreds of years after they've been abandoned.

This plant has both stinging and non-stinging hairs, the former being used to protect it from predators. They are called trichomes; they are hollow and act like a hypodermic syringe. On contact, the brittle tip of the hair snaps off injecting an irritant fluid, including formic acid and histamine, into the skin. The result is usually pain, swelling and redness of the affected area, which is known as nettle rash or urticaria. It is unpleasant but rarely serious

Stinging nettles spread either vegetatively with their creeping yellow rhizomes, or through wind pollinated seeds. The flowers appear in dense whorled clusters between May and September, and emerge from a point where the leaf joins the stem The female flowers, that give rise to the seeds, form large, pendulous clusters that are greenish in colour. The male flowers occur in less dense clusters, are slightly less drooping and sometimes have a purple tinge. (See photos) Nettle seeds are popular with foragers being very rich in nutrients, as is the rest of the plant. Over the centuries, humans have used stinging nettles in cooking, for its medicinal properties, and to make compost and fibre.

And the humble nettle features in art and literature, including references in Shakespeare, the  Bible and Aesop's fables: although not all are positive, it has to be said!  It has found its way into everyday language, such as when we are urged to summon up courage by "grasping the nettle" or when we are feeling irritated, or "nettled". Some place names and surnames also owe their existence to this contentious weed, such as Nettlecombe in Gloucestershire.

Contentious it may be, but its value to wildlife is considerable. So if you're able, please allow nettles a less-used corner of your garden, and remember that those which have escaped the mower at the Rec, have been left intentionally. Butterfly numbers hit an all time low this year and need all the help we can give them. We hope our sunny patch of nettles will provide a welcome spot in which moths and butterflies can lay their eggs, so that we can continue to enjoy the sight of these beautiful insects at the Rec. So please let's embrace those nettles........metaphorically speaking of course!