This herbaceous perennial is a fantastic, nutritious, multi-functional plant (although known as a weed to some). The leaves are distinctive with their strongly serrated margin, and both leaves and stems are hairy with a mixture of non-stinging and stinging hairs. The tips of the latter come off when touched, transforming the hair into a needle that can inject several chemicals causing a painful sting, hence the common name of stinging nettle or stinger. Despite this the plant has been used in many ways across many cultures. Not only is it edible but it is highly nutritious, containing vitamins A and C, iron, potassium, manganese, and calcium, and up to 25% protein (dry weight). Mature leaves contain about 40% α- linolenic acid, a valuable omega-3 acid, with the seeds containing much higher levels of fatty acid than leaves. Only the young leaves should be harvested, and thick gloves should be worn to do so!
Probably best known as a soup ingredient, nettle can be used in any way other green vegetables such as spinach are used, for example in pesto, polenta, puree, borek (small pasties), and spanokopita. It can also be dried for winter use as a vegetable, or for tea, and used as an ingredient in beer. Nettles have a long history of use in the home as a herbal remedy. Usually administered as a tea, the leaves have a cleansing tonic and blood purification function. The whole plant is antiasthmatic, antidandruff, astringent, depurative, diuretic, galactogogue, haemostatic, and hypoglycaemic. An infusion of the plant is very valuable in stemming internal bleeding, it is also used to treat anaemia, excessive menstruation, haemorrhoids, arthritis, rheumatism and skin complaints, especially eczema.
Due to their accumulated mineral content, nettles can be used as a compost activator or to make a liquid fertilizer, providing nitrogen, magnesium, sulphur, and iron. They are used in the Biodynamic fertility preparation 504. Given enough moisture and fertile soil they can be harvested a couple of times a season as a ‘chop and drop’ for mulch, although it is said that cutting them three times a year for three years is the way to get rid of them if considered a weed. They can also help to attract butterflies, in particular the endemic Red Admiral (Kahukura). The natural host plant is the native Urtica ferox (Ongaonga), but the larvae will also eat this introduced species of nettle.
Nettle stems contain a fibre which has been used to make clothing for at least 3000 years. German Army uniforms were almost all made from nettle during World War I due to a potential shortage of cotton! The plant can also be used for making string and paper. It is harvested as the plant begins to die down in early autumn and is retted before the fibres are extracted. The practice fell into disuse as the fibre is produced in less abundance than from flax and is also more difficult to extract. However some craftspeople are reviving the practice, see for example nettlecraft.com.
The plant matter left over after the fibres have been extracted are a good source of biomass and have been used in the manufacture of sugar, starch, protein and ethyl alcohol. Nettles may also be used as a dye plant, producing yellow from the roots, or yellowish green from the leaves.
The juice of the plant, or a decoction formed by boiling the herb in a strong solution of salt, will curdle milks and thus acts as a rennet substitute. This same juice, if rubbed into small seams of leaky wooden tubs, will coagulate and make the tub watertight again, perhaps a slightly less useful function than the former these days!
The plant can spread by seed, rhizomes and stolons to colonise patches of ground, and can re-colonise quickly after fire, but it does require even moisture and shade. Height up to 1.5m, dying down completely in winter.
9cm pot. Certified organic plant.
See here for a useful article on the uses of nettles, containing lots of further links.
Main photo: https://www.flickr.com/photos/brewbooks/2544110170
Fibre products: 16dde1f4a4b-nettle-fibre-products-adjusted.crop700x500