Perennial Nettle

Nettle is not only edible but 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.

Due to its accumulated mineral content, nettle can be used as a compost activator or to make a liquid fertilizer, providing nitrogen, magnesium, sulphur, and iron. It is used in the Biodynamic fertility preparation 504. Given enough moisture and fertile soil it can be harvested a couple of times a season as a ‘chop and drop’ for mulch, although it is said that cutting it three times a year for three years is the way to get rid of them if considered a weed. It 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 that 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!