Urtica gracilis

Aiton

Slender nettle

Urticaceae Edible: Leaves Potential hazards — see below 35,362 iNaturalist observations

iNaturalist· cc-by-nc

iNaturalist· cc-by

Summary

Urtica gracilis, commonly known as the slender nettle, tall nettle, or American stinging nettle, is a perennial plant without woody stems that is well known for the unpleasant stinging hairs on its leaves and stems. It is native to much of the North American continent from Guatemala northwards and temperate areas of South America. It is easily confused with the visually very similar Eurasian species Urtica dioica and is still listed in some resources as a subspecies of this plant. However, genetic analysis and experiments show that they are genetically distinct.

Description

A herb. It grows 50-200 cm high. The leaves are opposite and simple. They are narrowly sword shaped and have coarse teeth. They have stinging hairs. The flowers are small and green. They occur as many together in branched clusters. The male and female flowers can be on one plant or separate plants. The fruit are small and flattened.

Edible Uses

Young leaves are best cooked, making a nutritious spinach substitute or a useful addition to soups and stews. The plant is high in vitamins and minerals. Harvest only young leaves and wear stout gloves to avoid being stung. Fresh leaves have stinging hairs, but thorough drying or cooking destroys them completely. Nettle beer can be brewed from the young shoots.

Medicinal Uses

The leaves are alterative, antiasthmatic, antidandruff, antispasmodic, diaphoretic, diuretic and expectorant. A decoction of the leaves has been used to treat colds. Fresh leaves rubbed or beaten onto the skin have been used for rheumatism through urtification — the resulting irritation acts as a counter-irritant, drawing blood to the area to help remove rheumatic toxins, while the formic acid from the nettles is believed to benefit affected joints directly. An infusion of the roots has been used for dysentery and urine retention, and a decoction of the root used as a bath treatment for rheumatism.

Known Hazards

As every other species of Urtica, it has stinging hairs that irritate the skin. This is prevented by cooking it and using the young leaves instead, because older leaves develop cystoliths which act as an irritant to the kidneys.

Distribution

It grows in damp soils and waste places.

Where It Grows

Canada, North America, USA,

Cultivation

We have very little information on this species and do not know if it will be hardy in Britain, though judging by its native range it should succeed outdoors in most parts of the country. It is closely related to U. dioica, and may be no more than a part of that species. The Flora of North America treats this taxon as a sub-species of U. dioica. The following notes are based on the general needs of the genus. Prefers a nitrogen-rich soil. The best fibre is produced when plants are grown on deep fertile soils. Dioecious. Male and female plants must be grown if seed is required.

Propagation

Sow seed in spring in a cold frame, barely covering it. Prick seedlings into individual pots when large enough to handle and plant out in summer. Division can be done at almost any time in the growing season — plant divisions straight into their permanent positions.

Other Uses

A strong flax-like fibre from the stems is used for string, cloth and good quality paper. It is harvested as the plant begins to die down in early autumn and retted before the fibres are extracted. The following uses are listed for U. dioica but are considered almost certainly applicable here too. Residual plant matter after fibre extraction provides biomass for manufacturing sugar, starch, protein and ethyl alcohol. Seed oil is used as an illuminant. The plant is an essential ingredient of 'QR' herbal compost activator, a dried powdered herbal blend that accelerates bacterial activity in compost heaps. Leaves make a valuable compost addition and can be soaked for 7–21 days in water to make a nutritious liquid plant feed that also serves as an insect repellent and foliar feed. The growing plant raises the essential oil content of neighbouring plants, improving their resistance to insect pests. Flies are repelled by the plant, and freshly cut stems have been kept in food cupboards for this purpose. Plant juice or a decoction boiled in strong salt solution curdles milk as a rennet substitute; rubbed into leaky wooden tub seams it coagulates and seals them. Infused leaves make a hair wash used as a tonic and antidandruff treatment. A permanent green dye comes from a decoction of leaves and stems; a yellow dye from the root boiled with alum.

Synonyms

U. dioica gracilis.

References (4)

Cormack, R. G. H., 1967, Wild Flowers of Alberta. Commercial Printers Edmonton, Canada. p 67
Elias, T.S. & Dykeman P.A., 1990, Edible Wild Plants. A North American Field guide. Sterling, New York p 79
Hort. kew. 3:341. 1789
Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/