Urtica platyphylla

Wedd.

Urticaceae Edible: Leaves Potential hazards — see below 369 iNaturalist observations

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Summary

A tall perennial nettle reaching 1.8 m, frost-hardy and vigorous. Dioecious requiring both male and female plants for seed production, with wind pollination and non-self-fertile flowers. Tolerates light sandy, medium loamy, and heavy clay soils across mildly acidic to basic pH ranges. Grows in semi-shade or full sun and thrives in moist soil conditions.

Description

Edible Uses

Young leaves are cooked and eaten — a highly nutritious food, rich in vitamins and minerals, that serves as an excellent spinach substitute and can be added to soups and stews. Only young leaves should be used, and stout gloves should be worn during harvest to avoid stings. Although fresh leaves carry stinging hairs, thorough drying or cooking destroys them completely. The young shoots are used to brew nettle beer.

Medicinal Uses

None known.

Known Hazards

The leaves of the plants have stinging hairs, causing irritation to the skin. This action is neutralized by heat so the cooked leaves are perfectly safe and nutritious. However, only young leaves should be used because older leaves develop gritty particles called cystoliths which act as an irritant to the kidneys.

Distribution

It is a temperate plant.

Where It Grows

Asia, China, Japan,

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. 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 once large enough to handle, then plant out in summer. Division can be carried out at almost any point in the growing season — it is straightforward, and divisions can go directly into their permanent positions.

Other Uses

The stems yield a strong flax-like fibre used for string, cloth, and good-quality paper. It is harvested as the plant begins to die back in early autumn and retted before the fibres are extracted. The leftover plant matter is a useful source of biomass and has been used in the manufacture of sugar, starch, protein, and ethyl alcohol. Oil from the seeds serves as an illuminant. The plant is an essential ingredient in 'QR' herbal compost activator — a dried, powdered herbal blend added to compost heaps to accelerate bacterial activity and reduce composting time. The leaves are an excellent compost addition and can be soaked in water for 7–21 days to make a nutritious liquid plant feed that also functions as an insect repellent and foliar feed. The growing plant raises the essential oil content of nearby plants, increasing their resistance to insect pests. Freshly cut stems repel flies and have been placed in food cupboards for this purpose. The plant's juice, or a decoction made by boiling it in a strong salt solution, curdles milk and acts as a rennet substitute; the same juice rubbed into leaky wooden tubs coagulates and makes them watertight. A hair wash from an infusion of the leaves is used as a tonic and antidandruff treatment. A permanent green dye is obtained from a decoction of the leaves and stems; a yellow dye comes from the root boiled with alum.

Also Known As

Mose

References (2)

Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/
Williams, D., 2017, Ainu Ethnobiology. Contributions in Ethnobiology. Society of Ethnobiology. p 145