Urtica thunbergiana
Siebold. & Zucc.
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(c) nanhu3742, some rights reserved (CC BY-NC)
iNaturalist· cc-by-nc
(c) 戴勝, some rights reserved (CC BY-NC)
Summary
Source: WikipediaUrtica thunbergiana, also known as the Japanese nettle or hairy nettle, is a species of perennial herbs in the family Urticaceae. It is found in Japan, China and Taiwan. The habitat of the species is moist forests in the mountains. It is in flower from July to September, and its seeds ripen from August to October. The larvae of Vanessa indica, a species of butterfly, are known to feed on U. thunbergiana. Chinese common names for U. thunbergiana translate to "biting cat", "biting nettle", and "stinging herbs" due to the stinging hairs on the plant that can cause skin pain, redness, burning or itching. Usually, the stinging sensation lasts for about 2 to 4 hours, and some people even feel the pain for 1 to 2 days, depending on the individual's constitution. As with other species in the genus, U. thunbergiana can also be used as a food ingredient, because boiling water can destroy its toxicity. In Taiwan, in addition to flavored soup, it is also made into flavored bread, Chinese shortbread or crispy fried leaves. From 2016 to 2017, Shei-Pa National Park's headquarters commissioned a survey of animals along the Mount Dabajian hiking trail. In this investigation, a video of a Taiwan serow feeding on U. thunbergiana was recorded.
Description
A perennial nettle reaching 80cm tall, hardy in all but the most severe winters. Produces male and female flowers on separate plants from July to September, with seeds ripening August to October. Thrives in light, medium, or heavy soils across a wide pH range, tolerating semi-shade and preferring consistently moist conditions. Wind-pollinated and requires both sexes for seed production.
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 harvested, and stout gloves should be worn to avoid stings. Although fresh leaves carry stinging hairs, thorough drying or cooking destroys them entirely. 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, Korea,
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. Plants can be monoecious or 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 very easy, 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 speed up bacterial activity and reduce composting time. The leaves are an excellent compost addition and can be soaked in water for 7–21 days to produce a nutritious liquid plant feed that acts as both an insect repellent and a foliar feed. The growing plant raises the essential oil content of nearby plants, making them more resistant to insect pests. Freshly cut stems repel flies and have been used 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 works 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
Ira-Kusa, Mao Hsien, T'An Ma
References (2)
- Liu, Yi-tao, & Long, Chun-Lin, 2002, Studies on Edible Flowers Consumed by Ethnic Groups in Yunnan. Acta Botanica Yunnanica. 24(1):41-56 (As Urtica macrorrhiza)
- Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/
