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Common Name:

General Information

Urtica serra is a perennial plant that can grow up to 1.50 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

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[].

Botanical References

,

Range

Western N. America.

Habitat

Wet places, mainly between 1500 - 3000 metres, in coniferous forests in California[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.50 m
Pollinators	Wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

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. Some doubt must be cast over the validity of this taxon, it is mentioned in the Flora of North America as having been misapplied to U. dioica holosericea[]. 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[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

Young leaves - cooked[]. A very nutritious food, high in vitamins and minerals, it makes an excellent spinach substitute and can also be added to soups and stews. Only use the young leaves and wear stout gloves when harvesting them to prevent getting stung. Although the fresh leaves have stinging hairs, thoroughly drying or cooking them destroys these hairs.
Nettle beer is brewed from the young shoots[].

Medicinal

The fresh leaves of nettles have been rubbed or beaten onto the skin in the treatment of rheumatism etc[]. This practice, called urtification, causes intense irritation to the skin as it is stung by the nettles. It is believed that this treatment works in two ways. Firstly, it acts as a counter-irritant, bringing more blood to the area to help remove the toxins that cause rheumatism. Secondly, the formic acid from the nettles is believed to have a beneficial effect upon the rheumatic joints.

Other Uses

A strong flax-like fibre is obtained from the stems[]. Used for making string and cloth, it also makes a good quality paper[]. It is harvested as the plant begins to die down in early autumn and is retted before the fibres are extracted[, ].

The following uses have been listed for U. dioica, but they are almost certainly also applicable to this species.

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[].
An oil obtained from the seeds is used as an illuminant[].
An essential ingredient of 'QR' herbal compost activator[]. This is a dried and powdered mixture of several herbs that can be added to a compost heap in order to speed up bacterial activity and thus shorten the time needed to make the compost[]. The leaves are also an excellent addition to the compost heap[, , ] and they can be soaked for 7 - 21 days in water to make a very nutritious liquid feed for plants[]. This liquid feed is both insect repellent and a good foliar feed[, , ].
The growing plant increases the essential oil content of other nearby plants, thus making them more resistant to insect pests[, , ].
Although many different species of insects feed on nettles, flies are repelled by the plant so a bunch of freshly cut stems has been used as a repellent in food cupboards[].
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[].
A hair wash is made from the infused leaves and this is used as a tonic and antidandruff treatment[, ].
A beautiful and permanent green dye is obtained from a decoction of the leaves and stems[, ].
A yellow dye is obtained from the root when boiled with alum[, ].

Propagation

Seed - sow spring in a cold frame, only just covering the seed. Prick out the seedlings into individual pots when they are large enough to handle, and plant them out in the summer.
Division succeeds at almost any time in the growing season. Very easy, plant them straight out into their permanent positions.