"Stinging nettle" refers to a group of plants with more than 500 members in its genus, though in North America, the name usually refers to a handful of plants that deliver a strong burning and itching sensation when handled. The plant, which occurs both as a native and as several non-native introduced species, has a long history of medicinal use. Recently, the plant has made an appearance on the culinary scene, as well.
Stinging nettle usually refers to one of five distinct plant species. The native American species, California nettle (Urtica dioica ssp. gracilis) is closely related to its introduced European cousin, Urtica dioica ssp. dioica. A second native species, Urtica dioica ssp. holosericea, is found only in Western states, while the others are widely distributed across the country.
Dwarf stinging nettle (Urtica urens) is another European introduction that has made its way across the American continent, while an unrelated plant also called stinging nettle or the tread softly (Cnidoscolus urens) is a member of the spurge family and looks completely distinct from other types of nettles.
With the exception of the tread softly, native and European stinging nettles are distinguished by their hairy, heart-shaped leaves, which also usually have serrated edges. Flowers are pink, purple, white or yellow and are beloved by bees. Stems are square. The plant spreads by woody, vigorous rhizomes that spread underground. Plants grow in moist, forested habitats, though they also frequently appear in pastures and roadside ditches.
Stinging nettle gets its name from the burning sensation that occurs after contact with either the leaves or stems of the plant. Formic acid, the responsible chemical, is also the reason an ant's bite causes irritation and itching. Remedies for the itch include applying a poultice of baking soda; failing that, rubbing human saliva over the affected area brings moderate relief. Applying juice of the nettle itself or of curly dock (Rumex crispus), which frequently grows alongside stinging nettle, are also effective relief measures.
Stinging nettle as a medicinal plant dates back to at least the Roman era, when soldiers traveling to Europe were said to have brought the plant along for use in keeping warm by rubbing it on their skins. The preponderance of historical evidence for the plant's use in medicine comes from medieval times, when teas and powders made from nettle leaves and roots were used to treat ailments, including urinary tract infections, infertility, gout, acne and eczema.
Nettle was also valued for its non-medicinal uses: when boiled with salt, the plant produces a yellow dye.
Today, nettle is available in capsule or powdered form as an herbal supplement. Human trials of plant preparations have been tested by for effectiveness in treating enlarged prostate, osteoarthritis and hay fever. Like any herbal supplement, preparations of nettle are not endorsed by the Food and Drug Administration for treatment of any ailment; however, chemical analysis of the compounds active in nettle show that the plant has reasonable potential to treat people affected by these ailments, according to the University of Maryland Medical Center.
Nettles are considered to be highly nourishing because of their high vitamin and mineral content. Plants also contain relatively high levels of calcium, iodine, iron, magnesium and potassium. Only the young, new tops of plants are suitable for use in cooking; they can be gathered---using gloves---as they emerge in April and May. Before use, nettles require blanching in boiling water, which neutralizes the stinging formic acid. High in chlorophyll, nettles are an attractive and tasty addition to dishes, including soups, pastas and salads, or as a side accompaniment with meat dishes.