Stinging nettle (Urtica dioica) is one of the rare plants whose flowers are greenish. This perennial is native to and found throughout most of North America and is also native to parts of Asia and Europe. Stinging nettle prefers rich, moist soils and is found in meadows, in ditches, along stream banks, barnyards and other disturbed areas with good soil. These stinging nettle plants were growing along the Tule River (Shasta County CA).
Growing from three to ten feet in height, stinging nettle has a strong system of spreading rhizomes and can form dense stands. The opposite, lance-shaped leaves have coarsely saw toothed margins and prominent stipules (appendage at the base of the leaf stalk). Droopy, stringy clusters (spikes) of flowers are found growing in the leaf axes and at the stem tips. Male and female flowers are found in separate spikes with female spikes above the male spikes on the stem. The fruits are lens shaped achenes (dry, one-seeded fruit).
The undersides of stinging nettle leaves and the stems are covered with thousands of tiny, hollow, needle-like hairs containing antigenic proteins and formic acid (think red ants). When skin comes in contact with the hairs, contact dermatitis with burning pain and tiny blisters results. After about an hour the pain is gone. I handled these plants extensively with the tips of my fingers while taking the pictures even though I knew what the result would be. After about ten hours my fingers were still stinging, but were fine by the next morning. Stinging nettle is a nuisance to hikers and other recreationalists.
If the leaves and stems are dried or cooked before ingestion stinging nettle is edible as a potherb or as a tea. The plants are more palatable when young because as stinging nettle ages it becomes fibrous. During and after the bloom gritty particles called cystoliths form and also make older plants less edible. Stinging nettle is high in iron, calcium, potassium and several vitamins so was often used as a “spring tonic”. I have eaten cooked stinging nettle and find it acceptable, but definitely not something I would make a special effort to gather and use.
Among certain Native American tribes persons suffering from chronic arthritis would whip themselves with stinging nettle. They believed that the irritating stinging nettle constituent would go through the skin and react with the arthritis to neutralize the chronic pain. The theory was wrong but their stinging skin probably diverted their attention from the arthritis pain – at least temporarily.