Hardy perennial and annual plants, which reach 1—5 ft (30—145 cm), having pointed toothed leaves and green flowers in summer. U. mens is annual, 1 ft (30 cm) and flowers all season; U. dioica is perennial; both are native, but U. pilulifera was introduced by the Romans and has flowers in rounded clusters. It is annual and grows to 2 ft (60 cm).
Leaves picked young are a substitute for spinach; they contain iron and silicic acid, and are good for cleaning the blood in spring. They are a good diuretic. The fibres were once used to make into a kind of linen, before cotton came into widespread use. The stinging feeling produced by the leaves is due to a substance similar to histamin and similar to the hormone secreted by the pancreas.
The Roman nettle has the story attached to it that the Roman soldiers, having been told that the climate of England was bitterly cold, brought quantities of this species to rub on them, producing a warm tingling sensation. It was thought to represent envy in mediaeval flower symbolism, and Culpeper thought that ‘seed being drunk was a remedy against hemlock, nightshade, mandrake or such herbs as stupify the senses’.
Cultivation, As it is such a well known weed, advice on this seems unnecessary.