Origin:
Urtica dioica var. dioica is native to Europe, but U. dioica var. procera is the common North American variety and is considered naturalized.
Biology:
A perennial plant, propagating and spreading either by seeds or by rhizomes. Rhizomes are rapid growers, and may spread by 6 to 7 feet in a single year. Nettle prefers damp locations, and grows easily in irrigation or drainage ditches, along riverbanks, as well as roadsides and waste places. Its leaves are covered on the lower surfaces with stinging hairs, that break off upon contacting skin, releasing a mixture of toxins into the skin. Stinging hairs also occur along the densely hairy stems.
Identification:
Very similar to burning nettle, but leaves are generally narrower, being much longer than they are wide. Mature plants may grow to 9 feet tall, with stiff bristly hairs covering the thick, strong stems. Leaves are up to 5 inches long, lance-shaped and rounded at the base. The margins are lined with distinct serrations or teeth. The upper surface is only slightly hairy, while the lower surface is covered with the longer hairs, many of which are stinging hairs. Leaves are on a long stalk, and at the base of the stalk there are small leaf-like structures as well, about ½ inch long. Flowers occur in clusters arising from the base of the leaf, and are either male or female clusters. The male clusters are long and arranged more loosely, while female clusters are short and compact. Flowers are very small and whitish green.
Characteristicts Important to Control:
A perennial spreading by very fast growing, underground rhizomes.
