Nettle family (Urticaceae)
Description: This native perennial plant is about 2-4' tall and either branched or unbranched. The stems are light to medium green and abundantly covered with stiff white hairs that have the capacity to sting when they are rubbed against. The alternate leaves are up to 6" long and 4" across; they are medium to dark green, ovate-cordate to ovate, and coarsely serrated. Young leaves are densely hairy and wrinkled in appearance, while older leaves become less hairy and wrinkled with age. There are 3 prominent veins toward the base of each leaf blade. The petioles are up to 4" long and abundantly covered with stinging hairs, like the stems. The leaf blades may have a few stinging hairs as well.
Individual plants are monoecious (separate male and female flowers on the same plant) or unisexual. The male flowers occur in branching cymes from the axils of the leaves. These cymes spread outward from the stem and they are about the same length as the petioles of the leaves. Each male flower is greenish white to white and less than 1/8" across, consisting of 5 narrow sepals, 5 stamens, and no petals. The female flowers occur in branching cymes toward the apex of the plant. These cymes are erect to spreading and 4" or more in length. Each female flower is more or less green and about 1/8" across, consisting of 4 sepals of unequal size (2 large and 2 small) and an ovary with a long style. The blooming period usually occurs during mid- to late summer. The flowers are wind-pollinated. Each female flower is replaced by a small dry fruit that is curved and ovoid in shape. This plant often forms colonies of variable size.
Cultivation: The preference is partial sun to medium shade, moist conditions, and a fertile loamy soil with abundant organic matter. Because of its stinging hairs and tendency to spread, this is a plant that you would probably not want to plant near the house, except possibly as a privacy barrier.
Range & Habitat: The Wood Nettle is common in central and northern Illinois, but uncommon or absent in parts of southern Illinois (see Distribution Map). Habitats include moist floodplain woodlands, mesic woodlands, shady seeps, and other moist places in wooded areas. Various deciduous trees (e.g., elms, maples, or sycamore) dominate the habitats where the Wood Nettle occurs.
Faunal Associations: The caterpillars of the following butterflies feed on the foliage: Polygonia comma (Comma), Polygonia interrogationis (Question Mark), and Vanessa atalanta (Red Admiral). White-Tailed Deer also graze on the foliage of Wood Nettle occasionally, notwithstanding the stinging hairs. When this plant forms dense colonies in wooded areas, it provides valuable cover for wildlife.
Photographic Location: A floodplain woodland in Vermillion County, Illinois. The Wood Nettle in the photographs wasn't in bloom. The plant with narrow leaves on the lower- to middle-right of the lower photograph is Galium aparine (Cleavers).
Comments: This native plant is often mistaken for the introduced Urtica dioica (Stinging Nettle). Both species have stinging hairs and a similar appearance. However, the Wood Nettle has alternate leaves, while Stinging Nettle has pairs of opposite leaves along its stems. There are also differences in the characteristics of their flowers. Another similar species, Boehmeria cylindrica (False Nettle), also has opposite leaves, but it lacks stinging hairs altogether. Like other members of the Nettle family, the Wood Nettle lacks showy flowers because they are wind-pollinated, rather than pollinated by insects. Some people may regard this species as an undesirable woodland weed because of its stinging hairs and unassuming appearance, but it has some ecological value as indicated above.