Wood Nettle

This herbaceous 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 lower to middle leaves are alternate, while the upper leaves are opposite. These leaves are up to 6" long and 4" across; they are medium to dark green, ovate-cordate to oval-ovate in shape, and coarsely serrated or serrated-crenate. Young leaves are densely hairy and wrinkled in appearance, while older leaves become less hairy and wrinkled with age. Leaf venation is pinnate. The petioles are up to 4" long and abundantly covered with stinging hairs, like the stems. The leaves may have a few stinging hairs as well, particularly along the central veins of their undersides. Some plants have a tendency to loose many of their stinging hairs as the season progresses. Individual plants are either 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" (3 mm.) 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" (3 mm.) 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.