White vervain is a 3-to-6-foot-tall annual, biennial, or short-lived perennial commonly found in woodland edges, old fields and pastures, swamps, thickets, disturbed areas, and along roadsides. It has a dusty-gray, slightly weedy appearance as referenced by its species name; urticifolia refers to the plant's resemblance to the common nettle (genus Urtica; another common name is nettle-leaved vervain). When in bloom, the long, lanky stems sprawl in many directions. While some consider this plant to be a weed, it has high ecological value and can add a fine-textured airiness to the landscape. The blooming period occurs from mid-summer to early fall and lasts about 1½ months. Only a few flowers bloom at the same time. The tiny flowers provide nectar for native bees, butterflies, wasps, and flies. The seeds are eaten by birds, and the leaves are a food source for 11 species of Lepidoptera larvae and the two-striped grasshopper. Deer find the bitter leaves to be distasteful.
Numerous long, slender spikes of minute flowers form at the ends of stems and axillary branches. Flowers are scattered along the length of the stem, giving the spikes an airy appearance. The deeply serrated leaves smell like puffballs when crushed.
White vervain is found in old fields, pastures, roadsides, thickets, wood edges, and other disturbed places. The species prefers rich, heavy soils . It reproduces by seeds and spreads by short rhizomes.
Plant Characteristics:
Grows 3-6' tall.
Prefers full or part sun.
Prefers moist to average, loamy soils containing clay or silt.
Flowers bloom August-September and are about 1/10 inch wide. Widely-separated fruits are scattered along the stem. The nutlets separate into 4, single-seeded sections and remain attached to the spike.
Oblong-oval leaves have hairs on the upper surface and edges; veins are on the lower surface. . Young leaves and stems have dull purple staining.
Slender stem are 3-5' tall, square, grooved, slightly hairy, and sparsely branched. They often appear purplish.
Wildlife Value:
Host plant for 11 species of Lepidoptera larvae, including specialist verbena groundling, verbena bud moth, and common buckeye.
Medicinal, Edible, and Other Uses:
Vervain has been used traditionally to treat the flu and gynecological issues.
Resources:
OSU: https://weedguide.cfaes.osu.edu/singlerecord.asp?id=36
Wild Ones: https://rivercitygrandrapids.wildones.org/natives-to-know-white-vervain-verbena-urticifolia/#:~:text=White%20vervain%20has%20long%20been,plant%20for%20the%20native%20garden.
Illinois Wildflowers: https://www.illinoiswildflowers.info/savanna/plants/wh_vervain.htm
Friends of the Wildflower Garden: https://www.friendsofeloisebutler.org/pages/plants/whitevervain.html