Ohio Perennial and Biennial Weed Guide

Family:

Vervain Family (Verbenaceae)

Other Names:

None.

Origin and Distribution:

White vervain is native of North America. White Vervain is common in eastern and central parts of the U.S. and rare on the west coast. It is also distributed throughout Ohio. White vervain establishes in old fields, pastures, roadsides, thickets, wood edges, and other disturbed places. The species prefers rich, heavy soils

Plant Description:

White vervain is an upright perennial. Among the characteristics it shares with other vervain species are small flowers consisting of 5 united petals in the form of a slender tube with a flared top. Flowers are located in dense spikes at the end of square stems. Fruits are nutlets that separate into 4, single-seeded sections and remain attached to the spike. White vervain has oblong-oval leaves, small white flowers, airy spikes, and widely-separated fruits scattered along the stem. It reproduces by seeds and spreads by short rhizomes (horizontal underground stems).

• Root System:

  Roots are fibrous. Adventitious roots appear early at the soil surface and soon equal the taproot in length.

• Seedlings and Shoots:

  Young leaves have hairs on the upper surface, edges, and veins on their lower surface. If crushed, leaves smell like puffballs. Young leaves and stems have dull purple staining.

• Stems:

  Stem are 3 to 5 feet tall, slender, erect, square, grooved, slightly hairy, and have few branches. Stems often appear purplish

• Leaves:

  Leaves are opposite (2 leaves per node), 1 to 5 inches long, oblong-oval, and have deeply-serrated edges.

• Flowers:

  Flowers are about 1/10 inch wide and white. They consist of 5 petals that are united forming a slender tube with a flared top. Numerous, open, long, slender spikes of small flowers form at the ends of stems and axillary branches. Flowers are scattered along the length of the stem giving spikes an airy appearance.

• Fruits and Seeds:

  Scattered along the length of the spike are widely-dispersed fruits that separate into 4 oval nutlets. Nutlets are reddish-brown, single-seeded, and have a netted surface.

Biology:

White Vervain flowers in July through September.

Toxicity:

None known.

Facts and Folklore:

• Vervain was very popular in European folklore. People wore necklaces of the flowers as charms to cure headaches, prevent snake bites, and bring general good luck. Priests and Druids were said to use it during rites and incantations.

• The plant was discovered on the Mount of Calvary, where it was used to dress the wounds of crucified Jesus Christ.

• When medicines were in short supply during the Revolutionary War, doctors used vervain as an emetic and expectorant with favorable results.

• Nearly 200 species in the genus Verbena are found in the New World. Many of these species have been hybridized and cultivated by New World inhabitants.