Ohio Perennial and Biennial Weed Guide

Family:

Vervain Family (Verbenaceae)

Other Names:

false vervain, hastateleaf vervain, ironweed, purvain, Simpler's-joy, swamp verbena, wild hyssop.

Origin and Distribution:

Blue vervain is native of North America. BLUE VERVAIN is common in the eastern part of the U.S. and rare west of the Mississippi. Its range includes all of Ohio. The species is found in meadows, pastures, ditches, and shores. It prefers gravelly or heavy loam soils and grows mainly on low ground and other moist places.

Plant Description:

Blue 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. Characteristics distinguishing blue vervain are its lance-shaped leaves, blue flowers, compact spikes, and fruits packed so tightly on the stem that they frequently overlap. It reproduces by seeds and spreads by short rhizomes (horizontal underground stems).

• Root System:

  Roots are fibrous. Adventitious roots arise early from the base of the stem.

• Seedlings and Shoots:

  Young leaves have hairs on the upper surface, edges, and veins on their lower surface. Leaves emit a mushroom-like odor when bruised. Young leaves and stems are often purple-tinged.

• Stems:

  Stems are 2 to 7 feet tall, erect, square, coarsely grooved, covered with short hairs, and branched near the top. Stems often appear purplish.

• Leaves:

  Leaves are opposite (2 leaves per node), 2 to 6 inches long, lance-shaped, serrated around the edge, and rough textured.

• Flowers:

  Flowers are about 1/8 inch across and usually blue (rarely pink). They consist of 5 petals that are united forming a slender tube with a flared top. Stiff, pencil-like spikes of numerous small flowers form at the ends of stems and axillary branches. A few flowers bloom at a time, with the location of the open blossoms progressing steadily toward the tip of the spike.

• Fruits and Seeds:

  Spikes are crowded with overlapping fruits that separate into 4 linear nutlets. Nutlets are reddish-brown, single-seeded, and have a ridged surface.

Biology:

BLUE VERVAIN flowers in June 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.