Hairy Willow Herb

(Epilobium hirsutum)

 

   

 

 

Color photograph: Homer D. House. 1918. Wildflowers of New York.

Line Drawing: Britton, N.L., and A. Brown. 1913. An Illustrated Flora of the Northern United States and Canada, Second Edition.

 

Hairy Willow Herb (Epilobium hirsutum L.)

Alien: Native of Europe.

Identification: Flowers magenta (rarely white), relatively large (1.5 to 3 cm. wide) with 4 petals, and a long, thin corolla tube. Petals with outer margin indented. Stigma divided into 4 parts and stamens conspicuous. Flowers arising individually from the leaf axils, not arranged in a terminal raceme. Seedpods elongate, pointing upward. Stem hairy. Leaves usually in opposite pairs, thin and narrow (lanceolate), with toothed outer margins. Plant 3 to 6 feet in height.

Distribution: Throughout southeastern Canada southward to Illinois and Michigan in the west to Maryland in the east.

Habitat: Hairy Willow Herb is found along stream banks and in disturbed habitats such as ditches, roadsides, and empty fields.

Flowering period: July to September.

Similar Species: The flowers of Fireweed are arranged in a terminal raceme and do not arise individually from the leaf axils. The stem is smooth, not hairy, and the leaf margins are smooth, not toothed. River Beauty (Epilobium latifolium) (not treated here) has larger flowers, the leaf margins are smooth, and the leaves are not as elongate.

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