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Hairy willow herb

(Epilobium hirsutum)

Photo of hairy willow herb
Photo credit: Eleanor S. Saulys

A semi-aquatic perennial herb that grows 3-6' tall, with fine, soft hairs covering the entire plant. Stems are tall and branching. Grows in open, moist habitats.

Overview map of hairy willow herb classification in WI
Prohibited (red) and restricted (orange) counties

Other names for this plant include:

  • Common names: codlins and cream, European fireweed, excellent willow herb.

Classification in Wisconsin: Prohibited/Restricted (Restricted in Brown, Calumet, Door, Kenosha, Kewaunee, and Manitowoc counties; Prohibited elsewhere).

Ecological Threat
  • It forms dense, monotypic stands in open riparian areas along streams, ditch banks, wetlands and moist waste places.
  • It can be found in undisturbed natural areas due to the seed quickly spreading by wind, water or transported by humans or animals.

Leaves: Opposite and stalkless, with sharply toothed edges and a prominent central vein. They are oblong-lance shaped, 2-5" long and most expansive below the mid-point.

Flowers: Numerous 0.75" wide, rose-colored flowers arise from the leaf axils. Each flower has four notched petals, four sepals and a white four-lobed stigma rising above the bloom—blooms in mid-late summer.

Fruits & seeds: Fruit is a 2-3" long, tubular capsule containing many tiny, oblong, flattened seeds, each with a tuft of silky white hairs aiding wind dispersal.

Roots: Large root system with branching rhizomes that grow up to 2' long.

Similar species: Native fireweed (Epilobium angustifolium) can be distinguished from hairy willow herb by its alternate leaves and multiple stalked flowers arranged in a terminal raceme.


Mechanical: Hand pulls or digs, removing all plant parts. Mowing within three weeks of flowering can effectively eliminate annual seed production. Avoid control measures once the seed has matured.

Chemical: Foliar spray is a broad-spectrum herbicide that can translocate into roots and rhizomes, such as glyphosate or imazapyr.

Sources for content:
  • Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. The University of Wisconsin Press. 2005. Pg. 135
  • Invasive Plant Atlas of New England: Hairy willow-herb [exit DNR].
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