Hairy Willow-Herb

hairy willow herb plant
hairy willow herb flower
hairy willow herb habit

Hairy Willow-Herb

Epilobium hirsutum

Information Sheet (PDF)


Colorado List A - Eradication required in Jeffco


General

  • Family: Evening Primrose Onagraceae
  • Introduced from Europe as an ornamental
  • Semi-aquatic herbaceous perennial


Common Names

  • Great willowherb, Codlins and cream


Habitat

  • Colony forming
  • Found in wetlands, drainages, and rights-of-way
  • Perennial forb
  • Very invasive
  • Was sold as an ornamental in the past


Plant


Vegetation

  • 1/2 inches wide and up to 4 inches long
  • Leaves opposite and lanced-shaped with toothed edges
  • Mature plants up to 6 feet tall
  • Stem erect and branched with soft hairs


Roots

  • Fibrous roots, rhizomes, and stolons


Flower

  • ½ - 1 inch wide
  • Pink or purple with white center and notched petals
  • Season: June to August


Seed

  • White silky tuft in long seedpod


Seedling

  • Plants re-sprout from roots in the spring


Reproduction

  • Seed, rhizomes and stolons


Control


Biological

  • None


Chemical


Cultural

  • Prevention - maintain health of site
  • Removal - bag and dispose of plants if seeds have started to develop


Mechanical

  • Burning - N/A
  • Grazing - N/A
  • Mowing - Young plants prior to flower formation


Use all chemicals according to the manufacturer's label. No specific recommendation or endorsement is made or implied by listing methods or products.