All Species

Yellow Hawkweeds (Meadow, Narrowleaf, and Mouse-ear)

Hieracium caespitosum/umbellatum/pilosella
Narrowleaf Hawkweed, 2010 AKNHP

Why is it a problem?

  • Spreads by above and/or belowground horizontal stems, produces 4-8 new shoots every year, and can resprout from root fragments
  • Spreads by seed (number varies by species, ~20-600 per plant)
  • Dispersed by wind and wildlife, and on clothing and equipment
  • Produces chemicals that inhibit the growth of other species
  • May alter soil nutrients and pH
  • Forms dense mats, outcompeting native plants, which reduces biodiversity and forage value for grazing animals
  • Found along roads, lawns (garden escapee), pastures, meadows, forest edges and clearings; easily establishes in disturbed sites then spreads into adjacent undisturbed areas
  • Can hybridize with other native and nonnative hawkweed species

How do I manage this plant?

  • Clean clothing and equipment before leaving a contaminated site
  • Mowing can prevent seed production, but promotes flowering and vegetative spread
  • Cutting and digging are ineffective control methods, as plants will resprout from small root fragments
  • Most effective control method is selective herbicide
  • Monitor for several years, as plants are likely to re-establish from the seed bank and root fragments

More info on species biology

Photo credit for single Meadow Hawkweed plant image: wiki commons, Gerhard Nitter. Photo credit for field of Meadow Hawkweed image: Linda Wilson, University of Idaho, Bugwood.org