Watch List

From "Noxious Weeds of Colorado 11th Edition" as prepared by the Colorado Weed Management Association:

The Watch List is intended to serve advisory and educational purposes only; to encourage the identification and reporting of these species to the Commissioner in order to facilitate the collection of information to assist in determining which species should be designated as noxious weeds.

Watch List species are determined by one of the following;

  • Not known to occur in the state, but their noxious characteristics are recognized by another state or states in the region
  • Has been found to exhibit noxious characteristics in agricultural lands and/or native plant communities similar to those found in Colorado
  • Is suspected to have noxious qualities as determined by the use of a plant assessment process and is present in the state, but its distribution and effect on agricultural and natural lands is undetermined at this time
  • Updates of the state weed law and listed weed species can be obtained from the Colorado Department of Agriculture.

    Access the entire Watch List for photos and detailed descriptions of each species on the list. It is currently comprised of the following 21 species:

  • Asian mustard (Brassica tournefortii)
  • Baby's breath (Gypsophila paniculata)
  • Bathurst burr/Spiney cocklebur (Xanthium spinosum)
  • Common bugloss (Anchusa officinalis)
  • Common reed (Phragmites australis)
  • Flowering rush (Butomus umbellatus)
  • Hairy willow-herb (Epilobium hirsutum)
  • Himalayan blackberry (Ribus armeniacus)
  • Japanese blood grass/cogongrass (Imperata cylindrical)
  • Meadow hawkweed (Hieracium caespitosum)
  • Onionweed (Asphodelus fistulosus)
  • Purple pampasgrass (Cortideria jubata)
  • Scotch broom (Cytisus scoparius)
  • Sericea lespedeze (Lespedeza cuneata)
  • Swainsonpea (Sphaerophysa salsula)
  • Syrian beancaper (Zygophyllum fabago)
  • Water hyacinth (Eichhomia crassipes)
  • Water lettuce (Pistia stratiotes)
  • White bryony (Bryonia alba)
  • Woolly distaff thistle (Carthamus lanatus)
  • Yellow flag iris (Iris pseudacorus)

    Please print and share the Colorado Department of Agriculture's Watch List poster. If you spot any of the species on the list, please report them to the Colorado Department of Agriculture, the Larimer County Weed District or your local weed district office. Early detection and rapid response is the best management practice!