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​Consider the noxious weed impact examples from the Colorado Weed Management Association

  • Purple Loosestrife can produce 2-3 million seeds per plant per year.
  • Orange hawkweed produces hairy leaves that most animals will not eat.
  • Leafy Spurge contains sap that can blister the mouths of wildlife or cattle.
  • 75% of a Canada thistle plant is underground.

How are Noxious Weeds spread?

Seeds find their way into our eco-systems by hitchhiking on people, animals, water, wind or vehicles.

How are Noxious weeds controlled?

One or more of the following controls are prescribed based on weed type:

  1. Cultural control
  2. Mechanical control
  3. Biological control
  4. Chemical control

Where can I get a Noxious Weed management plan?

The Natural Resource Stewardship group provides the Integrated Weed Management Guide for parks staff, landowners and managers of lands with natural values.  Hard copies can be requested by e-mail

Colorado noxious weed law requires certain weeds to be eradicated, suppressed or contained.  For the full weed law and list, check out the Colorado Department of Agriculture’s Noxious Weed Program.

The Resource Stewardship group invites concerned Coloradoans to learn more about protecting Colorado’s best places by reading any of the many educational fliers available at Colorado State Parks.