Noxious Weed Management

Noxious weeds are aggressive plants that are not native to our area. Most have come from Europe or Asia either accidentally or as ornamentals that have escaped. These plants have

an advantage because the insects, diseases, and animals that would normally control them are not found here. Because these plants have developed specialized mechanisms to survive, they are able to spread at an alarming rate.


The Douglas County Board of County Commissioners adopted an Undesirable Plant Management Plan in accordance with the requirements of Colorado state law, Colorado Noxious Weed Act, §35-5.5-101-119, C.R.S. The County provides a complete listing of identified noxious weeds in the Undesirable Plant Management Plan.

Douglas County utilizes integrated weed management techniques to combat noxious weeds. These techniques include biological control, hand pulling, revegetation to include use of competing grass seed mixes and herbicides. The County program places strong emphasis on education. As part of our ongoing effort, the County provides informational flyers detailing biology and control measures for many of the noxious weeds on the undesirable plant management plan.


Douglas County Noxious Weed Plan and Enforcement Resolution

Noxious Weeds and Our Natural Areas

Noxious weeds are moving into our valued ecosystems and displacing our native plants at an alarming rate. When the plants that wildlife uses for food, shelter, or nesting are gone, the wildlife leave the area.

Noxious Weeds and Our Agricultural Lands

Noxious weeds also impact our valuable agricultural lands and commodities. When resources are not available for their desired use, it takes more land to raise the same number of cattle or bushels of wheat.
Because of these factors, they have been declared by state, local, and federal governments to be undesirable, and their control, containment, and eradication are required by law.  In Douglas County the following weed priorities have been made for eradication A-list:

  • Purple loosestrife (Lythrum salicaria)
  • Orange hawkweed (Hieracium aurantiacum)
  • Yellow starthistle (Centaurea solstitialis)
  • Myrtle spurge (Euphorbia myrsinites)
  • Dyer’s woad (Isatis tinctoria)
  • Mediterranean sage (Salvia aethiopis)
  • Medusahead (Taeniatherum caput-medusae)
  • Rush skeletonweed (Chondrilla juncea)
  • Squarrose knapweed (Centaurea virgata)
  • Meadow knapweed (Centaurea pratensis)
  • Camelthorn (Alhagipseudalhagi)
  • Common crupina (Crupina vulgaris)
  • African rue (Peganum harmala)
  • Cypress spurge (Euphorbia cyparissias)
  • Sericea lespedeza (Lespedeza cuneata)
  • Tansy ragwort (Senecio jacobaea)
  • Hydrilla (Hydrilla verticillata)
  • Giant salvinia (Salvinia molesta)
  • Elongated mustard (Brassica elongate) 
  • Giant reed (Arundo donax)
  • Hairy willow-herb (Epilobium hirsutum)
  • Japanese knotweed (Polygonum cuspidatum)
  • Giant knotweed (Polygonum sachalinense)
  • Bohemian knotweed (Polygonium x bohemicum)

B-list weeds to be eradicated when found are:

  • Spotted knapweed (Centaurea maculosa)
  • Russian knapweed (Acroptilon repens)
  • Salt cedar (Tamarix chinensis, T.parviflora, and T. ramosissima)
  • Plumeless thistle (Carduus acanthoides)
  • Bull thistle (Cirsium vulgare)
  • Perennial pepperweed (Lepidium latifolium)
  • Hoary cress (Cardaria draba)
  • Houndstongu Cynoglossum officinale)
  • Chinese clematis (Clematis orientails)
  • Absinth wormwood (Artemisia absinthium)
  • Black henbane (Hyoscyamus niger)
  • Bouncingbet (Saponaria officinalis)
  • Common tansy (Tanacetum vulgare)
  • Common teasel (Dipsacus fullonum)
  • Corn chamomile (Anthemis arvensis)
  • Cutleaf teasel (Dipsacus laciniatus)
  • Dame’s rocket (Hesperis matronalis)
  • Eurasian watermilfoil (Myriophyllum spicatum)
  • Mayweed chamomile (Anthemis cotula)
  • Moth mullein (Verbascum blattaria)
  • Oxeye daisy (Chrysanthemum leucanthemum)
  • Scentless chamomile (Matricaria perforata)
  • Sulfur cinquefoil (Potentilla recta)
  • Wild caraway (Carum carvi)

B-list weeds to be contained when found are:

  • Dalmatian toadflax (Linaria dalmatica, L. genistifolia)
  • Scotch thistle (Onopordum acanthium, O. tauricum)
  • Musk thistle (Carduus nutans)
  • Diffuse knapweed (Centauria diffusa)
  • Yellow toadflax (Linaria vulgaris)
  • Leafy spurge (Euphobia esula)
  • Canada thistle (Cirsium arvense)
  • Russian-olive (Elaeagnus angustifolia)
  • Yellow nutsedge (Cyperus esculentus)

The remaining B-list weeds are to be monitored and suppressed as funds are available:

  • Absinth wormwood (Artemisia absinthium)
  • Black henbane (Hyoscyamus niger)
  • Bouncingbet (Saponaria officinalis)
  • Common tansy (Tanacetum vulgare)
  • Common teasel (Dipsacus fullonum)
  • Corn chamomile (Anthemis arvensis)
  • Cutleaf teasel (Dipsacus laciniatus)
  • Dame’s rocket (Hesperis matronalis)
  • Eurasian watermilfoil (Myriophyllum spicatum)
  • Mayweed chamomile (Anthemis cotula)
  • Moth mullein (Verbascum blattaria)
  • Oxeye daisy (Chrysanthemum leucanthemum)
  • Quackgrass (Elytrigia repens)
  • Redstem filaree (Erodium cicutarium)
  • Russian-olive (Elaeagnus angustifolia)
  • Scentless chamomile (Matricaria perforata)
  • Spurred anoda (Anoda cristata)
  • Sulfur cinquefoil (Potentilla recta)
  • Venice mallow (Hibiscus trionum)
  • Wild caraway (Carum carvi)
  • Yellow nutsedge (Cyperus esculentus)