QuarterQuad Maps

Below are maps that depict the statewide distribution and abundance of selected noxious weed species in Colorado.

Data is requested from the County Weed Supervisors on an annual basis (no mapping was done in 2003) and infested acreages estimates are per 9,000 acre QuarterQuad. A QuarterQuad is one quarter of a standard 1:24,000 U.S.G.S. 7.5min topographic quadrangle.

Each block of color represents an infested 9,000 acre area: lighter red blocks indicate the presence of relatively light or new infestations, while darker red blocks indicate the presence of a greater number of infested acres within the QuarterQuad. Counties that have not reported their weed infestations are indicated with a cross-hatch pattern.

For more specific locations of noxious weeds, you should contact the appropriate County Weed Manager .

Common Names Scientific Names Data Year
Absinth Wormwood Artemisia absinthium 2004
African rue Peganum harmala 2008
Black henbane Hyoscyamus niger 2005
Bull thistle Cirsium vulgare 2009
Chinese clematis Clematis orientalis 2004
Cypress spurge Euphorbia cyparissias 2006
Dalmatian toadflax Linaria dalmatica 2007
Dame's rocket Hesperis matronalis 2002
Diffuse knapweed Centaurea diffusa 2005
Dyer's woad Isatis tinctoria 2008
Eurasian watermilfoil Myriophyllum spicatum 2009
Hoary cress Cardaria draba 2008
Houndstongue Cynoglossum officinale 2006
Leafy spurge Euphorbia esula 2007
Meadow knapweed Centaurea pratensis 2008
Mediterranean sage Salvia aethiopis 2008
Musk thistle Carduus natans 2009
Myrtle spurge Euphorbia myrsinites 2008
Orange hawkweed Hieracium auranticaum 2008
Oxeye daisy Chrysantheum leucanthemum  2005
Perennial pepperweed Lepidium latifolium 2006
Plumeless thistle Carduus acanthoides 2004
Purple loosestrife Lythrum salicaria 2008
Russian knapweed Acroptilon repens 2008
Russian olive Elaeagnus angustifolia 2002
Saltcedar (Tamarix) Tamarix parviflora  2004
Scentless chamomile Matricaria perforata 2009
Scotch thistle Onopordum acanthium  2009
Spotted knapweed Centaurea maculosa 2004
Spurred anoda Anoda cristata 2007
Sulfur cinquefoil Potentilla recta 2008
Venice mallow Hibiscus trionum 2007
Yellow starthistle Centaurea solstitialis 2008
Yellow toadflax Linaria vulgaris 2005

Additional Weeds Mapped By QuarterQuad:

The maps below do not depict the statewide distribution and abundance of these eight weed species. Although the Colorado Department of Agriculture has not yet requested statewide data for these particular species, some county weed managers have volunteered this data and we have assembled the information here. These maps will continue to be updated as local jurisdictions provide additional data. If and when the Department endeavors to gather statewide data for these species, these maps will be moved to the list above.

Common Names Scientific Data Year
Canada thistle Cirsium arvense 2002
Cheatgrass Bromus tectorum 2002
Field bindweed Convolvulus arvensis 2002
Jointed goatgrass Aegilops cylindrica 2002

Researchers and data junkies may download our QuarterQuad datasets from the list below: