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:
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