Foliage
Opposite leaves are joined at the base and form cups that surround the prickly stem.

Flowers
The small, white flowers densely cover oval flower heads and are present from July to September. Spiny bracts are located on the ends of flower stems.

Fruit
A single plant can produce up to 2,000 seeds and can remain viable in the soil for at least two years.

Ecological Threat
Dipsacus laciniatus grows in open, sunny habitats preferring roadsides and other disturbed areas, although it can sometimes be found in high-quality areas such as prairies, savannas, seeps, and sedge meadows. It was introduced from Europe in the 1700s and spreads by producing abundant seeds. It can be found in the northern states from Massachusetts to Colorado. This is an EDRR plant for the Southeastern United States. It has been reported in Virginia, West Virginia, and Kentucky.

Citations
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Southeast. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-05. Retrieved from http://bugwoodcloud.org/resource/pdf/FHTET-2017-05_New%20Invaders_SE.pdf

Winston, R.L., Andreas, J.E., Milan, J., DesCamp, W., Randell, C.B., and M. Schwarzländer. 2014. New Invaders of the Northwest. United States Department of Agriculture, Forest Health Technology Enterprise Team. FHTET-2014-12. Retrieved from https://www.fs.fed.us/foresthealth/technology/pdfs/FHTET-2014-12_NW_New_Invaders.pdf
 

Resources

• Vegetation Management Guide - Illinois Nature Preserves Commission

Selected Images

Maps

Invasive Listing Sources

• California Invasive Plant Council
• City of Ann Arbor Michigan Parks and Recreation
• Colorado Noxious Weeds
• Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
• Indiana Invasive Species Council - Invasive Plant List
• Indiana Terrestrial Plant Rule
• Invasive Plant Association of Wisconsin
• Invasive Plant Species of West Virginia
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
• Kentucky Exotic Pest Plant Council - Significant Threat
• Minnesota Noxious Weeds
• Missouri Noxious Weeds
• Missouri SRISP Species List
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• New Invaders of the Northwest
• New Invaders of the Southeast
• New Jersey Invasive Species Strike Team 2017 Invasive Species List
• New York Regulated and Prohibited Invasive Species - Prohibited
• Non-Native Invasive Plants of the City of Alexandria, Virginia
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ohio Invasive Species Council
• Oregon Noxious Weeds
• Pacific Northwest Exotic Pest Plant Council, 1998
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Invasive Species Strategic Plan and Volunteer Guidelines 2014
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References