Report a Pigweed

photo of a pigweedThirty-five Master Gardener volunteers in Fond du Lac County and 40 Master Gardener volunteers in Dodge County learned about being first detectors for two species of pigweed (weeds in the Amaranthus genra) that are or may become problems in agricultural fields or in urban areas. Weed scientists with the University of Wisconsin-Madison want to document the locations of these weeds around the state so control measures can be implemented to help prevent their spread.

One of these problem pigweeds is called common waterhemp, and it HAS been found in Fond du Lac and Dodge Counties (see photo).  At these monthly meetings, Dr. Loretta Ortiz-Ribbing asked Master Gardener volunteers to look out for and report if they find waterhemp.  In addition, Palmer amaranth which has NOT been found in Fond du Lac or Dodge County yet but has been found in Waushara, Dane, Sauk, Rock, Iowa, and Grant counties, was described.  Both weeds are herbicide resistant and difficult to control but Palmer amaranth is even more of a concern than waterhemp and the desire is to keep it from getting established.

Master Gardeners or anyone suspecting they have found waterhemp or Palmer amaranth in their field, yard, or garden should go to to report a Pigweed.  This site also provides a video created by Dr. Mark Renz that provides an easy method for identifying if the pigweed might be common waterhemp or Palmer amaranth.  If you suspect that the plant is Palmer amaranth, Dr. Loretta Ortiz-Ribbing also wants you to contact her at

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