Have a pigweed? Do you believe it may be waterhemp or Palmer amaranth? Watch this pigweed identification video to learn how to identify and report them!
Pigweeds include many species of the genus Amaranthus that grow as annual summertime weeds. The goal of this project is to identify the location of two extremely problematic pigweeds – Palmer amaranth (fact sheet) and waterhemp (fact sheet). These two species have developed resistance to commonly used herbicides in agronomic settings in Wisconsin, making it difficult for farmers to control their spread.
You! We need everyone’s help to report locations of these two super pigweeds in Wisconsin. While we are focused on agricultural fields, we still want positive identifications of either waterhemp or Palmer amaranth from any habitat.
Tracking the location in Wisconsin of these pigweeds is vital to efforts to stop the spread of these problematic pigweeds across our natural and agricultural landscapes. These weeds are like super-weeds, being able to disperse more seeds, wait later to emerge, and have higher growth rates than most other pigweeds. This results in lower crop yields and the use of more chemicals in agricultural fields. More information on herbicide resistance in pigweeds is coming soon.
Everywhere! You can look anywhere for these pigweeds. Currently, the biggest concern is in agricultural settings, but Palmer amaranth and waterhemp also grow along roadsides and in gardens, among other habitats.
Palmer amaranth and waterhemp are summer annuals, so it will be easiest to identify and report these species starting in the summer.
The ?’s (and Answers!) on Reporting a Pigweed
If you believe you have Palmer amaranth or waterhemp, please report it. Your reports help track these pigweeds in Wisconsin and improve efforts to limit their spread. There are a few ways to report a pigweed:
We recommend using the Great Lakes Early Detection Network (GLEDN) app. Go to the Google Play (Android users) or the App Store (Apple/iOS users) and download the GLEDN app. Find more information about reporting with the GLEDN app here.
If you do not wish to download the GLEDN app, you can report your pigweed by emailing us at email@example.com and include these pieces of information:
1) Location of the pigweed: GPS coordinates (in decimal degrees; NAD83 or WGS84) or an address/road intersection
One way to find GPS coordinates is to visit Google Maps. Right click on the location of the plant(s) and select “What’s Here?”. A gray marker will appear and the coordinates (in decimal degrees) will be displayed at the bottom of the screen.
To report an address/road intersection, please include an additional description. For example, “100 feet southwest of the intersection of County Rd DL and Hwy 113 in Merrimac” or “200 feet east of 1151 Observatory Drive in Madison.”
2) The habitat where the pigweed is growing: agricultural field (indicate what type of field, e.g. corn, soybean, etc.), home garden, roadside, or other (please describe).
3) Indicate whether the plant may be herbicide resistant, and if so, what herbicide has been applied.
4) Pictures of the pigweed, including a picture of the whole plant, a picture of the plant stem, and a picture of the leaf and petiole (leaf stem).