Palmer amaranth (Amaranthus palmeri) is native to the desert regions of northern Mexico and the southwestern United States, and has spread into the Midwest, the East Coast and portions of Canada. Palmer amaranth is a relatively new introduction in Iowa, Minnesota, South Dakota, Wisconsin and the Northwest U.S. Palmer amaranth can be distributed by birds, though livestock feed, manure, grazing, wind, farm equipment etc. Amaranth expansion was accelerated in 2016 as an unintentional contaminant in some native seed mixes purchased by growers participating in conservation programs.
Pest Alert – Palmer Amaranth
A petiole longer than the leaf blade is the most reliable vegetative
trait to distinguish the two pigweeds. Not all leaves on a Palmer
amaranth will have this trait.
Photo credit Robert Hartzler, Iowa State University
