Asian copperleaf, an emerging weed in the Midwest, has been confirmed in a second Illinois county, University of Illinois Extension reports. The new population in Carroll County follows the first Illinois find in Stephenson County during the 2025 harvest and suggests the weed may be more widespread than thought.

The species is not native to the United States. It was first documented in New York in 1990 but not confirmed again until it was identified in an Iowa seed corn field in 2016; it has since been found in twelve Iowa counties, two counties of northwest Illinois and southern Minnesota.

Autumn is the best time to identify it, because the plant is in its reproductive stage; it is often first noticed after harvest as a green "carpet" left when the crop comes off. Its leaves are alternate, lance- to egg-shaped with bluntly serrated edges and deep veins, and it carries a distinctive heart-shaped bract.

Extension says identifying and reporting populations is essential to stop seed moving to more fields, and asks farmers who suspect the weed to contact educator Kathryn Seebruck. A fact sheet from Illinois and Iowa State extension covers identification and management.

Photo: Dalgial / Wikimedia Commons (CC BY 3.0)

Source: Morning Ag Clips