The plant was found in a field during a corn harvest in Stephenson County. It’s native to eastern Asia; the first U.S. detection was in 1990 in New York.
It spreads rapidly through seeds, which can move through landscapes via waterways. The University of Illinois Extension says there have been reports of herbicide resistance in its native ranges. It’s concerned the species could develop a similar resistance in the U.S.
Illinois is the third state with an Asian copperleaf presence. It’s already been found in 10 counties in central and western Iowa…