Asian Copperleaf in Iowa

Asian Copperleaf is a relatively new weed in the state of Iowa. The first reported finding of Asian Copperleaf in the United States was 1990 in New York. The earliest discovery of this weed in the state of Iowa was Black Hawk County in 2016. Since that time, it has been identified in seven additional counties with recent identification in 2024 in Wright and Hardin Counties. Asian copperleaf is an annual plant that is small overall but can grow as tall as 24-30”. The leaves are lanceolate, serrated, with toothed leaf margins. The key identification of Asian copperleaf is the heart-shaped bracts that are located beneath the flowers of the plant. Asian copperleaf is tolerant of shade and can thrive in the sun. It emerges late in the season and can grow under the crop canopy through the growing season.

Asian Copperleaf is a member of the spurge family but does not have milky sap like other spurges. Virginia Copperleaf and three-seeded mercury are similar species that are found in the state of Iowa in woodland areas that are not disturbed and can be found near landscapes of homes. Virginia Copperleaf and three-seeded mercury are not typically found in fields that are row cropped.

Asian Copperleaf is a native of China, Australia and Japan. Research on Asian Copperleaf found in China found that Asian Copperleaf is resistant to HG 2 (bispyribac-sodium), HG 9 (glyphosate), HG 14 (PPO). Asian Copperleaf can be difficult to identify as a seedling such as waterhemp, velvetleaf and Asian copperleaf look similar at seedling emergence. Some diagnostic traits for waterhemp, velvetleaf, and Asian copperleaf include the following. Waterhemp has an egg-shaped cotyledon, a notched tip, no hairs on the leaf surface and lanceolate leaves with a waxy sheen. Velvetleaf has one heart shaped cotyledon, one round cotyledon, and is covered with soft hairs. In contrast Asian copperleaf leaves are lanceolate, serrated, two to three inches long, and the bracts are located beneath the flower and range from circular to heart shaped.

Please keep an eye out for this weed as you are scouting your fields this upcoming season. If you need help identifying a plant you believe could be Asian copperleaf, please contact your Iowa State Extension field agronomist for help and identification.