ADVERTISEMENT State verifies grass discovered on U.S. 49 an invasive species by The Arkansas Democrat-Gazette | Today at 1:44 a.m. The presence in Arkansas of cogongrass, an invasive species native to Southeast Asia, has been confirmed, according to the state Department of Agriculture. The department said in a news release that Charles Bryson, a retired botanist with the U.S. Department of Agriculture, spotted cogongrass, or Imperata cylindrica, in Helena-West Helena along U.S. 49. Bryson's discovery prompted officials with the Agriculture Department, the Arkansas Natural Heritage Commission and the Arkansas Department of Transportation to spray the area with herbicide. A survey of the immediate area detected no other cogongrass populations.