(Alternanthera philoxeroides)
Alligatorweed is native to South America and likely introduced through ships’ ballast water. First introduced to South Carolina in 1885, it has now spread across much of the South. It can reproduce from seed as well as vegetatively, rooting at the stem nodes or from plant fragments. Machinery, such as mowers, boat motors, etc. can easily distribute this plant across large areas and establish new populations.