Knotweed

Knotweed on an American football field

Knotweed: Polygonum aviculare

Knotweed sap runs clear when stem is broken

Knotweed flowers are very small and inconspicuous

Common Names: Knotweed (English), Alambrillo, Asa Al Rae'Y, Bian zhu (Chinese), Bistorte aviculare (Italian), Box Knotweed, Centinodia, Correguela (Spanish), Gewoon Varkensgras, Habbat Al Rae'Y, Hemero Tea, Knotgrass (English), Kus Karabugdayi, Michi yanagi (Japanese), Nana Shwana, Niwayanagi, Pien Hsu, Prairie Knotweed, Prostrate Knotweed, Rdest ptasi (Polish), Renouee des oiseaux (French), Sea knotgrass, Small leaved knotgrass, T'Ieh Sien Ts'Ao, Varkensgras (Dutch), Vogelknoterich (German), Yard Knotweed

Geographic Distribution: North America, Africa, Europe, East Asia, Australia, South America

Major Identifying Characteristic: Oblong to linear blue-green leaves are alternately arranged. Sap runs clear when stem is broken.