Common Invasive Plants | Japanese Knotweed
Japanese Knotweed
Polygonum cuspidatum
Japanese Knotweed is a shrub-like, upright herbaceous perennial that grows to 10 feet. It spreads vigorously from long, stout rhizomes and forms dense stands. It also produces winged seeds that are carried to new areas. A significant threat to riparian areas.
How to Control
Herbicide application in Fall after flowers fade but before the first frost. The following Fall, a second herbicide application will be needed. Monitor for new sprouts in year three and treat as necessary. Cutting stimulates root/rhizome growth and is not recommended.
Help Us Map Japanese Knotweed
Visit The Newtown Knotweed Initiative to see how you can help.
Japanese Knotweed is a shrub-like, upright herbaceous perennial that grows to 10 feet. It spreads vigorously from long, stout rhizomes and forms dense stands. It also produces winged seeds that are carried to new areas. A significant threat to riparian areas.
How to Control
Herbicide application in Fall after flowers fade but before the first frost. The following Fall, a second herbicide application will be needed. Monitor for new sprouts in year three and treat as necessary. Cutting stimulates root/rhizome growth and is not recommended.
Help Us Map Japanese Knotweed
Visit The Newtown Knotweed Initiative to see how you can help.
