Land Plants - invasive

Japanese Knotweed (Fallopia japonica) on Jul 19, 2021

Submitter has sample
EDRR Status: Local expert notified

Description of specimen

See attached photo


First, this is a confirmed invasive knotweed plant. There are not currently any resources to help homeowners with control of knotweed besides technical advice. The very limited financial resources for knotweed are focused on populations along the Willamette River and tributaries. When knotweed is cut, it needs to be thrown in the garbage rather than compost due to it's amazing ability to sprout. It's highly likely that it will still grow back. Any fragment of the plant stem that is left on the ground has the ability to sprout, so a thorough cleanup is necessary. All this leads most managers to treat with herbicide rather than manual/mechanical control. You might contact a landscaper or vegetation contractor to assist in treating the weeds with herbicide. Thanks for this report.

Michael Ahr
July 20, 2021, 5:22 a.m.