Japanese Knotweed (Fallopia japonica) on May 22, 2010
Submitter has sample EDRR Status: Local expert notified
Description of specimen
A group of about 20 to 25 plants have been spreading over last 5 years or so.
Commentary
Would like to know best way to control/eliminate
Reporter
May 22, 2010, 3:21 a.m.
Thanks for the report, Ed. You have some options, but we've been finding that herbicide applied to leaves in Sept/Oct has been very effective; summer stem injection also seems to have potential. Fortunately, there are a handful of organizations who would be able to treat that patch, given permission from the property owner. Let's talk directly about arranging that, whether it's your property or a neighbor's, and think about treatment later this summer. Meanwhile, it's okay to let grow out.
Oregon State University's Solve Pest Problems page has some great information about how to get rid of knotweeds Solve Pest Problems
This is a tricky weed to manage. Consider reaching out to your local Soil & Water Conservation District for technical advice.
Location
Side hill next to house. Area has no standing water but is wet all winter with small springs further downhill in heavy rains. Area has not been cultivated except for original house construction about 25 years ago.
Expert Reviewer
Mr. Mitch Bixby City of Portland - Bureau of Environmental Services (BES)
Reporter
May 22, 2010, 3:21 a.m.
Looking forward to talking with you.
-Mitch
mitch.bixby@portlandoregon.gov
Mitch Bixby
May 25, 2010, 3:35 a.m.