Land Plants - invasive

Japanese Knotweed (Fallopia japonica) on May 19, 2025

Submitter has sample
EDRR Status: Local expert notified

Description of specimen

The Japanese knotweed has gotten worse every year and has been taking over more of the fence-line. I am worried it will kill my arborvitae by choking it out. They are about 20 feet tall already.

Commentary

None

Remedy

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

I live in a house on the corner of chalet and sleepy hollow in rural Sandy, Oregon. Along my fence on Sleepyhollow there is a creek that runs behind our house. The Japanese knotweed is running along the fence and taking over my arborvitae

Expert Reviewer

Samuel Leininger
Clackamas Soil and Water Conservation District
4-County Cooperative Weed Management Area
Columbia Gorge Cooperative Weed Management Area

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