Land Plants - invasive

Japanese Knotweed (Fallopia japonica) on Oct 4, 2018

Submitter does not have a specimen
EDRR Status: Local expert notified

Description of specimen

Very large, alternate, heart-shaped leaves, stem with nodes like bamboo and purple spots, up to 10 or 12 feet high in spots, very small white flowers in a raceme. It is growing with a lot of Himalayan blackberry which is, of course, another invasive but that one is already widespread. (Sorry--no flower photos--I took these in June when I thought the city would help.)

Commentary

None

Remedy

Identify and manage knotweeds in the Pacific Northwest

Location

The Japanese knotweed is on both sides of Carman Drive. It is growing in an undeveloped drainage ditch/ roadside woods, between some houses and a large new business development. It starts just SW (the road is curvy) of the roundabout at Carman and Meadows, after the sidewalk and office buildings end. It has spread to the entrance to the new reservoir. I have reported it to the City of Lake Oswego twice. My neighbor has reported it for several years.

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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