Land Plants - invasive

Knotweed (unknown species) (Fallopia sp.) on Jul 7, 2020

Submitter has sample
EDRR Status: Local expert notified

Description of specimen

I have tried to dig it up but the bright orange roots are so invasive I would need to excavate down 3-4 feet to eradicate them. I tried clipping the stem and shooting Roundup down the stem. It has made a small inpact on the plants in my upper area but the slope will be impossible to get to because it is steep. It is spreading quickly and I do not think my neighbor understands what is happening, nor am I sure they would care!. I thought I could dig them all up but it does not seem possible. Can we get some outside help on this? I will also contact the Clackamas County soil conservation district.
Thanks in advance for any help/suggestions you can provide.

Commentary

None

Remedy

Knotweed Shrub Complex: Identification, Biology, and Management, Oregon Extension Service

Location

On an east facing slope in my front yard that goes down to a creek that divides my property from the neighbors. We are on Borland road in Stafford. On my side it is confined to the slope and it has crept up onto my yard in one area. I first saw it last year. This spring it went wild, spreading down the slope. Now it has jumped the creek and is on the neighbors bank side. It has also spread rapidly up the hill along the creek to the north.
This year I took the Online Master Gardeners class and was able to identify it last week in the noxious weeds webinar. This infestation is huge and growing quickly.

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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