Knotweed (unknown species) (Fallopia sp.) on Aug 25, 2010
Originally reported as Japanese Knotweed (Fallopia japonica)
Submitter has sample
EDRR Status: Local expert notified
Description of specimen
I found four separate clusters of Knotweed growing. The first cluster is on the Metro River Island Greenspace property in a clay bank across the river from where the River Island Sand And Gravel pump was removed from the river last week. The second, third and fourth clusters are on private property belonging to my Father-in-law, Harry Gerber. Several years ago a team of workers from the county or possibly Metro treated the clusters and they felt they were successful in killing the Knotweed. The address of the propeerty is 22100 S. Claus Ct., Oregon City, OR 97045
Commentary
Expert Reviewer
Samuel Leininger
Clackamas Soil and Water Conservation District
4-County Cooperative Weed Management Area
Columbia Gorge Cooperative Weed Management Area
Thanks for reporting this infestation of knotweed. Knotweed is a significant problem invader, particularly in riparian communities within Clackamas County. The Clackamas Soil and Water Conservation District is working with regional partners to map and catalog known infestations of knotweed to help prioritize future control efforts.
I have forwarded your report to land managers with Metro, and they are aware of the problem. They are currently managing weeds on thier property and will use your report to prioritize treatments on thier property.
I also appreciate the report of the three patches on your Father-inlaws property. Unfortunately, the resources needed to control this invader are limited in relation to the overall need. As such we currently offer technical information to local landowners to help them develop a management strategy that is effective to their particular site conditions and needs, but we are currently not able to treat knotweed on private land. If your Father-in-law would like assistance to control this population please feel free to have him contact the Conservation District.
Also please check these online resources to better manage knotweed on your property.
http://www.skamaniacounty.org/Noxious_Weeds/TNCreport.htm
http://www.imapinvasives.org/GIST/ESA/esapages/documnts/polycus.pdf
When working with knotweed it is important to avoid spreading root and stem fragments into streams and rivers. These fragments will float downstream to grow and develop into new knotweed plants.
If you are planning to use chemical control methods avoid drift into streams and adjacent native vegetation. Also be sure to read and follow the label. The label is the law. So be sure you follow all label directions, recommendations, and restrictions.
Again thank you for reporting this invader. Feel free to contact me if you have additional questions.
Sincerely,
______________________________________
Samuel Leininger
WeedWise Program Manager
Clackamas Soil & Water Conservation District
221 Molalla Ave. Suite 102
Oregon City, OR 97045
503-655-3144 x118
samuel.leininger@or.nacdnet.net
www.conservationdistrict.org
______________________________________
Samuel Leininger
Aug. 26, 2010, 9:48 a.m.