Kent, Thanks for the report. This is indeed knotweed. It is extremely hard to achieve long-term control, but there are techniques, many of which you can find on this website under other Knotweed reports. I almost re-posted a set of control methods, but then I noticed that the location you reported is on State of Oregon land. As a reminder, only the land manager of that property can perform active noxious weed control. If the location is correct, I will pass on to staff at Tillamook State Forest who have been battling knotweed for years.

Thanks again for your report.

Wyatt Williams
Oregon Dept. of Forestry

Wyatt Williams
May 9, 2016, 7:37 a.m.