Hester Winterbourne wrote:Or a Persicaria of some sort, like Persicaria odorata. Although I wonder if Persicaria is a synonym for Polygonum...
I think it is synonymous. And yeah, I think it's some kind of knotweed. Mine has no odor at all.
I found this one, and it may be it, because it also has the light marking, in addition to the dark marking: