Somehow I always thought of this plant as a bamboo. It grows quickly and features nodes that look an awful lot like bamboo.
Japanese Knotwood, Polygonum cuspidatum, was introduced to the US from Japan in 1890. It quickly established itself as an out of control pest. Well, that's the popular thinking any way. I like it! In fact, it is really best to appreciate it as eradication seems to work with nothing less than dynamite. Suggested removal techniques include mowing every few weeks for two years (if not that often its growth is actually encouraged!) or repeated herbicide treatments. Fire won't stop it.
Here we catch a glimpse of three-winged calyx enclosing a single seed.
I'm looking forward to spring when I will catch this tenacious beast sprouting and quickly shooting up.