when left to their own devices, lawn weeds will overthrow the world

All summer long, I’ve been idly observing a random lawn weed here at home, but I haven’t had any luck in keying it out. It’s a short guy with a raceme of teensy pink buds. As near as I could tell, those suckers were never going to open, I was never going to get a petal count, and its identity would remain a mystery.
Well, today, for the first time, I went for a run in the woods near where I work, and on the way back, I swung by for a closer look at the mess of stuff growing along a stream that runs through the industrial campus. (Yep, here in Vermont, we have woods and trails and streams in our industrial parks. Why would you want to live anywhere else?)
When I took a closer look at this stuff – a thicket of three and a half foot tall things…

…I about jumped out of my skin.

It’s my random lawn weed! In fact, it appears to be two versions of it: the darker pink kind with the reddish stem (drooping down, above), and the pale pink kind with somewhat larger flower buds.
So I ran inside to get my camera, and my coworkers thought, judging from the way I was bouncing up and down, that I’d experienced something really exciting, like maybe running into a bear or something. I said, “I DID! I FOUND OUT WHAT THIS LITTLE LAWN WEED IS WHEN YOU LET IT GROW!” …and they all moved away from me on the bench there...They don’t know about my little nature girl gig, see.

Some of those teensy flowers were open and tonight, with the help of my trusty Newcomb’s, I finally nailed this down as a knotweed, in the buckwheat family. Gotcha!
I also got one of my best pregnant jewelweed shots yet:

(If you’re new here, you might have missed my various odes to jewelweed. All the jewelweed you can handle, right here, or here, or even here. Go on, check it out, we’ll still be here when you get back.)
Finally, we have some exploded thistle.

Mmmmmm.