Noticed this in the last two years, and this year seeing small examples in places I never had trouble before.

very light stringy tri-foliate vine "floats" over other plants (in the pic over some sort of grass -- which I'd also love to id). Roots tightly but easy to tear away, less so if you actually want the root. More mature examples have almost woody stalks and some sort of (maybe) shoot/runner.

Found a flower stalk today: purple flowers on a fairly long stalk (10-12"?), very sparse but maybe I was late to catch the seeding. and the flowers have already dried and fallen off.

Since it floats, earlier this season I weedwhacked the floaters (I also just walk through the patch kicking the vines).

Today, when I was pulling ZTA (zero tolerance area) those whacked stalks were still alive but no new growth that I could spot.

can anybody ID?
Have an idea on when seeds mature?

thanks folks!