These pictures were taken in Williamson County, TX, specifically Round Rock, but the weed is all over the place in Central Texas. I'm referring to the taller weeds in the pictures.
can't tell for sure, but it might be the wildflower Gay Feather.
It makes beautiful orchid-colored flower spikes in late summer or early fall.
It's wonderful in dry or xeric beds in the home landscape.
Looks like horsetail/mare's tail/hairy fleabane to me.
Here is a link that might be useful: hairy fleabane
Figured it out...it is baccharis neglecta, usually called roosevelt weed or poverty weed.