I've never seen Johnson grass with such short seed stalks. Johnson cannot stand to be mowed at normal mowing height, so simple mowing will take it out. This looks like something else.

Thanks for the response dchall, here's another specimen that was growing quite tall up through a shrub.

Damned savages. I had to run a bead of roundup between my yard & the unmowed green space behind me. Helped a little.

Just wanted to follow up on this post I made a while back. I think I have a pretty solid ID on this. I believe it is brown top millet.