Lawn Weed Question

Annual bluegrass (Poa annua). LINK It will die in the heat of summer. You can try atrazine + surfactant by itself (not the cocktail mixture) but it likely won’t be that effective b/c of the maturity of those plants and some degree of herbicide resistance of Poa to the herbicide.

The key to “eliminating” it going forward is to to apply pre-emergent herbicide, like Prodiamine or Dimension (dithiopyr), in Fall (mid-Sept/mid-Oct).

Sir it appears like you have a lawn in your weeds

I've actually found mature Poa is pretty easy to pull up. I'd start by pulling up larger ones you can and then spraying at grade once that's complete. Spraying such mature poa like others have said won't do much good at this point.