There are some people out there that are having success with Tenacity. Ethofumasate (Prograss) is a selective herbicide that targets poa annua. Velocity is another one, but that one might be restricted to professionals only, and it can cause temporary harm to KBG. A good anti-poa annua strategy involves regular preemergent applications, especially in late summer, and late winter/early spring. Controlled round-up application will obviously kill poa annua, but if you don't have a spreading grass like KBG, those areas will remain bare, but you can always plant some grass in pots to fill in the bare areas since you will have a preemergent barrier down.

The mowing shorter recommendation goes against everything I've done up until this year. I was a great fan of leaving the height grow to 4", then mowing it down to three. Then, last fall, the Magnificent Twenty of us put in these premium cultivars for new lawns (Mag 3 mix, more or less, for most of us, but modified a cultivar here, a cultivar there), and we (and the original poster) now have 'dwarf' species, or 'compact' species of bluegrass, starting with Midnight or Midnight II. I fear that 'compact' or 'dwarf' means 'short', at least in the short term (first full year of establishment). What the OP needs at present is a way to get the new grass spreading out, even if it's at the cost of somehow 'less than optimal' if optimal means more height, more roots, but less spreading this year. I believe a thread here in the forum supports this strategy. Everybody seems to be encountering (in April) a low-growth habit, and a need of fertilizer. We know that KBG is a 'heavy feeder', requires more fert than other lawns. We know that new KBG lawns require even more fert than that, although some of us aren't going to put it down that heavily. We should. That new KBG is coming in pretty low to the ground. Lower than we are used to. I think the literature will support the proposition that the new lawn should be mowed shorter than we would have mowed our old KBG lawns, last year, if what we want this year is maximum 'spreading' as opposed to maximum 'taller'. No question the poa can survive. It will be there til the heat of summer. But the dose of pre-M in summer, followed by another dose of pre-M in the fall, should go far toward seeing that those poa seeds don't germinate this fall (and I think that most of us know that poa germinates in the fall, not in the spring). At that point, what's left on that lawn? With luck, brand new KBG, at the end of its first full season. With maximum spreading. Since there isn't going to be much spreading in the heat of July and August, that's got to be done this spring, when that grass stand is immature. Which prompted the somewhat counter-intuitive advice to mow it shorter than usual, this first full season. I do believe that all of us, in the Magnificent Twenty are going to end up mowing shorter than we're used to, say, up to the 4th of July. We'll have to wait until the reports come in, to see if that's the case. But the Original Poster can't kill poa now, he's got to wait til fall, and kill the seeds, with the pre-emergent. And he's got to have a pretty well spread out stand of new KBG there, when the poa goes away.

Poa grass should be re-named devil grass. My entire back yard is all poa.Two years ago, it was maybe 25%. We Dug, Pulled, Used round up when the bermuda was dormant, and have tried everything. This year it is impossible. It has been too cold here in Jackson,tn. to make this stuff die. We have just given up. When you are spending so much on your lawn and this stuff just grows and grows it is a big waste of money. Is there any thing that will eliminate this stuff? and where did it come from?

Despite what I'm being told I am pretty much giving up hope that all these seed heads are coming from my turfgrass. I've been researching poa annua a little bit more and images I see online look very much like what I have going on in my lawn. Here are a few more pictures of my lawn... Opinions? If it is poa annua (I'm convinced that it is), I can't for the life of me figure out why this is happening. My lawn was started from seed in September 2013. I didn't have any poa annua problems in 2014 (nor any of these seed heads). I mow high and I water infrequently. And the kicker is I see nothing like this in any of my neighbors lawns, none of whom take lawncare seriously...so why would it take hold in my thick, high lawn but not in theirs? Was it mixed into the seed the landscaper used but didn't take hold until now? I overseeded last Sept but I know it wasn't in that seed because I had a few bare spots I fixed and those spots are free of these seed heads. And what do I do about it? Kill everything and restart? Keep spraying Tenacity in hopes I beat it? Or, since it's an annual, will it all die this summer, then use preemergents more aggressively?