Thanks Hortsense. Here is what DLF says about Sabre III: SABRE III is the latest generation of improved Poa trivialis from DLF International Seeds' plant breeding program. It was developed to provide golf course superintendents who overseed with a denser and darker green turf. Sabre III has shown improved overall turf quality in comparison to older varieties. Other benefits of overseeding with Sabre III include rapid establishment and a good level of resistance to leaf spot. Sabre III was developed for elite, rapid to establish, easy transitioning winter overseeding turfgrass mixtures. It's also recommended for cool season, shade tolerant, mild climatic zones. It has excellent shade tolerance. -Dark green color -Quick establishment -Very fine texture -Good cold tolerance

Tenacity can help here, and it doesn't kill your (northern, which I assume it is) lawn. Although several sprays may be necessary to finally control it, and you do have to keep after it (it'll keep coming back for a number of years), eventually you do finally get rid of the stuff.

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?

Only a fraction of poa triv actually seeds. Usually the mature stuff. Most of it doesn't. The stuff that doesn't seed can be very fine bladed. To me, the immature stuff is tougher to kill as you can't easily apply roundup to it. That said, I think the immature stuff *might* be controlled by Tenacity.