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

Certainty is no longer labelled for cool season grasses. Compared with Velocity, it is inferior but both leave much to be desired on poa triv control. It may be worth it to try if you are at your wits end and need something to try before a nuclear option is entertained. I personally think early spring selective roundup is the best way. But for poa triv that is young and intermingled with the desirable grasses... no way you can selectively apply roundup. My current experiment is to hit it with Tenacity until it bleaches, then spray primo maxx and follow up with Tenacity. We'll see. I would also urge you to NOT irrigate in the heat of summer. Poa triv is the least heat tolerant of your CRF, PRG, KBG mix. Hopefully much will bow out. Also be on the look out for seeding. If you don't frequently mow or let it grow too long, it will seed and then you have not just stolon spread but a seedbank to contend with.

You guys aren't listening. Pre-m right now (spring) has nothing to do with controlling Poa annua. It is not germinating in spring. It is growing and flowering (seed production). Killing it now isn't going to help you either. Subywu, you cannot renovate those areas in fall and expect to have the upper hand. It is fall when Poa germinates. And yes, just like crabgrass, it will continue to germinate as long soil temps permit. Some people think crabgrass germinates when the forsythias bloom, which is March normally. But it continues to bloom through June. Then they wonder why they still have crabgrass in summer. Poa will not stop germinating either, and all the mechanical practices don't help, such as core aerating and power raking. They bring Poa seeds to the surface, exposing them to air and light. But, you want to be able to those things in the fall. That's another reason I said Poa control and renovation coincide. The favorable time to renovate your lawn is also the best time to battle Poa annua. In my last response in this thread, I let him know that after the grass seeds germinate and the lawn is established, he still has to kill any Poa that had a chance to grow. That effort is in late fall and could well mean December. Again..... Do not think pre-m will help you with Poa right now. It will only help you with crabgrass and other grassy weeds, but not Poa. Do not think you can pre-m in fall and that's all. It germinates throughout the fall growing season and as long as soil temps permit. When you're applying the last fertilizer for the season, you are also feeding Poa annua. Early season pre-m is not enough. Do not think the pre-m you used is effective. Find out just how effective it is. It will do you absolutely no good if it only prevents germination by 50 percent because come spring, Poa doesn't care. You still have to find a way to kill off new Poa later in the fall. This may be done with pre-m products like Halts or Dimension that also have some early post-m effectiveness. But again, you want to find out which one is most effective on Poa. Do not think battling Poa and renovating the lawn will be easy. It is not, and is often not effective because you are going to encourage Poa to germinate. You have to decide to do one and put off doing the other. If you do both, you still have to aggressively attack Poa later in the fall season without damaging your new grass. Here are many herbicide labels and their facts sheets.

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?