Dear Dantana, Thank you very much for your inquiry. The glyphosate will be effective on the Poa trivialis, despite its semi-dormancy state. Again, thanks for the question and let me know if you have more. Respectfully Trey Rogers, The Briggs & Stratton Yard Doctor, YardDoctor.com

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?

Read the directions on using it and follow them. You are limited in how much you can use in any year and it needs to be mixed precisely and applied to a certain amount of area in an even way. A hose end spray will not be precise enough. You will be filling up the pump sprayer a number of times to cover the whole yard. You might consider adding a dye as well as the surfactant so you can see where you've sprayed and where you haven't. Apply it after you aerate, not before, if you have to aerate. Poa annua ought to be pretty knocked out already by the summer heat. Applying Tenacity when you overseed in August will act as a pre-emergent for next year's crop of poa annua. Apply it again a month after seeding and then use a normal pre-emergent a month after that.

both. give it a try. just don't make the mistake when using tenacity that bleaching means its dead. it has to stay bleached for several weeks. itll shrivel up when it's dead.