# (what I believe is) annual bluegrass is current nemisis



## x78240 (Jun 15, 2020)

Good morning everyone,

I have been having the struggles with getting a main section of my lawn to grow after seeding. I seeded last spring and the crab grass eventually took it over. So I started over (by seeding again) in the fall after aerating, had the TTTF coming up fairly well, and cut and fertilized a few times before winter.

Now I have a huge problem with (what I believe) is annual bluegrass, seen below. It looks like the pictures of annual bluegrass I've seen and meets the characteristics (bunched root, lighter cooler, seeds). I've read a lot online how to make sure it doesn't live (infrequent heavy watering, having a fully established yard, etc.). But what should I do right now? I'm in zone 7b, I'm about to start seeding some bare spots I have in other sections of the yard, but I can't exactly overseed this area, the annual bluegrass is so thick.

I've read this weed often dies in the heat of summer, but it going to leave a HUGE bald spot once it dies. Therefore, should I kill the whole section now (tarp over it, round up, ?)and reseed in a few weeks? Should I try to pull as much of it by hand as possible and seed in the spots I pull it? Should I try tenacity on it right now and try to reseed in a few weeks?

Just getting frustrated because weeds are just killing any gains I makes. I can't really lay down a pre-emergent since I'm trying to seed. I'm at the point when I'm going to spend the 4-5 hours ripping up each stalk of this week and then reseeding each individual bare spot, but I thought I would check with y'all to see if there's something you would recommend.

Any help or thoughts would be very helpful. Thanks!


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## Powhatan (Dec 15, 2017)

It's poa annua. A fall preM when soil temps lower to 70F is the preventative for future.

The area in the pic has a lot of poa a. I'm not sure what a good course of action would be for what you have now so I'll let someone else chime in on that.


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## ScottW (Sep 16, 2019)

Yes that's Poa annua.
They drop seed in spring, survive or die in summer depending on heat & rain/irrigation, and the seeds germinate in fall.
The best way to break this cycle is with fall applications of pre-emergent (prodiamine).

Now in your situation, whether you tarp it or use glypho to kill it, the level of infestation tells me there's still going to be a crap-ton of its seeds in your soil. Years' worth. Regardless of what you do in the short term, this will happen again next spring if you don't do a fall pre-em.

Spring seeding TTTF can be successful especially if this area gets some shade in the summer.
At this point though, your options all suck at least on some level.
Tarping or glypho'ing it will leave a lot of dead stuff with only marginally more exposed soil for your new seed. Therefore I would say pulling the Poa is the better solution, but obviously it's a ton of work up front. The good news is that it pulls pretty easily if the soil is wet (gonna rain today) and you grab down low near the center of the clump. That will expose plenty of bare soil for dropping your new seed. In order to minimize the crabgrass threat you can do a blanket app of Tenacity right over the top of your seeded TTTF. If you're going to do this, you'll want to move on it pretty soon because summer will arrive to threaten your new seedlings before you know it, and we're already late in the game for crabgrass germination. You might want to prepare by stocking up on selective post-emergent herbicides, because some will pop up this summer. Crabgrass is also easy to hand-pull, depending how much you've got.

If the spring seed comes in fine, you can just go out with the prodiamine in the fall instead of seeding more TTTF then.
If this is a full-sun area then spring seeding gets more dubious. If the spring seed doesn't come in well and survive the summer you'll be wanting to seed more TTTF in the fall. In that case you're looking at multiple apps of Tenacity and/or ethofumesate for your fall pre-em duties, but they are not as effective compared to prodiamine.

Considering the level of infestation and the amount of work it's going to take to get under control, perhaps the best option, and I almost hate to say this, would be to stroke a check and have a landscaping company cut all that shit out and install new sod. With 1/4 acre (or less depending on the infested area?) the cost might be worth it to you. I'm as masochistic as anyone when it comes to lawn work, but I would consider it. It would also eliminate the threat of spring rains washing away your new seed given that this area appears to be on a significant slope. Then you just have to mow & water it, and you can roll out the prodiamine in the fall.


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## x78240 (Jun 15, 2020)

I appreciate the awesome insight. After I made the post this morning, I went outside to begin to arduous task of pulling it before the rain started.

Your thoughts are pretty much in line with what I was thinking: if I can get the seeds to "stick" in the spring, I can focus on prodiamine in the fall to avoid this next year.

If I can't get them to stick, I don't know what I'm going to do, except I did start looking up costs for getting some sod for that area around the slope in particular.

Also, I thinking I'm going to try to do what you recommended about getting tenacity down on all these bare spots I'm going to have when i go to seed. Thanks!!


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## ScottW (Sep 16, 2019)

Sounds like a plan.

Seeding slopes can be tough. Avoid any temptation to use straw as a cover to hold the seed in place. Straw contains weed seeds. There are products like Pennmulch that are basically compressed paper pellets that you spread on top of your seed that will then break up when you water them and expand into a pulp-like layer that does okay at holding the seed in place. However, that stuff isn't ultra cheap. Sod costs more, but if you've already got bare soil most of the manual labor has been done.

On the Tenacity, just to be clear...
First get your new seed down and raked/rolled/garden-weaseled into the bare soil, then get any top cover down for those slopes, then give that a light watering in. The next day you can spray the Tenacity over the top of all that. It's basically the last step of the overseed process. The idea is you have a layer of it sitting on top, so any weed seeds that blow into your yard, or any that sprout up from the ground you've disturbed while pulling that Poa and spreading your new seed, will contact the Tenacity layer.


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## x78240 (Jun 15, 2020)

Ok, I think I got it. I plan to use peat moss on top of the seed, so I should spray tenacity on top of the peat moss I suppose, the day after seeding.


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## VALawnNoob (Jun 9, 2020)

u should be able to spray tenacity same day as well. i have used the pennmulch thingy. it did work - kinda. in future i will stick w/ peat moss just to save the $. pennmulch value is a bit expensive for what you get - it is also a bit unsightly as it decompose.


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## x78240 (Jun 15, 2020)

yeah that mulch that sucks up water seems rather expensive. I'll probably just stick with peat moss.


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## Old Hickory (Aug 19, 2019)

So here is a question I've not seen: how many days after seeding (and before germination) can Tenacity be used? I know this depends on the seed as PRG is the fastest to germinate and KBG is the slowest (in general).


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