# Need advice on Poa Infested Tall Fescue



## Ortho-Doc (Feb 3, 2019)

My lawn has 5,000 sqft of beautiful palisades zoysia and 4,000 sqft of frustrating y'all fescue. My lot slopes from front to back and ends where the fescue sits in moderate shade beneath tall trees. I put fescue in this area due to low sunlight conditions but each year the poa ends up eating my lunch by April. I slit seeded last year and got beautiful germination only to get crazy rainfall that took out large portions of the baby fescue. I just can't seem to get the fescue to thrive in this shady wet area.

I'm about done stressing over this fescue but don't know what to do with this 4,000 sqft of fescue. It kills me that I've got this eye sore amidst the rest of my highly manicured property. What to do folks? Take a shot with a shade tolerant zoysia? If so, after I kill the fescue how do I slope the ground to make sure the water runs off at the end of my lot? Alternatively, should I mulch it all in and create a "naturalized area" as a landscaper recommended? I'd appreciate any and all opinions.


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## Ortho-Doc (Feb 3, 2019)

Selfish 'bump'. Need some help from this forum of fellow lawn fanatics.


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## g-man (Jun 15, 2017)

I saw this yesterday, but I've been busy with installing xps insulation to the rim joist.

I have a couple of ideas and some are crazy. Let's start with the easy, trim the branches of some of the trees to let the sun in. The second one is to try something else than a fescue. I would suggest Poa pratensis, aka Kentucky Blue Grass. Why? Because you said that poa annual grows easy. It might go dormant in the summer, but I doubt it with all the shade. Lastly, you could also try a fine fescue. I don't like fine fescues, but it might work in that area too.

I don't know anything about zoysia, so I can't comment on that approach.


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## alpine0000 (Jul 25, 2017)

I was going to mention some of the same stuff as g-man...

I had a shade problem too due to 5 large trees around my shed in my back yard. My only options were seeding with fine fescue or getting rid of the trees (or elevating the limbs them, which I tried the season before).

I hate fine fescue. So you can probably guess what I chose...


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## Ortho-Doc (Feb 3, 2019)

I've never thought about KY bluegrass. I dont know of any lawn in SC that use it. I'd have to see if it's a tougher turf than this wimpy, high maintenance tall fescue. The trees are so tall I can't limb them up and they are key to our privacy so they can't go.

Thanks for the input! I'll keep your ideas in mind.



g-man said:


> I saw this yesterday, but I've been busy with installing xps insulation to the rim joist.
> 
> I have a couple of ideas and some are crazy. Let's start with the easy, trim the branches of some of the trees to let the sun in. The second one is to try something else than a fescue. I would suggest Poa pratensis, aka Kentucky Blue Grass. Why? Because you said that poa annual grows easy. It might go dormant in the summer, but I doubt it with all the shade. Lastly, you could also try a fine fescue. I don't like fine fescues, but it might work in that area too.
> 
> I don't know anything about zoysia, so I can't comment on that approach.


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## samjonester (May 13, 2018)

It doesn't look like the Fescue is doing very well back there based on how patchy it appears to be. The best defense for you will be a thick lawn (after that, pre-emergent). If the Fescue you have isn't thick, then you'll need to figure out why. You'll have a difficult time keeping weeds away when there is bare dirt showing.

If you get enough sun for Tall Fescue, then it looks like it thinned out this summer and you didn't overseed. TTTF needs regular overseeds when it thins since it doesn't spread the way *** does.

If you don't get enough sun for Tall Fescue, then you may have better luck with Fine Fescue. Even if it works, you probably won't like its summer dormancy in the heat. You'll want to either eliminate all grass back there or find a way to get it more sun.


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## Ortho-Doc (Feb 3, 2019)

I agree @samjonester. I slit seeded last fall with GCI fescue, had amazing germination which was subsequently demolished by the wettest winter we've had in decades. This combined with this being in a low lying area welcomed in the poa annua to the party yet again.

Does anyone think a shade tolerant zoysia would be a tougher turf that could hold up better here? If not I may kill it all off and plant trees or some other material here. Anyone on this board ever naturalized a shady area? If so, I'd love ideas fur making a naturalized area look good.



samjonester said:


> It doesn't look like the Fescue is doing very well back there based on how patchy it appears to be. The best defense for you will be a thick lawn (after that, pre-emergent). If the Fescue you have isn't thick, then you'll need to figure out why. You'll have a difficult time keeping weeds away when there is bare dirt showing.
> 
> If you get enough sun for Tall Fescue, then it looks like it thinned out this summer and you didn't overseed. TTTF needs regular overseeds when it thins since it doesn't spread the way *** does.
> 
> If you don't get enough sun for Tall Fescue, then you may have better luck with Fine Fescue. Even if it works, you probably won't like its summer dormancy in the heat. You'll want to either eliminate all grass back there or find a way to get it more sun.


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## Chris LI (Oct 26, 2018)

@Ortho-Doc

Besides some tree trimming, why don't you try some shade tolerant TTTF cultivars? It sounds like your main issue was washouts during seeding. A reseed should take care of thickening up the turf to fight the poa. Although spring seeding is generally not encouraged, it may be a better option as opposed to looking at mud. If you blanket spray Tenacity at seed down as PreM, it would light up the poa to at least slow it down. I pulled the latest NTEP TTTF study from my files and screenshot the first two pages of shade tolerant cultivars. You don't need to go past the first page as the LSD value of 1.0 (level of significance) drops out from the highest ranked cultivar (Rowdy 7.1) or even #2 (Valkyrie 6.4). Anything 5.4+ would be good. I took a look at SSS's offering for their shade blend, and all four are highly rated (Rowdy, Valkyrie LS, Titanium 2LS, GTO). SSS is a bit pricey, but have a quality product. If you don't mind paying a premium, it might be worth it. If you have a preferred vendor or cost is a major consideration, see if you can find cultivars rated at least 5.4.





https://www.seedsuperstore.com/catalog/p-100073/ss1002-tall-fescue-shade-blend


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## Ortho-Doc (Feb 3, 2019)

@Chris LI I really appreciate you providing all of this information for me. While I appreciate that these shady tolderant fescues could work, I am nervous to possibly blow another growing season by waiting and hoping this fall my overseesing will work. I have had zero luck with spring seeding. This yr will make 3 straight years in a row the tall fescue overseeding failed and the poa won. I feel I am fighting a losing battle with each year I waste time and money on tall fescue. The heat and humidity just make it very difficult here in SC.


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## Suburban Jungle Life (Mar 1, 2018)

Have you done a soil test in the back areas which are struggling? Shade and lots of rain usually mean low ph and leaching of other nutrients. Optimal soil makes it easier for the grass to grow.

You could use tenacity and ethofumesate to control the poa-a. Though, without correcting the damp conditions, you'll still have problems if you stop...

Use tenacity and ethofumesate along with overseeding twice yearly expecting to do that forever...

Maybe change the drainage pattern so water doesn't sit in the low lying areas?

Try GCF air8? Many have had good success with it. It has worked surprisingly well for me. I'm sure it is soil dependent regarding results...

Perform an 8" core aerate, remove cores, and backfill with sand to aid in drainage from roots?

You could dig out the lowest area so it's even lower, 8" or so, and put in plants which like wet feet and essentially use it as a rain garden. It'll keep the other areas drier.

You could also take a patch of zoysia from the front and put it in the sad area of the fescue to see what happens to it.

Have you considered trying K31? I know it's not an optimal green but that stuff seems to survive the worst conditions somehow. No one wants it due to the color and blade width but I see it growing where many others struggle.

Grass doesn't grow everywhere. Fine fescue is the best with low light but it also isn't great if you don't fix the drainage. You could turn your back yard into a botanical garden type thing without grass. Paths to walk and beautiful plants. Lots of flowers. Of course, this is more work than grass...

Does the poa-a tend to stick around for the whole year? Many golf courses have poa-a as grass... I seeds itself... It seems to keep spreading... Maybe use a different mower for the back though...


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## quattljl (Aug 8, 2018)

I'm also in Rock Hill and have a similar situation. I'm no expert yet but here's what I noticed and how I would attack this.

Your backyard actually looks relatively flat. In your last picture, though, it looks likes there is a pretty good slope going down into the back yard. This could be a major factor to the extra wetness back there. You may need to consider some additional landscaping or hardscaping features to redirect the flow of water.

You do have a lot of trees around but the canopy looks very high (higher than the canopy of the trees at my house and I have TTTF growing underneath just fine) so I think you have enough sunlight to have success with TTTF. The moderate shade along with the slope into the back yard probably compound on each other. Perhaps a good shade tolerant cultivar in your next over seed could give you an extra bump.

I may have missed it, but I didn't see any mention of pre-emergent for the poa annua. Try all you want, but you can't over seed your way out of a poa problem.

I would recommend doing one more spring over seed this year, but you have to start very soon. Soil temps are already getting close to 55 degrees and I only anticipate about 1 more cold snap. Put down Scott's starter with Meso, and be very careful how much water you give it until you can get the drainage situation taken care of. Seems like any rainfall you get could make things too wet. I would also put down some RGS and/or Humic to get those roots developing before the summer temps hit. Hopefully this allows you to thicken up your stand and establish the over seed a bit to get it through summer. Once fall comes around, skip the traditional over seeding and do a heavy pre-m application for the winter annuals while also continuing your annual fall fertilizer program.


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## Ortho-Doc (Feb 3, 2019)

@Suburban Jungle Life your comments are incredibly insightful and helpful. I have attached my soil test from September. Since this test I have added calcify lime and also all my property is on Air8 and RGS. To help level out the low spots where the poa is rampant what soil would you recommend I use (sand? compost?). If I plug and seed again should I add tenacity and ethofumasate at time of seeding?

To answer your other question the poa dues out around end of June.

Thanks again. I really appreciate your input.


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## Ortho-Doc (Feb 3, 2019)

@quattljl you hit the nail on the head. The fescue lawn is fairly flat but sits at the low point for my whole street. The water drains surprisingly well except at a few large sections where the poa thrives. You were also correct that the tree canopy is pretty high.

I also agree about the point I can't oversed in the fall enough to outcompete the poa. Last fall I slit seeded and didn't do pre-emergent until well into November because I was ignorant about tenacity.

If I can figure out how to level my low spots in time I will core aerate and seed again. Is there any tool you know of that can help me establish a proper slope to the yard?

Finally, in the spots most heavily infested with poa should I glyphosate that first then level and seed?

Thanks again for your great advice.


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## quattljl (Aug 8, 2018)

Ortho-Doc said:


> Is there any tool you know of that can help me establish a proper slope to the yard?


Maybe a back hoe? lol Someone else might have a simpler solution but it looks to me like you may need some type of retaining wall or other drainage system to keep everything from running onto your turf when it rains.



Ortho-Doc said:


> Finally, in the spots most heavily infested with poa should I glyphosate that first then level and seed?


If there are large areas that are 100% poa with no fescue, I would put down glyphosate and reseed. Otherwise they will be bare dirt once the poa dies out this summer.

I guess another (but more expensive) option would be to nuke the poa now and lay sod. That obviously won't help your drainage issue but you'll have full turf coverage and won't have to worry about filling in or thickening your lawn this fall when you'll need to put down a pre-emergent.


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## Ortho-Doc (Feb 3, 2019)

@quattljl and @Suburban Jungle Life I just picked up Pennington KY31 blend 25 lbs and Pennington Smart Seed Dense Shade (5 lbs) along with Scotts Starter Fert with weed killer. My plan tentativty (unless the forum talks me off the cliff on this) is to glyphosate the sections of severe Poa along the periphery where drainage is the worst, then with a shovel edge out 2 feet along the worst drainage areas to create a trough an inch or two below the main grade to act as a drainage ditch for excess runoff. Then I will overseed the TTTF with the blend indicated above and add the starter fert.

Would the group recommend I order some tenacity and put that down at the same time to knock down the rest of the poa?


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## Green (Dec 24, 2017)

Ortho-Doc said:


> Would the group recommend I order some tenacity and put that down at the same time to knock down the rest of the poa?


In the same spot as the starter with Meso?


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## Ortho-Doc (Feb 3, 2019)

I was thinking Meso was a generic weed killer but now see it's the same active ingredient as Tenacity. I'd assume since it's a consumer product it's at a lower concentration. Would the grass need to be wet fur the granular Meso to stick and thus kill the poa?


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## g-man (Jun 15, 2017)

Mesotrisone is the active ingredient in Tenacity (brand name). Tenacity is sold as a liquid and could be use as a pre emergent via the soil (prevent targeted weeds from growing) or as a post emergent via foliar (leaf applied) using a non ionic surfactant.

Recently Scott's and some others are selling a starter fertilizer with mesotrisone part of a granular application. This granular application is meant for the soil as a pre emergent.

I have successfully controlled POA annua using Tenacity as a foliar application. I use a low rate (2oz/acre) with nis every week to 10 days. There are a couple of Univ studies around this. I know the other product that SJL listed is also good for POA annua, ethofumesate. I don't think the granular mesotrisone will control POA annua.


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## j4c11 (Apr 30, 2017)

I had a massive Poa infestation in my back yard and after trying all sorts of things for years, I skipped seeding and applied prodiamine 2 years ago in the fall - that got rid of 95% of the Poa. Did it again last fall, I'm down to exactly 1 small clump of Poa today. Going to seed this spring and spray prodiamine again this fall just to be safe. It's a sacrifice - the lawn has been looking like crap back there, but it's worth it.


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## Ortho-Doc (Feb 3, 2019)

@g-man thank you for this information. I will be placing my tenacity order today since the granular will not act post-emergently. The consensus is that if poa is the problem you must seed in the spring and pre-em in the fall (or ditch the cool season grass battle in the transition zone and change to warm season). That being the case I plan to glyphosate the poa tomorrow, aerate the ****ens out of it next weekend, level the cores out to even the lawn a bit, and overseed with ky31. My thinking is this tough fescue has a better shot at spring seeding each year.



g-man said:


> Mesotrisone is the active ingredient in Tenacity (brand name). Tenacity is sold as a liquid and could be use as a pre emergent via the soil (prevent targeted weeds from growing) or as a post emergent via foliar (leaf applied) using a non ionic surfactant.
> 
> Recently Scott's and some others are selling a starter fertilizer with mesotrisone part of a granular application. This granular application is meant for the soil as a pre emergent.
> 
> I have successfully controlled POA annua using Tenacity as a foliar application. I use a low rate (2oz/acre) with nis every week to 10 days. There are a couple of Univ studies around this. I know the other product that SJL listed is also good for POA annua, ethofumesate. I don't think the granular mesotrisone will control POA annua.


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## g-man (Jun 15, 2017)

In my opinion, I would not gly that area. Yes it has POA annua, but it is not a big deal. Golf courses actually plant it. It will die on the summer heat. Apply prodiamine in the fall to prevent more POA a next year. Like J4c11, break the cycle.


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## j4c11 (Apr 30, 2017)

Ortho-Doc said:


> aerate the ****ens out of it next weekend, level the cores out to even the lawn a bit, and overseed with ky31


Whatever you end up doing, do not core aerate before seeding in the spring. You'll stir up a lot of weed seed and it's going to be a mess - you can't apply herbicides for a while.


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## probasestealer (Apr 19, 2018)

Honestly this is a losing battle. If the TTTF is struggling, it's likely Zoysia won't last. At our last home in Raleigh, NC I tried every shade tolerant zoysia I could get my hands on and NOTHING worked. Some survived the summer, but never came back the next spring, or was too think to call a lawn. I eventually planted a fescue blend and just dealt..

If it were ME and I had the funds I would either cut down trees or clear the canopy to support your grass of choice (if possible) or kill everything, keep a constant pre-emergent barrier down and sod.

Tenacity is helpful in killing Poa, but it will be back and it can be a lot of work. There are millions of seeds just waiting to sprout..

You could look into more heat tolerant bluegrasses, I've been very impressed with SPF30 blended with NuGlade and Midnight. It handled the NC summer without any issues last year (other than where the contractors injured the turf)

Good luck!


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## Suburban Jungle Life (Mar 1, 2018)

j4c11 said:


> Ortho-Doc said:
> 
> 
> > aerate the ****ens out of it next weekend, level the cores out to even the lawn a bit, and overseed with ky31
> ...


You can put down tenacity and ethofumesate as pre when seeding fescue if you want. 2 apps covers 2 months and then you can use Prodiamine.


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## 2L8 (Mar 18, 2019)

probasestealer said:


> Honestly this is a losing battle.


I've been fighting against Poa annua and also Poa trivialis in lawn containing predominantly TTTF for several years now - with no success. As there are no herbicides against unwanted grasses available here, I tried to get rid of it mechanical.

So I spent many hours on my knees to pull out each unwanted plant I could identify. 4 years later the number of P. annua and trivialis plants hasn't decreased and I decided to kill half of the area with Glyphosate. I removed the top 1-2" and disposed it, passed about 10" of the soil through a sieve to filter out tons of rubble and pebbles and replaced the missing 2-4" by soil delivered as a turf-bearing layer. This contained a lot of sand and almost looked like pure sand when dry. I sowed one third of the also shady to very shady area with a mixture of 80/20 TTTF/KBG late fall 2017. It developed well until may 2018 when yellow rust infected the KBG. I also removed many Poa annua plants and a few other unwanted grasses, apart from lots of weeds.

During winter 2018/19 the turf became thinner, I had to rake out a lot of dead grass and after mowing the first time at the beginning of March I had to recognize that a lot of Poa annua and also few Poa trivialis had reappeared. I have to mention that here, 2018 was the driest since decades and last winter was about average.

It is very likely that the new soil contained unwanted seeds and also the grass seed may have been contaminated, even though is was not the cheapest.

I only write this to let you know, how difficult it may be to eliminate Poa annua and trivialis.

But maybe there is hope with another grass seed-mixture. On another third of the area, I sowed a mixture containing Poa supina, which is used here as the best shadow tolerant grass. So far it looks ok, but it suffered from drought last year. It is very similar to Poa annua but produces stolons, blossoms only in April to May and spreads even more aggressive than Poa annua.

I doubt whether the climate in SC is appropiate for this supina bluegrass, but if Poa annua survives summer (as a plant), Poa supina may also do.

But I do not have much experience with Poa supina so far. The growth habbit and the light green color is the opposite of what I perfer, but if it feels comfortable in the shadows, survives in the sun and more important replaces unwanted grasses, I will swallow that pill.


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