# Fine Fescue Herbicide



## SpiveyJr (Jun 7, 2018)

Is there any selective herbicide that will kill FF and not tall fescue and kbg? It seems unlikely to find something that won't kill the tall fescue as well.


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## Turfguy93 (Aug 30, 2017)

If you feed the kbg well it should make the fine fescue thin out depending on shade. Fine fescue didn't like a lot of nitrogen. I doubt you will get rid of it completely though


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## social port (Jun 19, 2017)

@SpiveyJr look into tenacity. When applied correctly, it is safe for tall fescue. It is known to bleach fine fescue. It may also lead to some damage or something more significant. It is worth checking out the label.


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## g-man (Jun 15, 2017)

I have not tried this and I want to, but I would likely just use round up and reno.



ken-n-nancy said:


> For an illustration of what too much mesotrione will do to fine fescue, see slide 24 of Tenacity: A New Herbicide for Turfgrass Establishment from Washington State University.


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## Green (Dec 24, 2017)

Not that I know of, but managing for KBG, letting the FF drought stress, using Tenacity, dethatching and overseeding every so often definitely help.


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## Green (Dec 24, 2017)

Also I have killed FF with an 8-10 oz per acre rate of Tenacity used accidentally, but also killed some KBG with it.


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## SpiveyJr (Jun 7, 2018)

Using tenacity sounds promising and I happen to have a bottle on hand. I'm actually getting ready to spot treat weeds and grassy weeds for my overseeding next month. I don't expect complete kill of the FF but if I can damage it and cover lightly with soil maybe I can get the new seed to overtake it.

My plan is it spray Triad Select and Triclopyr week 1 (this weekend) with a follow up next weekend, and tenacity at 4 oz (July 28) every other weekend with seed down at the 3rd Tenacity app (August 25).


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## gene_stl (Oct 29, 2017)

If you want to kill it "accidentally" sulfentrazone(Dismiss) with spreader sticker will probably hurt ff more than Tenacity.


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## ken-n-nancy (Jul 25, 2017)

g-man said:


> I have not tried this and I want to, but I would likely just use round up and reno.
> 
> 
> 
> ...


I'm planning to apply Tenacity at an 8oz/acre rate to a 1500sqft section of my lawn with a 5-year-old northern mix that is basically just KBG and FF now (winter kill from 5 NH winters has taken care of most of the PRG) to try to reduce the FF. I'm planning to make that application around August 15, but will be adjusting the date based upon weather at that time, hoping to catch the FF just as it comes out of summer dormancy here in NH.

Why am I trying to reduce the FF in that section? Well, basically, the FF goes brown in the sunnier areas during July, even though it does great in spring and fall. This is particularly true right near the road, where the extra sun, heat, and drier soil make the FF turn brown while the Prosperity KBG copes with that environment.

I've tried the "lots of nitrogen" to favor the KBG over the FF, and it does favor the KBG, but the FF doesn't shrink back by any means. I've read that too much N is bad for FF, (turfguy93 mentions this above) but I've never personally seen that in my lawn. In 2016, my total application was 9.4#N/ksqft, which the KBG absolutely loved. The FF didn't go into "overdrive" like the KBG did, but it sure did better with the high N levels than it had been doing a couple years earlier at more conventional N levels around 3#N/ksqft. I think it's just that once one gets much over about 3#N/ksqft on FF, the marginal gains from additional N diminish so that eventually the become close to zero additional gain. I've never seen the marginal gain become negative for FF, even up to 9#N/ksqft. (I haven't tried going higher than that, and won't, because the disease pressure on the KBG surged at those very high N levels.)


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## Green (Dec 24, 2017)

ken-n-nancy said:


> Why am I trying to reduce the FF in that section? Well, basically, the FF goes brown in the sunnier areas during July, even though it does great in spring and fall. This is particularly true right near the road, where the extra sun, heat, and drier soil make the FF turn brown while the Prosperity KBG copes with that environment.


I have a small area like that. Overseeded it again last year. Looks a bit rough now from brown grass and red thread damage.

Guessing the area you speak is not part of your potential reno area? I don't like doing renos in tough areas like near roads...so are you trying to encourage the mature grass?


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## SpiveyJr (Jun 7, 2018)

gene_stl said:


> If you want to kill it "accidentally" sulfentrazone(Dismiss) with spreader sticker will probably hurt ff more than Tenacity.


I was looking at Dismiss but I thought I read that it kills Tall Fescue as well?


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## gene_stl (Oct 29, 2017)

Dismiss IS hot stuff. But fine fescue seems to be more sensitive to herbicides than tall. I think a reduced rate might be able to be selective. It would be an experiment. They are after all the same species.


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## SpiveyJr (Jun 7, 2018)

I'm so tempted to accidentally overdose my lawn with Dismiss and then dump KBG seed down... I think I'll try my luck with Tenacity first. I already have some other weird type of grass in the lawn that is a group along with small groups of fine fescue. If a blanket app of Tenacity doesn't work, glyphosate will.


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## Roosterchest (Aug 3, 2017)

I hate FF. Unless it's under total shade it doesn't do well as a "northern mix" except make your lawn look poor when the temps push upper 80's. It's basically the sole reason I'm systematically renovating portions of my lawn. Rather than mess around I'd just RU and plant the newest variety of grass you prefer.


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## ken-n-nancy (Jul 25, 2017)

SpiveyJr said:


> I'm so tempted to accidentally overdose my lawn with Dismiss and then dump KBG seed down...


  I think you're joking about this, but if you're not, make sure you read the label for Dismiss carefully. I think there is a caution against using Dismiss within some time (30 days? 60 days?) before seeding new grass. In other words, if you applied Dismiss to kill the FF and then seeded KBG a few days later, you may get very poor germination or growth from the KBG due to the recent Dismiss application.

I know that glyphosate doesn't affect subsequent seeding. Actually, before I toss out new seed, I spray one last application of glyphosate on the seedbed an hour before seeding, just to get any just-germinated weeds that may even be too small to really see!


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## SpiveyJr (Jun 7, 2018)

Yea I'm definitely joking about using Dismiss, but you do bring up some good points about using it prior to overseeding.


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## SoFRESHnSoGreenGreen (Jun 8, 2021)

any updates on getting rid of that fine fescue? Im having the same issue. some idiot thought itd be a good idea to sod our home before selling and its a kbg, fine fescue blend. that shit sucks! why ruin kbg with a weak *** grass like that? im going to thatch/overseed heavily this fall and hope that helps, but the front yards are getting smoked off and fully renovated.


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## g-man (Jun 15, 2017)

I dont think I've seen anyone with real success in getting rid of selectively getting rid of fine fescue.


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## M32075 (May 9, 2019)

Nuke it start over your chasing your tail trying to selectively get rid of fine fescue in a mixed lawn. Even a over seed is not going to help.


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## SodFace (Jul 17, 2020)

SoFRESHnSoGreenGreen said:


> any updates on getting rid of that fine fescue? Im having the same issue. some idiot thought itd be a good idea to sod our home before selling and its a kbg, fine fescue blend. that s--- sucks! why ruin kbg with a weak @ss grass like that? im going to thatch/overseed heavily this fall and hope that helps, but the front yards are getting smoked off and fully renovated.


Super common here too. Is it so the sod grower doesn't look so bad when people lay it down in shady areas? Some of the fine fescue survives I guess?

Most seed blends sold here are KBG/PRG/Creeping Red Fescue. I think it's fine in many applications but harder to source non FF seed/sod. We have a couple farms that do %100 KBG though.


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## ken-n-nancy (Jul 25, 2017)

g-man said:


> I dont think I've seen anyone with real success in getting rid of selectively getting rid of fine fescue.


+1

I did an experiment a few years ago with heavy Tenacity applications to eliminate fine fescue from a KBG/PRG/FF northern mix section of our lawn. I think that maybe 25% of the FF succumbed, but that also means that 75% of it survived.

Last fall, I fully renovated that section of the lawn to 100% KBG (a Prosperity/Bewitched blend) and the problem is solved.

In my small shady back yard, I have a FF/KBG mix of shade-tolerant varieties. When a small patch dies off from disease or similar, the KBG does the spreading thing (sometimes encouraged by my using plugs from a ProPlugger) and fills that area back in with just KBG. So, very gradually over time, I think it is becoming increasingly KBG, but there's still a lot of FF there.

At least with that area being shady, the FF remains generally green and healthy in the summer -- well, except for the sunniest areas, where the summer heat sends the FF into dormancy for a few weeks before leaping back with a vengeance in the fall.


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## Scagfreedom48z+ (Oct 6, 2018)

ken-n-nancy said:


> g-man said:
> 
> 
> > I dont think I've seen anyone with real success in getting rid of selectively getting rid of fine fescue.
> ...


What rates did you use for the tenacity apps?


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## ken-n-nancy (Jul 25, 2017)

Scagfreedom48z+ said:


> ken-n-nancy said:
> 
> 
> > I did an experiment a few years ago with heavy Tenacity applications to eliminate fine fescue from a KBG/PRG/FF northern mix section of our lawn. I think that maybe 25% of the FF succumbed, but that also means that 75% of it survived.
> ...


I used two doses of Tenacity at 8oz/acre. More information can be found in my lawn journal for that year - Ken-n-Nancy's Lawn Journal 2018-19 - "War on Triv". Most of the journal is about a front lawn renovation, but posts are scattered throughout about the Fine Fescue Thinning Experiment with Tenacity. Searching through the thread for "Tenacity" will help find those postings, such as this post after the second application was made.

As a result of the "ineffective" experiment to eliminate the fine fescue, I renovated that section of our lawn last fall. It is now at the 1-year mark and I'm glad to have done the renovation.


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## Scagfreedom48z+ (Oct 6, 2018)

ken-n-nancy said:


> Scagfreedom48z+ said:
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> 
> > ken-n-nancy said:
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Wow, so you put down 16oz total or split apps of 4oz's per app?

I have the generic Meso 4SC and it states you can put down 5-8oz per acre as a pre/post em. I'm mostly using it to knock back the Poa A, coupled with Etho. I want to do split apps of the meso but trying to figure out the best rate per acre to go with. Any advice? Mostly TTTF for a lawn. I was thinking of splitting .11 oz into 2 separate apps, at seed down and then at 4 weeks post germination of the tttf

Im really hoping that I'm able to get TTTF that I'm going to overseed, take over the FF areas. Im going to scalp it down, apply the 2 herbicides together at seed down and then apply them separately germination depending. That should hopefully put a dent in the FF, along with the Poa a, to give it time to grow in and take over


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## ken-n-nancy (Jul 25, 2017)

Scagfreedom48z+ said:


> ken-n-nancy said:
> 
> 
> > Scagfreedom48z+ said:
> ...


To try to get rid of the fine fescue (FF) in a northern mix, I applied 8oz/acre in one application, and then two weeks later, again applied 8oz/acre in a second application. Yes, that is the label's indication of the yearly maximum.



Scagfreedom48z+ said:


> I have the generic Meso 4SC and it states you can put down 5-8oz per acre as a pre/post em. I'm mostly using it to knock back the Poa A, coupled with Etho. I want to do split apps of the meso but trying to figure out the best rate per acre to go with. Any advice? Mostly TTTF for a lawn. I was thinking of splitting .11 oz into 2 separate apps, at seed down and then at 4 weeks post germination of the tttf


For prevention of weeds at seed-down, I've had good success with Tenacity (mesotrione) applied at the time of seeding, following label instructions.

When I applied Tenacity (mesotrione) to a mature northern mix in an attempt to eliminate the FF, everything was significantly bleached after the first app, and then the second app was applied at about "peak bleaching" from the first app. The Kentucky bluegrass (KBG) all recovered, as far as I can tell, and nearly all the fine fescue (FF) did, too. Further back in that thread are some links to some studies on high rates of Tenacity (mesotrione) on different grass types. It was upon those studies that I based my experiment, as it had been documented in that study (and elsewhere) that the 8oz/acre rate could severely damage FF. However, I have no experience with turf-type tall fescue (TTTF), so I can't really provide any first-hand advice on that.



Scagfreedom48z+ said:


> Im really hoping that I'm able to get TTTF that I'm going to overseed, take over the FF areas. Im going to scalp it down, apply the 2 herbicides together at seed down and then apply them separately germination depending. That should hopefully put a dent in the FF, along with the Poa a, to give it time to grow in and take over


Personally, I've never had success with selective elimination of FF from other grasses. For all of its looking frail, or going dormant in summer for various reasons (too hot, too dry, too much sun), or developing "empty spots" in an all-FF lawn, _*fine fescue is one tough grass*_ to actually kill selectively if you want the FF all gone, but want to keep the other grass.

On the other hand, I've done about a half dozen renovations now, all of which looked like a lawn within a few months (and always better than the previous one that was there within six months.) If you want no FF in some other lawn, I'd suggest killing it all and renovating to plant what you want. The one exception I could think of would be if you have a sufficiently steep slope that erosion and/or holding seed on the slope is likely to be a big problem. However, even then, I'd be inclined to kill the old lawn, not disturb the soil to let the old roots hold the soil in place and do something such as a seeding blanket or "hydroseed" to retain the new seed on the slope during germination.


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