# Confusing effects of Tenacity



## baker86 (Sep 5, 2017)

New Home Owner. Moved in on April 1, 2017.
*Location*: Colorado, 5b
*Grass Type: Rye/Fescue/KBG mutt mix

Just wanted to first give a shoutout to this forum, I've learned so much with you guys.

On the 12th (10 days ago) I aerated, overseeded, fertilized with Milorganite and Scotts Starter Fert with Tenacicty.

This morning, (10 days later) I woke up to quite a bit of my lawn being white tipped - from the Tenacity.

Since overseeding, I've noticed a lot of nutsedge coming in, which I will deal with later - I am sure this is because of the watering like crazy, and expected this.

But some of the grass that I thought was fescue, is also turning white.

See here:


http://imgur.com/6nPbC


Some of the photos are obviously nutsedge. Photos 6, 7, and 8 scare me the most as I thought that was just "grass" and not weeds. If this is a weed, then my entire lawn is a weed.

If it is a weed(s), then what is it?*


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## SNOWBOB11 (Aug 31, 2017)

Tenacity can whiten good grass too. I don't think that's weeds in the pics you have. I think it's just good grass being bleached by tenacity. It should go away soon. When I sprayed tenacity on my kbg reno this year there were many areas of kbg that came up with white blades. They weren't weeds just good grass that got a bit bleached.


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

baker86 said:


> ...
> *Grass Type*: Rye/Fescue/KBG mutt mix
> 
> ... fertilized with Milorganite and Scotts Starter Fert with Tenacity.
> ...


I mentioned this in another posting on the site, but it bears repeating:

Be careful using "Scotts Starter Fertilizer with Weed Preventer" in lawns with significant amounts of fine fescue in their "northern mix" or with a mostly fine fescue area (say an old northern mix which has a shady area which has been reduced to mostly fine fescue over the years) or you could have a problem if too much fertilizer with mesotrione is applied.

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

Hopefully, if you didn't overapply the fertilizer with mesotrione, the fine fescue in your lawn will recover, but FF will succumb to heavier doses of mesotrione.


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## coreyndstuff (Aug 14, 2017)

I had a very similar experience. I followed nearly the same process as you and a week later a _lot_ of my lawn was turning white. The only explanation is that half of my back yard was in fact bent grass, not something non-weedish.


*note: the image has an instagram filter on it that i thought illustrated how much was turning white*

heres a non filtered version


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## baker86 (Sep 5, 2017)

Corey, did the lawn come back? That's terrifying.


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## MarkAguglia (Jul 13, 2017)

I sprayed Tenacity over a month ago. Much of the good grass around my clover areas also turned white, but in time it came back just fine. Unfortunately, so did much of the clover. &#128540;


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## j4c11 (Apr 30, 2017)

Tall Fescue turns white pretty easily with Tenacity. It will grow out of it.


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## Kigiin (Sep 10, 2021)

I was planning on making a second application of tenacity after two weeks but the first application turned a lot of good grass white, so worried a second application might actually kill some good grass.

Although maybe that is a lot of weed grass from re-seeding last fall - not sure.

Thoughts?

I got a green cheetah thing going on!



I pulled some of the white stuff and it does look like two different grasses: on the left looks like a blade grass while on the right the stems are round and then branch out. Wish I was an agronomist.



A little disappoint so far this spring, as it looked like this last October:


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