Product Features

  • Controls over 46 broadleaf weeds & grasses
  • Selective pre- and post-emergent weed control
  • Use when seeding cool-season lawns to prevent weeds from germinating
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Average Rating

4.5 out of 5 stars Rating: 4.3

618 Reviews | 675 Q&A

Product Overview

Tenacity Herbicide is a systemic pre-emergent and post-emergent herbicide for the selective contact and residual control of weeds in turfgrasses. Tenacity can be used for weed control prior to or during seeding of certain turfgrasses during renovations. When applied as a pre-emergent, weeds absorb Tenacity during emergence from the soil. Dry conditions following application may reduce the pre-emergence activity. If rainfall (0.15 inches) has not occurred within 10 days after a pre-emergence application, activate with 0.15 inches of irrigation.  When used as a post-emergent, Tenacity weed killer is absorbed by susceptible weeds through foliar contact and soil absorption. Foliage of treated weeds cease growth after application, then turn white (loss of chlorophyll) and death may take up to three weeks. A repeat application is required after two to three weeks for improved post-emergence weed control. A non-ionic surfactant should be added in post-emergence applications.

We also offer the Tenacity Herbicide Kit with Surfactant and Spray Indicator Dye which includes one 8 ounce bottle of Tenacity Herbicide, one 32 ounce bottle of Turf Mark Blue Spray Indicator Dye, and one 8 ounce bottle of Hi-Yield Spreader Sticker Non-Ionic Surfactant.

PLEASE NOTE:

  • Tenacity is NOT for use on Bermudagrass when actively growing or St Augustine home lawns.
  • Tenacity does NOT provide post-emergent control of Poa Annua.  It will only provide suppression of Poa Annua when used as a pre-emergent.  
  • When treating for clover, or suppression of bermudagrass, it is recommended to tank mix Tenacity Herbicide with Turflon Ester for more improved control.  Please see Supplemental Label 2(ee) for complete instructions.   This 2(ee) Recommendation applies to the following turf species only: Tall fescue, Kentucky Bluegrass, and Perennial Ryegrass.
 

Syngenta has recently updated its Tenacity packaging.  You may get either the new packaging or the old packaging until all of the old packaging style has been depleted.  There is no change to the product itself, only the exterior packaging.  

Features and Specs

Active Ingredient Mesotrione 40%
Target pests Barnyardgrass, Carpetweed, Chickweed, Clover, Crabgrass (large & smooth), Dandelion, Foxtail, Goosegrass, Henbit, Yellow Nutsedge, Purslane, Thistle, Wild Carrot and others
* See label for complete list
For use in Kentucky Bluegrass, Centipedegrass, Buffalograss, Tall Fescue, Perennial Ryegrass, Fine Fescue, St. Augustine Grass (grown for sod only)
Application 4 - 8 oz. per 30 gallons of water per acre
* Use a Surfactant to Increase Effectiveness
* See label for complete application instructions
Formulation Professional Product
Group 27 Herbicide
NOT FOR SALE TO AK, PR
Shelf Life 3-5 years from date of manufacture when properly stored. Keep out of direct sunlight and extreme temperatures
Shipping Weight 0.81 lbs
Manufacturer Syngenta (Mfg. Number: 46256)
EPA Registration 100-1267

Details

What makes Tenacity different than other currently used turf herbicides?

Tenacity is a selective, systemic herbicide that features a new mode of action for pre- and post-emergence grass and broadleaf weed control in several cool- and warm-season turf species—like keeping bentgrass out of your rough. Tenacity can also be applied on established or newly seeded turf.

How was Tenacity herbicide discovered?

A Syngenta scientist in California noticed that there were fewer weeds growing under his bottlebrush (Callistemon citrinus) plant, far fewer than can be explained by shading alone. He concluded that the plant must be producing allelochemicals to suppress weed competition. Syngenta synthesized mesotrione based on the allelochemicals produced by the bottlebrush plant.

What is the mode of action of Tenacity herbicide?

Tenacity inhibits a plant enzyme called HPPD that is essential to photosynthesis and prevents formation of carotenoids in susceptible plant species. Without carotenoids, light energy and by-products of photosynthesis will destroy chlorophyll and cell membranes. This results in bleaching of leaves followed by necrosis and death of the plant.

How quickly does Tenacity work?

Once absorbed, Tenacity quickly translocates throughout the plant. Weed growth is suppressed soon after application, as photosynthesis is disrupted. Death of the plant usually occurs within two to three weeks.

What are some of the unique benefits of Tenacity herbicide?

Tenacity has pre- and post-emergence activity on 46 dicot and monocot weed species. It can selectively control perennial monocots such as bentgrass and nimblewill and annuals such as crabgrass and goosegrass in many turfgrass species. Tenacity can be applied at the seeding to prevent weed germination and allow the turfgrass species to establish without weed competition.

Can Tenacity be used to get bentgrass out of roughs and fairways?

Yes. Tenacity selectively controls bentgrass out of Kentucky bluegrass, perennial ryegrass, and tall fescue turf.

What does it mean that Tenacity was granted reduced-risk status by the EPA? Why did Tenacity earn this status?

Reduced-risk is an EPA designated registration status that accelerates the process for registration of certain new plant protection products. Tenacity received reduced-risk status by the EPA based on its unique mode of action, low use rates, and favorable toxicity and human health profiles, as compared to other herbicides currently on the market.

On which grasses has Tenacity been tested for use at or prior to seeding?

Tenacity is safe for use at or prior to seeding on Kentucky bluegrass, tall fescue, perennial ryegrass, and centipedegrass. Application at seeding can be made to fine fescue only if it is less than 20% of a seed mixture.

Are there any grasses on which you can't use Tenacity?

Tenacity is not recommended for use on zoysiagrass, hybrid or common bermudagrass, seashore paspalum, or kikuyugrass.

Can Tenacity be tank mixed with other herbicides?

Tenacity can be tank mixed with Barricade, dicamba, carfentrazone, triclorpyr, atrazine, simazine, s-metolachlor, bentazon, and several three-way phenoxy herbicides. Combinations can help turf managers broaden the weed control spectrum or improve the level of weed control over single-product applications.

How rainfast is Tenacity?

Tenacity is rainfast within several hours under normal rainfall conditions.

What other brands currently on the market offer a product similar to Tenacity?

There are currently no other herbicides like Tenacity for golf courses and sod farms registered for use or sale in the U.S. Tenacity will compete with multiple products from different classes of chemistry.

Review Search   
Sort Reviews
  • 5 of 5 Stars

    Tenacity Herbicide

    By Frank on 05/07/2012

    Verified Purchase

    I had a lot of weed grasses in my yard and they were invasive and spreading over the whole yard. Tenacity targets weed grasses and kills them while leaving the rest of the yard in tact and that is exactly what it did. All of my weeds are dying. One thing you must note is that this herbicide needs to be watered after it dries on the plant so that the plant takes it in. It will not work if you just spray it on and don't get rain or water it for a couple of weeks. It's pricy but I know of no other chemical that will kill weed grasses and leave what you want, alone.

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    643 of 672 people found this review helpful

  • 5 of 5 Stars

    A Miracle Herbicide!

    By Margaret on 08/14/2012

    Verified Purchase

    I had a lawn that was completely taken over by bentgrass. I used round up on the lawn and put in an entire new lawn. All was well for a year or two. Then the the bentgrass came back in a few isolated areas. I would have to round them up at the end of the season and reseed. This went on for a number of years. When I learned about Tenacity I was thrilled and gave it a try. It works wonderfully! Yes it is pricy, however it beats having to round up the bentgrass, clear it out, put down more top soil and reseed. Try it...you won't be disappointed.

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    404 of 420 people found this review helpful

  • 5 of 5 Stars

    Death of Nimblewill grass

    By David on 10/02/2015

    It took a while, but the grass and other weeds are all white/dying. I used three teaspoons of "Dawn Ultra" & one teaspoon of Tenacity to two gallons of water, per a study by Ohio State University.

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    364 of 380 people found this review helpful

  • 5 of 5 Stars

    Great product! Does exactly what it advertises!

    By Debi on 09/07/2012

    My mom completely re-sodded front and back lawns and within 3 years it had been invaded by bentgrass. My new lawn was hydro-seeded 5 years ago in a new subdivision that used to be a golf course. Our methodology was to use Roundup in the fall (when the bent grass really seems to take off in growth) and then reseed the large killed off areas, hoping that the Roundup did a thorough job in killing the bentgrass. This becomes very tedious every year, not to mention the expense. We waited a few years for Tenacity to be available to the public and have both been having great results with the product. The good thing is that the remaining blades of good turf remain green in the kill zone. That gives me hope that I may not have to reseed, just wait for the good turf grass to fill in by itself. Our lawns are a combination kentucky blue and fescue blends. My only complaint is that the product is so concentrated and thick. The high concentration makes it even more critical to measure accurately! Not too crazy about the enclosed syringe measuring device. I feel it is too difficult to use and the potential to spill is high. I would love if there could be a more diluted Tenacity product to purchase for the average homeowner. That would make the product easier to measure, plus ensure a bit of wiggle room on the measurements?

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    334 of 360 people found this review helpful

  • 5 of 5 Stars

    No more Crabgrass!!

    By Rob on 08/23/2012

    Verified Purchase

    This product really works. It does take time, so be patient. I still have to apply the second application to finish off the Crabgrass!!! It won't take much, the plants are almost dead now after 2 weeks.

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    274 of 283 people found this review helpful

See all 618 customer reviews

Questions & Answers

Have a question about this product?
  
Sort Questions
Q
Is it safe to spray Tenacity on 3 week old tall fescue?

Just over seeded and my new grass is starting to grow. Can i use this product without hurting my new grass?

A

Yes, Tenacity can be applied after 2-3 weeks from seeding.

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Q
Can I use Tenacity Herbicide and Moss Out the same day but two different applications
A

You would want to wait 24 hours after the application of 1 product before applying the second product.

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Q
Mixing Tenacity

Can I mix tenacity with organic liquid fertilizer and liquid humic acid at the same time or just one at a time? It would be so helpful if I could do both at the same time.

A
It may be fine to mix those products with Tenacity Herbicide but has not been tested by the manufacturer. We recommend that you perform a jar test on an inconspicuous area first prior to a full application to confirm if you wish to use them both together.

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1 of 2 people found this answer helpful

Q
Can I mix Tenacity Herbicide with 2,4 D?
A

Since Tenacity Herbicide requires a surfactant as a post-emergent, we would not advise mixing it with a product that does not require one. If both products require a surfactant, you would need to a jar test to see how they both react together. Keep in mind that as a post-emergent it can only be spot treated & not blanked sprayed the way other post-emergents can

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Q
Can Tenacity be successfully applied during in Fall during 2 week window

I realize 55 degrees is optimal temperature for application of Tenacity. Currently air temperature is in 30-45 range however, forecasts are calling for a 2 week period of temps over 55 degrees. Would Tenacity kill broadleaf weeds during that two week window? I'm not concerned about crabgrass since it dies off with first hard frost.

A
Pre-emergents such as Tenacity Herbicide can be applied both in the spring & fall. They are applied once soil temperatures reach below 70 degrees, which are different from the air temperatures. Most of the US has already reached the point where they can go ahead & apply pre-emergents. Even though Tenacity can work as both a pre & a post, due to soil temperatures it will only work as a pre-emergent. Meaning it will only prevent germination not kill what's already germinated. 

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Q
Is this safe to use on centipede and Bahia grass lawns?
A

Yes! According to the label, Tenacity Herbicide is safe for use on Centipede and Bahia. 

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Q
I have a PRG lawn. Sprayed Tenacity on 4/7. How long do I have to wait to overseed with PRG?
A

If seeding was not applied close to or at the same time as the application of Tenacity Herbicide for pre-emergent control, you will need to wait 3 weeks to seed new perennial ryegrass. 

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Q
Will tenacity kill field manor
A
Tenacity Herbicide is not labeled to treat field madder. 

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Q
How long should I wait after using Tenacity before I plant zoysia plugs?
A

You will want to wait a month before planting the zoysia plugs after applying Tenacity Herbicide.

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Q
Will tenacity kill or control dallisgrass?
A

Per the product label, dallisgrass is sensitive to Tenacity. You should avoid spraying these turf areas. Please let us know if you are trying to get rid of dallisgrass or if you want to treat other weeds in dallisgrass. We would be happy to select a product that will fit your specific needs. For free expert advice, please call us at toll-free 866.581.7378 M-F 9-5 PM EST.

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Q
Does grass need to be dry when appling tenacity?
A

It would be best to wait to apply Tenacity Herbicide when weeds are dry. Be sure to mix in a surfactant like NonIonic Surfactant

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Q
I used this, but now spinach looking weed is growing.

I live in the Rio Grande Valley (south Texas) I sprayed this, and all the weeds died, but then spinach looking weed began to grow months later where i sprayed. Everywhere i sprayed that weed came out. It's taking over the grass.. I'm not sure what to spray to kill it. I think my grass is bermuda and st augustine.

A
Tenacity Herbicide is not labeled to kill wild spinach. You can Glyphosate based products to treat and reseed in the bare areas. 
 

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Q
Does Tenacity influence the timing of Fertilizer application? If so, how??
A
We recommend waiting 2-4 weeks between applications of herbicides and fertilizers to avoid over stressing the treated areas. We recommend using a soil analysis test kit or taking a sample of your soil to your local cooperative extension so your soil can be analyzed to determine what nutrients your soil is lacking. The healthiest, hardiest lawns are fertilized 2-4 times per year, fall, summer, early spring and late spring.  We do have a soil test kit here.
 

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Q
Will freezing temperatures affect concentrated Tenancity?

My Tenacity order was left undetected in my mailbox for several days with temperatures well below freezing. Will it be affected?

A
Tenacity can start to lose its efficacy when it is not stored properly. Freezing temperatures can cause the product to not work correctly.

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Q
Application of Tenacity Herbicide after pre germinated grass seed.

If I pre germinate my rye grass seed & plant them when roots are just starting to form, can I apply Tenacity at the same time or would I need to apply Tenacity before I plant them?

A

Tenacity Herbicide is best applied 2 weeks before planting/seeding a lawn or wait at least 2-3 weeks after seeding to apply.  When pre-germinating and planting in the area we would recommend waiting at least 4 weeks to apply so it is established.

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3 of 4 people found this answer helpful

See all 675 customer questions

Tenacity Herbicide 4.5 out of 5 stars Rating: 4.3 (618 Reviews / 675 Q&A)

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