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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$66.64

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Average Rating

4.5 out of 5 stars Rating: 4.3

618 Reviews | 678 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. 

Tenacity New 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

Tenacity Herbicide is a professional-grade, selective weed control solution that works both before and after weeds emerge. Powered by the active ingredient mesotrione, it targets over 40 grassy and broadleaf weeds while remaining safe for many common lawn types. Its unique ability to be used during seeding sets it apart from most traditional herbicides.

 

What Weeds Does Tenacity Herbicide Control?

Tenacity controls over 40 weed species, including both grassy and broadleaf weeds such as:

  • Crabgrass
  • Goosegrass
  • Bentgrass
  • Nimblewill

It is especially valued for controlling difficult perennial grassy weeds in turf. See the label for the full list of weeds that Tenacity will kill.

 

What Grass Types Can Tenacity Be Used On?

Tenacity is safe for use on many cool- and some warm-season grasses, including:

  • Kentucky bluegrass
  • Tall fescue
  • Perennial ryegrass
  • Centipedegrass

It can also be used at or before seeding these grasses. See the Tenacity label for a full list of grass types.

 

What Grass Types Should NOT Be Treated with Tenacity?

Do not use Tenacity on:

  • Zoysiagrass
  • Bermudagrass (common or hybrid)
  • Seashore paspalum
  • Kikuyugrass

Using Tenacity on these grasses may result in injury or discoloration. Always read the label and follow the instructions when using an herbicide like Tenacity.

 

Can I Seed or Reseed After Applying Tenacity Herbicide?

Yes. Tenacity is one of the few herbicides that can be used at or near seeding time.

  • You can apply Tenacity at the time of seeding or immediately after for most grass types
  • Exception: Wait 2–4 weeks before seeding fine fescue

When Should Tenacity Herbicide Be Applied for Best Results?

Tenacity works as both a pre-emergent and post-emergent herbicide, making timing flexible:

  • Pre-emergent: Apply before weeds germinate to prevent growth
  • Post-emergent: Apply to actively growing weeds

For optimal performance:

  • Apply when soil temperatures reach ~55°F or higher
  • Ideal air temperatures are typically 65°F–85°F
  • Avoid applications when temperatures exceed 85°F
 

How Much Tenacity Herbicide Per Gallon of Water?

For small, spot-treatment applications, mix 0.5 teaspoons of Tenacity Herbicide per 1 gallon of water to treat approximately 1,000 square feet.

For best results, add a non-ionic surfactant at 1.5 teaspoons per gallon to improve weed control by helping the product stick to and penetrate foliage.

 

How Long Does Tenacity Herbicide Take to Work?

Tenacity begins working soon after application:

  • Weed growth is suppressed within days
  • Visible whitening (bleaching) may occur in 1–2 weeks
  • Complete weed death typically occurs within 2–3 weeks

This whitening effect is normal and indicates the herbicide is disrupting photosynthesis.

 

Does Tenacity Need to Be Watered in After Application?

No, Tenacity does not need to be watered in when used as a post-emergent herbicide.

  • Allow at least 6 hours of dry time after application before rain or irrigation
  • Watering too soon may reduce effectiveness
 

How Rainfast is Tenacity Herbicide?

Tenacity Herbicide needs about 6 hours to fully dry on the plant before rain or watering. After this time, rainfall or irrigation should not reduce its effectiveness.

 

What Makes Tenacity Different from Other Herbicides?

Tenacity stands out because it features a unique mode of action (mesotrione) that:

  • Controls weeds both pre- and post-emergence
  • Selectively targets weeds without harming labeled turfgrass
  • Allows use during seeding, unlike most herbicides
  • Effectively controls tough grassy weeds like bentgrass and nimblewill

Currently, there are no direct equivalents with the same combination of selectivity and versatility available for residential turf use.

 

Can Tenacity Be Mixed with Other Herbicides?

Yes, Tenacity can be tank mixed with other compatible herbicides to broaden weed control, including:

  • Barricade
  • Atrazine
  • Simazine
  • Dicamba
  • Triclopyr
  • Three-way herbicides

Always follow label instructions and perform a compatibility test before mixing.

 

What Are the Key Benefits of Using Tenacity Herbicide?

  • Dual-action: pre- and post-emergent control
  • Controls hard-to-kill grassy weeds
  • Safe for use during lawn establishment
  • Works on over 40 weed species
  • Unique chemistry not found in other residential herbicides

Tenacity Safe for Seeding

 

Tenacity Herbicide What to Expect

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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    648 of 677 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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    405 of 421 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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    368 of 384 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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    335 of 361 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.

    Was this review helpful to you?  YesNo

    276 of 285 people found this review helpful

See all 618 customer reviews

Questions & Answers

Have a question about this product?
  
Sort Questions
Q
What is the chemical Tenacity?
A
Tenacity is a systemic preemergence and postemergence herbicide for the selective contact and residual control of weeds in turfgrasses. Tenacity contains the active ingredient Mesotrione.

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42 of 46 people found this answer helpful

Q
Do I need to keep the dogs away from the area where I have applied Tenacity?
A
You should keep the dogs off of the area while you are applying Tenacity and until the area has had a chance to dry, about 2-4 hours.

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802 of 823 people found this answer helpful

Q
Could you please confirm that Tenacity will not kill of Tall Fescue or any other grasses?

Is Tenacity available in Australia, Melbourne

A

Tenacity Herbicide is labeled for use on Tall Fescue, Kentucky Bluegrass, Centipedegrass, Buffalograss, Perennial Ryegrass, Fine Fescue, St. Augustine Grass. Other species of grass such as Bentgrass, Poa annua, kikuyugrass, zoysiagrass, seashore paspalum and bermudagrass are sensitive to Tenacity applications and damage may occur. According to the product label - Residential Lawn Applications: Unless renovating and/or re-seeding the home lawn, avoid broadcast applications of Tenacity for pre and post-emergence weed control because undesirable whitening of some turfgrasses may occur.

We do not ship to Australia and we are not sure if the manufacturer offers Tenacity in Australia. You can contact the manufacturer, Syngenta, to inquire about availability 866-796-4368.

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102 of 114 people found this answer helpful

Q
Can I use Tenacity on Buffalo and St. Augustine grass?
A
Tenacity is labeled for use in both St. Augustine grass and Buffalo grass. Be sure to read and follow the Tenacity product label for best results.

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24 of 30 people found this answer helpful

Q
After applying Tenacity and surfactant how long do you have to wait to seed or sod?
A
According to the Tenacity product label "Apply Tenacity at 5-8 fl. oz. per acre in at least 30 gallons of water per acre prior to seeding or post seeding of tolerant turfgrass species listed on this label, except fine fescue. Tenacity may reduce density of fine fescue seedings. Tenacity can be used on grass seed blends that contain less than 20% by weight of hard or fine fescue. Tenacity will control many monocot and dicot weeds that compete with and slow the establishment of the turfgrass stands. Apply at grass seeding or close to seeding for best performance. Avoid spraying on newly germinated turfgrass plants. Wait until the newly germinated turf has been mowed two times or four weeks after emergence (whichever is longer) before making a postemergence application." If you need more specific information on a turfgrass not mentioned on the product label you can reach the manufacturer at 866-796-4368.

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229 of 316 people found this answer helpful

Q
How much concentrated Tenacity do I need to cover one acre?
A
The instruction label for Tenacity calls for 5 to 8 ounces of Tenacity per Acre.  Please see page 8 of the product label for the amount per acre depending on the type of grass that you have.

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10 of 10 people found this answer helpful

Q
If Tenacity is applied to a pasture how long do you need to wait before allowing grazing?
A
We contacted the manufacturer Syngenta since Tenacity is not labeled for use on pasture land and they told us that you would need to wait 90 days before turning animals out to graze in treated pastures.

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42 of 45 people found this answer helpful

Q
Will Tenacity control Nutsedge grasses?
A
Tenacity is labeled for control of Yellow Nutsedge grass only. Tenacity does not cover other species of nutsedge. We do carry Sedgehammer which was specifically formulated for nutsedge control.

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56 of 58 people found this answer helpful

Q
How long should you wait before retreating your grass? It has been 2 weeks since I first applied. I can see

the sprayed areas are turning white. Should I do another application at this time. The "bad" weed is hanging in there and I want to totally get rid of it befor winter. Thanks

A
According to the Tenacity product label you can reapply the product after 2-3 weeks for post emergence control of actively growing weeds for best results.

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25 of 29 people found this answer helpful

Q
I am in Oregon with Green Perennial ryegrass. At what time of year do I start with my first application.

My personal lawn. Was hydroseeded and slowly has been invaded with crabgrass and other grassy weeds.

A
Timing will vary greatly from region to region. We recommend contacting your local cooperative extension office and speaking to the master gardener on staff as he/she will have the most accurate timing information available for your region.

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0 of 3 people found this answer helpful

Q
Does Tenacity kill Zoysia grass?

I'm looking for a product that will kill Zoysia grass.

A
According to the product label: Bentgrass, Poa annua, kikuyugrass, zoysiagrass, seashore paspalum and bermudagrass are sensitive to Tenacity applications. Avoid spraying these turf types unless control and/or injury can be tolerated. Maintain a five foot buffer between treated areas and bentgrass or Poa annua greens. While Tenacity is not labeled to kill zoysia it will most likely do so.

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110 of 123 people found this answer helpful

Q
Does Tenacity control Quackgrass?

I know quackgrass is not specifically mentioned on the product label, but I have read some unscientific research saying it does control and eliminate quackgrass with repeated applications.

A
Just as you stated Quackgrass is not on the label to be controlled by the Tenacity, and we cannot recommend you use it for your needs with it not being listed. We do however carry Certainty, which is a selective post emergent herbicide like Tenacity, and does have Quackgrass listed on the label for weeds controlled. You can see the dilutions and what grasses Certainty is safe to be used on, on the product label.

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10 of 14 people found this answer helpful

Q
I have crab and quack grass among perennial plants such as day lilies, will Tenacity work?
A
Tenacity is not labeled to kill Quackgrass. We recommend using a glyphosate product like Glyphosel Pro and spot treating. You can also use a product a selective herbicide like Certainty if you have warm season grass. Please make sure to always review the product label to make sure you are using the right product and mixing ratio for your needs.

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6 of 7 people found this answer helpful

Q
Which pre- emergent is best for control of nutsedge

Every year i have problem with nutsedge weed. Can you suggest which pre- emergent is best to use.

A
Nut sedge is a summer weed that is hard to control using a pre emergent. A great post emergent to ponder over is called Sedgehammer. SedgeHammer herbicide kills nutsedge without injury to turfgrass, established ornamentals, shrubs, and/or trees. SedgeHammer provides post-emergence control of both purple nutsedge and yellow nutsedge. SedgeHammer also controls many broadleaf weeds and suppresses kyllinga. Nutsedge is controlled after emergence in cool and warm season turf grasses such as St. Augustinegrass, Bermudagrass, Kentucky Bluegrass, tall and fine fescue, and perennial ryegrass. Sedgehammer is considered one of the more "gentle to turfgrass" products and pets and people can return to the treated area once the spray dries.

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50 of 55 people found this answer helpful

Q
How long do I need to wait to start bagging my lawn for composting the clippings.

I heard the product stays active even after composting and may harm my garden plants.

A
We contacted Syngenta which is the manufacturer of the product. According to Syngenta, once you have cut your grass, you would need to put the clipping in the compost pile and let it sit for at least 30 days. After 30 days the chemical has broken down in the clippings and can be used in other areas of the yard where you are growing garden plants.

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190 of 205 people found this answer helpful

See all 678 customer questions

Tenacity Herbicide 4.5 out of 5 stars Rating: 4.3 (618 Reviews / 678 Q&A)

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