Tenacity is a systemic pre-emergence and post-emergence herbicide for the selective contact and residual control of weeds in turfgrasses. 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, susceptible weeds absorb Tenacity 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 postemergence applications.
|Active Ingredient:||Mesotrione - 40%|
|Target pests:||Barnyardgrass, Carpetweed, Chickweed, Clover, Crabgrass (large & smooth), Dandelion, Foxtail, Goosegrass, Henbit, 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 |
|Application:||4 - 8 oz. per 30 gallons of water per acre |
* See label for complete application instructions
|Formulation:||Professional Product |
Group 27 Herbicide
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.
See all 44 reviews »
40 of 43 people found this review helpful:
By Frank in Johnston, IA on May 7, 2012
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.
31 of 31 people found this review helpful:
A Miracle Herbicide!
By Margaret in Scarsdale, NY on August 14, 2012
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.
23 of 25 people found this review helpful:
Appears to be working!!!!!!!!!!!!
By Del in Decatur, IL on June 17, 2012
I was skeptical about whether Tenacity could kill the Nimblewill in my lawn and still leave my Blue Grass and Fescue alone. It's been 2 weeks since the first application and it appears to have definitely wounded the Nimblewill. The second application was applied yesterday, so we'll see if it kills it or not. It's a "pricey" chemical, but is easy to use and hopefully effective. If it works it sure beats Roundup and reseeding.
23 of 26 people found this review helpful:
Great product! Does exactly what it advertises!
By Debi in Toledo, Ohio on September 7, 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?
19 of 19 people found this review helpful:
No more Crabgrass!!
By Rob in Greeley, Colorado on August 23, 2012
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.
By Shane in Lexington, N on April 25, 2015
Tenacity is excellent stuff! While most standard herbicides at the big box stores will take care of the easier to kill weeds Tenacity will get rid of the tougher ones. It really did a number on poa annua and crabgrass in my lawn with no permanent damage to the turf. I did get a little bleaching in my tall fescue but the color came back and all is well. Don't expect overnight results. Tenacity takes nearly 2 weeks to show visible results. Haven't used it as a pre-emergent yet but plan to this fall during my overseed.
Good cool season product
By Jeff in Madison, WI on April 22, 2015
This product has done a great job of knocking down some very tough weeds in my Kentucky Bluegrass turf. Waiting to see how the residual controls as a pre-emergent as the weather warms up.
1 of 1 people found this review helpful:
My first experience with Tenacity.
By Roger in Chattanooga, Tennessee on April 18, 2015
I had plenty of rain in the week after Tenacity application. Within 5 to 7 days the weeds, including crabgrass, buffalo grass, clover and other broad leaf plants began to turn yellow and then white, and die. Where the application was heavier the color change was more dramatic. I seeded with fresh good quality seed, a blend of the new varieties of K-31 and other cool season home turf grasses. As of 16 days I have very little new grass appearing in my yard. It has been a wet spring in Chattanooga,therefore water is not the problem. I am beginning to wonder if the claim that you can apply Tenacity and seed all in the same day of two is really true. I hope so; the seed costs me almost $1,000. If the grass seed does pop up I will be sure to add that to this note. As a herbicide, it seems to be doing well. I am going to wait to apply the second application of Tenacity until I see what the grass seed really does do.
4 of 4 people found this review helpful:
Never ending battle of Bentgrass
By Kathy in Buffalo NY on October 23, 2014
I heard so many great things about Tenacity that I needed to try it to remove my lawn of bentgrass. This is my 3rd application and I still have bentgrass. It does work but expect at least 6 weeks of an unsightly lawn with each application. You will also have to keep reapplying it so your lawn will look unsightly again. Also it is costly but you only need 1/2 teas per gallon of wate.r Could be because of the amount od bentgrass that I have but I wish it would work quicker and more effectively. One plus, is that it does not damage the good turf.
2 of 2 people found this review helpful:
Worked as Expected
By Mike in Shelton, Washington on October 20, 2014
This is a product I have been looking for to control my poa annua and creeping bentgrass. After I treated it took awhile, but sure enough my weeds stared turning a whitish color. It took a couple weeks to start seeing results so you have to be patient. I have just applied a second treatment and can't wait for next spring to see final results.
4 of 5 people found this review helpful:
Tenacity Kicks Nimblewill Butt
By Greg in VA on October 8, 2014
Even the small container of the selective herbicide goes a long way for spot weed control as you use a miniscule amount of product, via the included syringe, for a pump sprayer. One needs patience as it takes an application, then another a couple of weeks later, for the nimblewill / nimbleweed to turn color. it will also turn neighboring grasses white as well, yet they will grow out according to the instructions. I am about to start re-seeding the thick areas of weed that will now pull out easily as it is dead.
1 of 1 people found this review helpful:
By Marty in Hempstead, N.Y. on October 7, 2014
Within the first two weeks, I noticed that some grass was turning white, which, according to the instructions, was supposed to happen. The net grass is still brown, and I am hoping after the second treatment, which was done a couple of days ago, will do the trick. I bought the product specifically for bent grass, and I hope that it works.
4 of 4 people found this review helpful:
Nimble weed control
By Bem in OH on October 5, 2014
Put it down at half strength to control nimble weed. It appears to be killing nimble weed but the tall fescue doesn't look so good as well. Everything turning white, Hopefully grass will come back
2 of 2 people found this review helpful:
By Chevo in Burke, VA. on September 29, 2014
I purchased and used the Tenacity Herbicide for my 1 acre lawn and followed the directions provided by mixing 1 tsp per gallon of water and adding surfactant. First, the price at DoMyOwnPestControl was the cheapest. My local nursery in Northern Virginia tried selling me the same product for twice the price. Second, I chose this product as recommended by my local nursery because the Ortho Crabgrass Killer spray bottle, which attaches to my water hose had not worked 1 month prior. Third, after using the product, I noticed that the crabgrass and other weeds started to eventually turn white; then died. Within 2 weeks of using the product, I mowed my lawn, dethatched, core-aerated, oversed, and topdressed. Therefore, it is too early for me to determine how long it's effects will last. Overall, I will rate this at 4 out of 5 stars. It is a great product, does the job, is certainly cheaper at this website. The remaining star is what remains to be seen in the future...
3 of 3 people found this review helpful:
Works great to remove bentgrass
By JP in Central Indiana on September 24, 2014
I had a large section (about 4,000 sq. ft.) of Kentucky bluegrass/fescue/perennial rye lawn which had long been seriously infested with creeping bentgrass, as well as some bermudagrass or nimblewill (I can't tell the difference between them) and wild violet. I used 2 applications (at the label recommended rate) of Tenacity, 10 days apart, starting the first week of September. I applied as a spot spray with a backpack sprayer. A week after the second application, I did indeed have large patches of white lawn. 10 days after the second application, The bentgrass appears to be completely dead, and the lawn grasses appear to be slowly recoloring. The Tenacity had little to no affect on the wild violets or the bermuda/nimblewill. It did nail a few plaintains, dandelions and some crabgrass. Since it's late in the season, I'll go back to hitting the wild violets and bermuda/nimblewill with Acclaim/Triclopyr, which does work well in a single application. Although the Tenacity is quite expensive, I've never seen anything else work like this on bentgrass. DMOPC.com's price for Tenacity was less than half the price from my local retail supplier. Along with that, a little of this product goes a very long way.
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August 9, 2011
William from Springfield, Il. asked:
QHow much Tenacity do you mix in a one gallon sprayer?
June 14, 2013
Gregg from Hastings Ne asked:
QApplication tips for Tenacity
I wish to apply Tenacity with a hand sprayer. Do you have any application tips? Would broadcast application be better than spot spraying? If spot spraying, how much should I apply?
A According to the Tenacity product label for smaller applications you will need to mix 0.5 tsp of Tenacity, 1.5 tsp of surfactant to one gallon of water and each gallon of solution needs to cover 1,000 sq ft. Broadcast treatments would be recommended if you are needing to actually treat the entire lawn for pre-emergence, if you are only needing to treat small areas or use as a post emergent then you can spot treat.
According to the Tenacity product label for smaller applications you will need to mix 0.5 tsp of Tenacity, 1.5 tsp of surfactant to one gallon of water and each gallon of solution needs to cover 1,000 sq ft.
Broadcast treatments would be recommended if you are needing to actually treat the entire lawn for pre-emergence, if you are only needing to treat small areas or use as a post emergent then you can spot treat.
October 11, 2011
Mary from Marshfield, Wi asked:
QDo I need to keep the dogs away from the area where I have applied Tenacity?
AYou 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.
March 8, 2012
Scott from Grosse Ile Michigan asked:
QAfter applying Tenacity and surfactant how long do you have to wait to seed or sod?
AAccording 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.
January 15, 2012
Lea from Melbourne, Victoria, Australia asked:
QCould 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.
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.
May 16, 2015
W. from Western Massachusetts asked:
QShould grass clippings be bagged after tenacity application, or left on lawn with mulching mower for 1st cut?
It would be best if clipping were bagged after first mow and applicaion of
Tenacity Herbicide. Bagging will also help with lawn health.
May 13, 2015
Walter from Attleboro Ma 02703 asked:
QWhat is the best product to get rid of poa annua in my lawn?
new lawn loaded with poa now seed heads everywhere I also do have some issues with bent grass I have used tenacity for it is the a product to control the poa annua pre or post apps spring and fall to kill and control?????
A Tenacity Herbicide is labeled for both pre and post emergent control of selective weeds. The label specifically states that bentgrass and poa annua are sensitive to this product and will likely kill it. With poa annua, it is labeled for pre-emergent control only. Tenacity will kill bent grass both pre and post emergently.
May 10, 2015
Jeffrey from Trumbull asked:
QWill Tenacity damage Poa trivialis lawngrass?
I have Poa Triv in shady areas and need to get rid of invasive creeping bent in my lawn.
A The product label for Tenacity does not specify whether it would harm poa trivialis. Both bentgrass and poa annua may be sensitive to Tenacity, while Kentucky Bluegrass is listed as tolerant. Certainty Herbicide is labeled to control poa trivialis, but we are not certain if it would harm the bentgrass. The best option for you is to spot treat the rough bluegrass with RoundUp QuickPro and then reseed with the desirable turfgrass.
May 8, 2015
J. from Sewickley, Pa asked:
QDoes Tenacity work on Nimbleweed?
A Tenacity is labeled for post-emergent control of Nimbleweed. Per the product label, you may need a second application after 2 to 3 weeks. Apply to young, actively growing weeds, and be sure to use a surfactant such as Southern Ag Non-Ionic surfactant for post-emergent applications.
May 4, 2015
Jim from Fort Morgan, Co asked:
QIn one answer about watering you state it does not need to be watered in because it is mixed with water;
however, in another answer you state it does, indeed need to be watered in asap. could you please clarify which is correct. Thank you.
A Tenacity is a systemic preemergence and postemergence herbicide for the selective contact and residual control of weeds in turfgrasses. When applied as a preemergent, weeds absorb Tenacity during emergence from the soil. Dry conditions following application may reduce the preemergence activity. If rainfall (0.15 inches) has not occurred within 10 days after a preemergence application, activate with 0.15 inches of irrigation. When used as a postemergent, susceptible weeds absorb Tenacity through foliar contact and soil absorption. Therefore, you should water in Tenacity when using it as a preemergent herbicide but it does not need to be watered in when using it as a postemergent herbicide.
April 25, 2015
Mark from Southington, Ct asked:
QWhat is the shelf-life of Tenacity Herbicide?
I plan to use this for spot treatments on small areas of bentgrass. Using only 1/2tsp per gallon, an 8oz bottle is going to last me at least a few years. What is the shelf-life of this product?
A If stored in a cool dry area, Tenacity Herbicide will last up to 3 years.
April 21, 2015 Wayne asked:
QHow soon can I mow my lawn after an application of Tenacity?
A You can mow your lawn 2 days before application of Tenacity Herbicide and two day after application.
April 14, 2015 Donald asked:
QWhy doesn't Tenacity ship to CA?
A There are EPA regulations in each state that state which products can be shipped to a particular state. Some products do not obtain registration in certain states. We apologize for any inconvenience this may cause.
April 13, 2015
Jim from Northern Virginia asked:
QI have what a landscape person called Rough Stalk Bluegrass, a Canadian Hybrid or Poa Trivilais.
There are patches in my yard that have a bright greenish color. It really stands out. Will Tenacity take care of this.
February 11, 2015
Maria from Portland, Or asked:
QThe bentgrass is gone. How often do I need to spray Tenacity to keep the bentgrass out?
I don't want the bentgrass to come back. Please let me know at what interval I should spray Tenacity.
We apologize but there is not an exact time frame of how often you should apply the Tenacity Herbicide to keep the bentgrass out of your lawn. The product label states that the Tenacity acts as a pre and post emergent on bentgrass so it should help prevent it for at least a few months if you sprayed recently as a spring application. Post emergent wise, you would apply it as you start to see new signs of bentgrass growth to eliminate it as its come up at that point. Tenacity is a strong product so you dont want to over apply the product and risk harming/burning your lawn or whiten it too much. You could easily apply it every 3 or 4 monts and should be fine however per the product label regarding treating for bentgrass it states: Control of bentgrass (Agrostis spp.) and nimblewill (Muhlenbergia schreberi) – Apply Tenacity at 5 fl. oz. per acre in at least 30 gallons of water per acre at two to three week interval for up to three applications. Apply with a NIS surfactant. Bentgrass control may be more effective in the late summer/early fall just prior to onset of renewed bentgrass growth, than spring/early summer applications.
We apologize but there is not an exact time frame of how often you should apply the Tenacity Herbicide to keep the bentgrass out of your lawn. The product label states that the Tenacity acts as a pre and post emergent on bentgrass so it should help prevent it for at least a few months if you sprayed recently as a spring application. Post emergent wise, you would apply it as you start to see new signs of bentgrass growth to eliminate it as its come up at that point. Tenacity is a strong product so you dont want to over apply the product and risk harming/burning your lawn or whiten it too much. You could easily apply it every 3 or 4 monts and should be fine however per the product label regarding treating for bentgrass it states:
Control of bentgrass (Agrostis spp.) and nimblewill (Muhlenbergia schreberi) – Apply Tenacity at 5 fl. oz. per acre in at least 30 gallons of water per acre at two to three week interval for up to three applications. Apply with a NIS surfactant. Bentgrass control may be more effective in the late summer/early fall just prior to onset of renewed bentgrass growth, than spring/early summer applications.