Tenacity is a systemic preemergence and postemergence herbicide for the selective contact and residual control of weeds in turfgrasses. When applied preemergence, 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 postemergence, 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 postemergence weed control. A non-ionic surfactant should be added in postemergence applications.
|Active Ingredient:||Mesotrione 40%|
|For use in:||Kentucky Bluegrass, Centipedegrass, Buffalograss, Tall Fescue, Perennial Ryegrass, Fine Fescue, St. Augustine Grass|
|Coverage Area:||5 to 8 fluid ounces per acre|
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.
What is the active ingredient in Tenacity herbicide?
Mesotrione is the active ingredient in Tenacity herbicide.
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 turf species can Tenacity be applied to?
Tenacity can be applied to many of the cool-season turf types commonly found on fairways and roughs, such as Kentucky bluegrass, perennial ryegrass, tall fescue, fine fescue, centipedegrass, and St. Augustinegrass (sod only). Lower use rates are recommended for perennial ryegrass, fine fescue, and St. Augustinegrass. Tenacity is not for use on putting greens and tees.
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 37 reviews »
33 of 35 people found this review helpful:
By Frank 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.
23 of 23 people found this review helpful:
A Miracle Herbicide!
By Margaret 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.
19 of 21 people found this review helpful:
Appears to be working!!!!!!!!!!!!
By Del 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.
16 of 19 people found this review helpful:
Great product! Does exactly what it advertises!
By Debi 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?
15 of 15 people found this review helpful:
No more Crabgrass!!
By Rob 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.
Nimble weed control
By Bem 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
By Chevo 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...
Works great to remove bentgrass
By JP 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.
By Ken on September 23, 2014
I've used Tenacity for a couple of years. It's a good product. Very safe and easy to use. Best of all, it works on Bermuda grass and Nutsedge without damaging the regular grass. It can also be used in conjunction with overseeding or new seeding. For larger areas, I use Trimec since it is less costly per gallon, but for spot spraying and Bermuda, Tenacity is the most effective. Too, the price from domyownpest.com was the best I found.
1 of 1 people found this review helpful:
By Kathy on September 13, 2014
I purchased an 8 oz bottle of Tenacity to control the nimblewill that is beginning to take over my yard. I applied it according to instructions, and it has begun to show results after about i week.
0 of 2 people found this review helpful:
Only works temporarily
By Gary on September 10, 2014
It did work as advertised but the bentgrass came right back 100% in the same spots within 30 days. This product was applied professionally for two applications.
Tenacity for Chickweed
By Skip on September 9, 2014
I bought for Chickweed control and fall Chickweed pre-emergence. Will not see results until the Spring. On the plus side it has turned quite a few of the other weeds/grasses in my yard white. I just hope they die and do not come back. I used in a 2 gallon sprayer with non-ionic surfactant and a marking solution. Takes awhile to do the whole yard but well worth it if it controls the weeds and germination seeds better than the big store brands - Scxxts etc... I will re-apply in mid March and try for pre-emergence control of anything I might have missed.
So Far So Good
By Rick on September 8, 2014
I just put down my second application and so far I am very impressed. I'm putting it down with a 2 gal. tank sprayer. It has "done a number" on my bent grass and that is what I was primarily after. As a bonus, it is also wiping out my wild violets. I have been trying to kill those for about 10 years. I'm anxious to see what things look like in the spring. Has this really eliminated the patches of bent grass (and violets) or are they coming back in the spring?!?
Works as advertized
By Jerry on August 26, 2014
I used this product 4 weeks ago to some of my problem areas as far as crabgrass, creeping charlie and nutgrass. It did the job! Make sure you follow the directions as far as the 1 teaspoon per two gallons though. My first batch I did not measure and it took awhile for the grass to bounce back. Definitely turns the weeds white but don't worry it bounces back.
This is an incredible herbicide
By Barry on August 23, 2014
I applied this a week ago to creeping bent-grass and an occasional clump of crabgrass. As promised, the grasses are turning white. I'm sorely tempted to reapply after a week but will wait one more for the second application. And for those who note how expensive this is, it's a dollar an application for 2 gallons of spray ... compare that with other herbicides.. and it's low toxicity makes it a winner...
Have a question about this product?
Ask our product experts...
Ask a Question
August 9, 2011
William from Springfield, Il. asked:
QHow much Tenacity do you mix in a one gallon sprayer?
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.
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.
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.
October 22, 2014 Steven asked:
QWill Tenacity Herbicide effect insects in the target area?
A Tenacity Herbicide will not affect insects in the area that has been treated. It is a reduced risk herbicide. According to the manufacturer, Tenacity Herbicide should is not recommended to spray while bees are foraging.
October 12, 2014
Maria from Portland, Oregon asked:
QHow often do I apply Tenacity to healthy lawn to keep the bentgrass out?
I have killed the Bentgrass with Tenacity and reseeded. New grass is now growing in those areas. It is mid-October in NW Oregon. How often should I apply Tenacity to prevent the Bentgrass from coming back?
A You can reapply Tenacity Herbicide when the newly germinated turf has been mowed two to three times or four weeks after emergence, which is longer. Repeat applications can be done after two to three weeks for continued post emergent weed control.
October 3, 2014 Steven asked:
QWill Tenacity work on Nutsedge growing in my Oporum ground cover?
A Tenacity is a systemic preemergent labeled to treat for Yellow Nutsedge only, but not does list other types of nutsedge. We do carry Sedgehammer, a post emergent which is labeled for Purple and Yellow Nutsedge control. We recommend contacting your local Master Gardner for clarification on the effects of either of the products on you oporum ground cover.
September 4, 2014
Brenda from Port Hope, Mi asked:
QWhat product do you recommend to kill Creeping Charlie in our lawn?
I do want a product that is not harmful to our lawn grass. Thank you
Tenacity is labled to control Ground Ivy "Creeping Charlie" as post emergent control. We highly recommend using a temporary turf colorant like Turf Mark Blue so that you can see where you spray with the Tenacity to avoid overlapping. Tenacity is a great product, but also a very strong product so too much overlapping or mixing the product too strong can cause temporary damage and whitening to your turf around the ground ivy. The color will come back in the lawn after 3-4 weeks but to avoid this potential problem it is best to use a colorant to make sure no overlap occurs. To get optimum results for post emergent control it is recommended you use a Non Ionic Surfactant in your mixture as well. Please be sure to find out what type of turf you have and review the product label to make sure your turf is tolerant to this product.
September 4, 2014
Leo from Narragansett,ri asked:
QWhat effect does Tenacity have on Barletta pear trees
September 1, 2014
Nancy from Oriskany,ny asked:
QHow soon can I mow the lawn after applying Tenacity?
A According to the Tenacity product label for New Lawn Establishment: 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 it is an established lawn, we recommend waiting to mow your lawn 5-7 days after application and 2-3 days prior to application.
August 11, 2014
Wayne from West Salem, Wi asked:
QIs Tenacity safe to use around trees and shrubs?
August 11, 2014
Grant from Groton, Sd asked:
QWill Tenacity kill seedling trees?
I have a newly planted tree grove (last year) and there are many growing broadeaf weeds that are taking over.
A Tenacity Herbicide is not labeled for trees so spraying around the trees could possibly harm them. We would recommend contacting the manufacturer directly for instructions on spraying around new trees. Here is the number: 866-796-4368.
July 27, 2014
Steve from Pleasantville, Oh asked:
QWill Tenacity affect all varieties of Poa?
I have what I believe is Poa but am not certain of the variety (annua or other). How can I determine what I have?
Tenacity Herbicide treats for Poa Annua and should cover other varieties. We recommend to contact your Cooperative Extension Office and speak with the Master Gardener to identify the weed species you need to treat for.
July 22, 2014
Jim from Fort Morgan, Co asked:
QDo you need to water in Tenacity?
In an answer it says that you can water right away. Could you please clarify your statements? I will use it as a post-emergence application. Thank you for your assistance
A Tenacity Herbicide does need to be mixed with water when it is applied. You can water the lawn after it has been applied, but it is not necessary due to the product being mixed with water when applying. Please let us know if you have any additional questions.