Using Tenacity Weed Killer for Lawn Control and Maintenance

Kenneth Wilson

If you're currently browsing for effective weed killers, the Tenacity weed killer is an excellent option to eliminate pesky weeds on your lawn. It is a highly-effective weed control choice that's popular among many homeowners in the country, as it is proven effective in removing a variety of problem weeds: crabgrass, clover, foxtail, henbit, and nutsedge.

The Tenacity herbicide can be applied to existing seeding weeds and can also provide weed control to protect your established turfgrass from weed infestation. Since it is safe to use as a pre-and post-emergent, it can control up to 46 common lawn weed and grass species and is EPA-classified as a "reduced risk," given it is naturally derived from the Bottlebrush Plant.

Tenacity Lawn Weed Killer Product Overview

The Tenacity weed killer is manufactured by Syngenta Turf & Landscape, formulated to control more than 46 broadleaf and grassy weed species.

It has 40% of the active ingredient Mesotrione, naturally produced by the bottlebrush plant (Callistemon citrinus). This prevents weeds from conducting photosynthesis– disabling them from thriving. As previously mentioned, it can be used for pre-and post-emergence control of stubborn lawn weed species. (Related: 10 of the Best Crabgrass Killers That Won’t Kill Your Healthy Grass)

Key features and benefits:

  • It is safe to use for post-emergent control
  • It removes creeping bentgrass from approaches
  • This product is ideal for renovation projects
  • Eliminates weeds during seeding so your new grass can flourish
  • It effectively controls common lawn weeds such as crabgrass, ground ivy, nimblewill, and yellow foxtail

What Weeds does Tenacity Kill?

The Tenacity lawn weed killer is proven to be effective on more than 46 common broadleaf weed and grass species:

Annual Bluegrass
Buckhorn Plantain
Canada Thistle
Catsear Dandelion
Common Chickweed
Common Dandelion
Common Lambsquarter
Common Purslane
Creeping Bentgrass
Curly Dock
Florida Betony
Florida Pusley

Ground Ivy
Large Crabgrass
Large Hop Clover
Lawn Burend
Mouseear Chickweed
Pale Smartweed
Pennsylvania Smartweed
Persian Speedwell
Purslane Speedwell
Redroot Pigweed

Shepherd’s Purse
Smooth Crabgrass
Smooth Pigweed
Southern Crabgrass
Tufted Lovegrass
White Clover
Wild Carrot
Wild Violet
Windmill grass
Yellow Foxtail
Yellow Nutsedge

How to Use Tenacity to Kill Weeds

Using Tenacity herbicide to eliminate pesky weeds involves a pressurized hydraulic sprayer, a high-volume handgun or pump sprayer, or a backpack sprayer.

  • Step 1: First, determine the total square footage of the lawn area you want to treat. This will tell you how much Tenacity weed killer you need to apply for lawn treatment. It also involves determining the specific weed species on your turf. You can apply 4 to 8 fluid ounces per 30 gallons of water per acre for large lawns. If you only want to do spot treatments or have a small yard at home, half a teaspoon of Tenacity in 1 gallon of water is enough to cover 1,000 square feet.
  • Step 2: The next step involves creating the Tenacity weed killer solution. Fill half of the spray tank with water before adding the recommended amount of Tenacity weed killer. Secure the sprayer with a cap and shake the mixture well.
  • Step 3: Now that your Tenacity solution is ready to use, apply the herbicide to the infested areas of your lawn. Ensure not to overapply the mixture to the point of runoff. To ensure even coverage, use a fan-spray nozzle setting. You can repeat the application for the best results after 2 to 3 weeks. One bottle of Tenacity weed killer (8 oz.) is enough to cover 1 to 2 acres of your property after mixing it with 30 gallons of water for each acre. Every purchase will also come with a syringe designed for spot treatment purposes.

Pre-emergent Applications

For pre-emergent applications, apply Tenacity weed killer at 4 to 8  fl. oz. per acre (with 30 gallons of water per acre) before the weed seed germination.

Avoid exceeding five fl. oz. per acre to fine fescues or perennial ryegrass and four fl. oz. per acre to St. Augustinegrass turfgrass. Ensure the application is scheduled close to the regular weed seed germination.

Post-emergent Applications

For post-emergent applications, apply Tenacity weed killer at the same rate as pre-emergent applications at 4 to 8 fl. oz. per acre (in at least 30 gallons of water for each acre). You can apply this with a non-ionic surfactant, such as the Hi-Yield Surfactant. Experts recommend using surfactants with Tenacity to improve its effectiveness by allowing the herbicide to penetrate the soil better and kill weeds efficiently. Ideally, repeat the application after two to three weeks.

Key Considerations When Using Tenacity Weed Killer

Tenacity herbicide is designed to kill existing weeds immediately after application, but you will only notice a significant difference after two to three weeks. Some weed species may also require a follow-up application to ensure the best results.

Always read the product label carefully before starting the lawn treatment process. Avoid excessive use of the product– as it may result in a temporary burn or loss of color in your turfgrass. In some cases, it may also cause some foliage to turn white. These symptoms are noticeable sometime between five to seven days after application and may drag on for several weeks at a given time.

Frequently Asked Questions (FAQs)

What is Tenacity Herbicide?

Syngenta-manufactured Tenacity weed killer is considered one of the most effective and safe weedkillers sold on the market. Weeds, including nutsedge, crabgrass, clover, dandelions, and many others, can be exterminated by it effectively even before they sprout (pre-emergent control) or even after weed patches appear on your lawn (post-emergent).

Is Tenacity Herbicide safe for use around children and pets?

Tenacity Herbicide is completely safe and non-toxic for children and animals after it dries on your lawn. Mesotrione, a sulfur compound taken from the bottlebrush plant, is this weedkiller's active ingredient. Environmental Protection Agency has granted Tenacity a "reduce risk" status, and their product does not contain any cancer-causing substance.

How long does it take for Tenacity to work?

Tenacity will begin to take effect after a few days. You will start to see the weed's green color fade, and they will eventually die. It is highly suggested by the manufacturer to leave the weeds and let them compost naturally. If persistent weeds exist, a second treatment must be done around three weeks after the first application. It is also best to plant grass seeds during the second Tenacity treatment. You must wait about three weeks to conduct the third treatment for extremely stubborn weeds.

When is it best to apply Tenacity herbicide?

Spring and fall are the best times to use this herbicide on a dry lawn. Also, make sure that the air temperature is not higher than 80 degrees during the time of application. Pets and children are welcome to play on the grass after two hours of drying. Once it is dry, rain and an increase in temperature will no longer affect the herbicide's effectiveness.

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

Using Tenacity on grasses such as zoysiagrass, seashore paspalum, Kikuyu grass, and hybrid or common Bermuda grass is not recommended.

What makes Tenacity different than other currently used turf herbicides?

Tenacity is a selective and systematic herbicide that utilizes different modes of action for pre- and post-emergent grass and controls broadleaf weed in various warm- and cool-season turf species. Established and freshly seeded labeled turfgrass species can also be applied with Tenacity.

What is the active ingredient in Tenacity herbicide?

The active ingredient that can be found in Tenacity herbicide is called Mesotrione.

What are some of the unique benefits of Tenacity herbicide?

Tenacity affects 46 dicot and monocot weed species through pre- and post-emergence activity. It can selectively suppress annuals like crabgrass, goosegrass, and perennial monocots like bentgrass and nimblewill. Apply Tenacity at the seeding to stop the weed from germinating while establishing turfgrass species without weed competition.

Kenneth Wilson
July 18, 2022
2terra, Reviews, Yard & Garden

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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