Tenacity Herbicide, produced by Syngenta, has become one of the most talked-about solutions for weed control in cool-season lawns. With its unique ability to act as both a pre- and post-emergent herbicide, it effectively eliminates crabgrass, clover, and other weeds while remaining safe for grass seeds and overseeding applications.
This review, we’ll share real-world results, highlight application tips, and explain why Tenacity has earned a reputation as a miracle herbicide for many lawn enthusiasts.
What Is Tenacity Herbicide?
Tenacity Herbicide contains the active ingredient mesotrione, which inhibits photosynthesis in weeds, causing them to bleach and die. It targets over 40 broadleaf and grassy weeds, making it versatile for controlling difficult-to-kill plants like bentgrass and crabgrass.
Key Features:
- Acts as both a pre-emergent and post-emergent herbicide.
- Safe for new grass seed and overseeding.
- Controls weeds without harming good grass.
- Targets crabgrass, dandelions, clover, and more.
Tenacity Herbicide Application Rates
Pre-Emergent Application:
- Mix 1/2 teaspoon of Tenacity with 1 gallon of water to cover 1,000 sq. ft.
- Water lightly within 1–2 days to activate.
Post-Emergent Application:
- Mix 1/2 teaspoon of Tenacity with 1 1/2 teaspoons of non-ionic surfactant (NIS) in 1 gallon of water for spot treatment.
- Repeat applications 10–14 days apart for tougher weeds.
How to Apply Tenacity Herbicide
- Prepare Your Equipment: Use a hand sprayer or backpack sprayer for even application.
- Mix Properly: Follow the recommended rates and add blue dye to track sprayed areas.
- Apply Evenly: Spray lightly over the lawn or target spot treatments for specific weeds.
- Water In (Pre-Emergent Only): Apply light irrigation within 24–48 hours for maximum effect.
- Monitor Progress: Expect bleaching of treated weeds within 5–7 days.
Real Results – Tenacity Herbicide Experiment
We applied Tenacity Herbicide in August to combat a creeping bentgrass infestation after dethatching and core aeration. Despite bleaching and temporary discoloration concerns, the treated areas significantly improved after two applications spaced 10 days apart.
Expanded Experience – Professional Use with Torocity (Generic Tenacity)
I also used Torocity, the generic version of Tenacity, professionally for a customer battling a severe bentgrass problem. After performing multiple post-emergent spot treatments, the results were excellent. The bentgrass showed signs of bleaching within 5–7 days; by 14–21 days, it was significantly weakened. Two treatments eliminated the problem, leaving the customer’s lawn healthier and ready for overseeding.
This experience further solidified mesotrione-based herbicides as a go-to solution for personal and professional lawn care projects.
Pros and Cons of Tenacity Herbicide
Pros:
- Pre- and Post-Emergent Control: Targets weeds at all growth stages.
- Safe for Overseeding: Does not affect new grass growth.
- Versatile Use: Effective against crabgrass, clover, and bentgrass.
- Long-Lasting Effects: Provides 30 days of pre-emergent control.
Cons:
- Temporary Bleaching: Can discolor good grass temporarily.
- Multiple Applications Needed: Stubborn weeds may require two or more treatments.
- Higher Price Point: More expensive than standard weed killers.
Frequently Asked Questions (FAQs)
When should you NOT spray Tenacity?
Avoid applying Tenacity when temperatures exceed 85°F, during drought, or within 2 weeks of reseeding or aerating.
Does Tenacity Herbicide really work?
Yes, Tenacity is highly effective when applied correctly, especially on cool-season grasses. It controls crabgrass, dandelions, and bentgrass, delivering visible results within 1–2 weeks.
What happens if you use too much Tenacity?
Overuse may cause prolonged bleaching of desirable grasses. Always follow label instructions to avoid damage.
Is there something better than Tenacity?
While Tenacity works well, Drive XLR8 is often preferred for mature crabgrass, and Prodiamine may provide longer-lasting pre-emergent control.
Final Thoughts – Is Tenacity Worth It?
Tenacity Herbicide stands out as a miracle herbicide for tackling stubborn weeds without harming good cool-season grasses. Whether you’re battling crabgrass, bentgrass, or clover, this post-emergent weed killer delivers excellent results when used correctly.
While it requires multiple applications and may cause temporary discoloration, its ability to work as both a pre-emergent and post-emergent herbicide makes it a must-have tool for any lawn care arsenal.
Ready to transform your lawn? Try Tenacity Herbicide today and experience the difference!
More questions? Check out our huge Tenacity herbicide FAQ guide.
I’ve had great success with removing bentgrass with Tenacity, so much so that I made my only YouTube video of the process for others to see. I was thinking of using my Tenacity as post-emergent weed control. I was going to do a blanket spray on my lawn to just kill off anything existing or anything that is starting to emerge. I also ordered the new kelp4less green lawn mix. Do you think it would be fine to mix the kelp4less with Tenacity and do a blanket spray? Then I can kill two birds with one stone.
Hi Dan! Thanks for the comment. Your video, in fact, helped me pull the trigger in doing this to my lawn. Awesome content! I think you could mix them together if you were to use Tenacity as a pre-emergent. But if it’s a post emergent killer, then no – only because you need a Non-Ionic Surfactant (NIS) for this method. I’d probably to two separate apps in this case.
Hi,
I’ve been following your website for about a year now and really appreciate the strategies, tips and schedules you’ve provided. Thanks for making this available.
I have a question about what I should do for the next several weeks. I saw POA in my yard during the spring this year, and I’ve recently found creeping bent grass in several spots. I’m planning to put the first application of Tenacity down this week. I just wanted to clarify that I will need to use the post-emergent application process (including NIS) for this application.
I then plan to dethatch, aerate and overseed per your suggested schedule in early September. Should my second application of Tenacity line up with when I overseed? And if so, should I use the pre-emergent application process at this point (ie. not including a NIS)?
Last question – I’ve heard that Tenacity as a pre-emergent, only lasts 30 days. So should I put down prodiamine at some point this fall or should I wait until April for the first application? Whew. Ok, I think that’s it.
Thanks again for your help!
Abby
**Also, I attempted to contact you through your “contact” page, but the reCAPTCHA “I’m not a robot” part wouldn’t load.
Hi Abby,
Thanks for the following! I appreciate the support.
When you apply Tenacity as a pre-emergent, you will not need NIS; and should be watered in with 1/4″ of water. This can be done at the same time of seeding. It’d be a good idea to apply a second post emergent of Tenacity herbicide to kill bentgrass.
Unfortunately you cannot apply Prodiamine until next year. New grass needs time to establish deeper, stronger roots. However the Tenacity may help suppress poa annua for several weeks as the soil temps fall below 70 degrees.
Hope this helps! Feel free to email me at lawnphix@gmail.com
Hi, This is Jim. I enjoyed your research and wish I read it sooner! ! My lawn was diagnosed with widespread POA TRIVIALIS. I’ve been thatching and raking for days to remove this shallow-rooted brown eyesore over a very large area (although many sections are green also). I applied ROUND UP to assist is the process. The raking & removal are never-ending and at some point I will just deal with what’s left, cross my fingers, plug-aerate, seed, & fertilize. I wanted to ask if an application of TENACITY is warranted somewhere in this process – does this product actually attack the unwanted POA while leaving desired grass alone? I’m in the Northeast alone and it’s the first week of September. Getting late. Thanks, JIM
Hi Jim – thanks for the comment. Unfortunately Poa Triv is not labeled on Tenacity – neither as a pre-emergent or post-emergent.
You can, however, spray it before or on the day of seeding. It can help kill some weeds and also help prevent and suppress further weeds.
Hope this helps.
Hi: i live on eastern Long Island NY. Today 9/29/20 my lawn was aerated and overseeded. I was told my lawn has patches of bent grass and it also patches of clover.
I am aware that it is late in the season to overseed but it was done for a reason I won’t go into here.
Is it too late to use tenacity this coming week. If no do I apply with NIS? If yes when is the next best time to apply?
Thanks
Hi George. Generally Tenacity (Mesotrione) is used at seeding as a pre-emergent (no NIS). I personally haven’t tried killing Bentgrass at the same day/time as overseeding. You’ll end up with dead patches and no seed to grow and fill it in. Bank on at least 10 days for the Bentgrass to die off from Meso.
You might want to consider Round Up, depending on your situation. You could be seeding those areas within a week. Digging it out will only work temporarily; roots and fibers are bound to be left behind.
You want to avoid spring seeding if you can, but it is an option.
Not sure if this helps but gives you a few different ideas anyways.
Hello,
I hope all is well with you.
I live in Northern Utah and I have some scotch thistle rosettes. Will Tenacity work and is it too late to do it now? I just bought this home so I had no way to do it earlier in the year.
Best regards,
Ken B
Hi Ken – thanks for the comment. I see that thistle is listed on the Tenacity Herbicide Label for post emergent (with NIS). 2,4D should also work. Good luck!
Hello,
We have a sand lake lot with those darn sandburs. Will Tenacity work on those types of weeds.
Thanks
Mark,
Thank you for sharing your knowledge on Tenacity. I’m about to take the leap of faith with Tenacity in hopes of removing bentgrass and preventing it from returning.
I live in southeast Michigan and have bentgrass throughout my lawn and in large clumps/areas.
I just over seeded my lawn about a week ago and was wondering if I should wait until early spring to apply Tenacity or wait until next Fall?
After the bentgrass dies is it necessary to rake all the dead grass out?
I also would like your opinion on spot treating vs applying Tenacity to the entire lawn.
Thanks,
Jason
Hi Jason – I’d recommend applying towards the end of August. You’ll want 2 applications to kill the bentgrass before seeding. I’m not a fan of spring seeding.
After it turns brown and dies. you can scalp those areas, and bag, with your mower. This will ensure better seed-to-soil contact for your new/good grass seeds.
You can certainly spot-spray versus blanket spraying your entire lawn. Just make sure you spray outside of the bentgrass circles as the roots and runners expand beyond what you see on the surface.
Hello,
I live in Utah and we are rapidly approaching winter(although we are still reaching mid 40’s to 50’s during the day). I’ve acquired a lawn that seems to be dominated by crab grass and other fast/tall growing weeds. At this point, my grass seems to be growing extremely slow, but these weeds seem to be thriving. I was under the impression that most of these weeds would begin to die with the overnight freezing temps(25-35). Would it make sense to spray some speedzone and tenacity since it feels like I’m primarily just mowing weeds at this point.
Hi Brian. Crabgrass should be dead by now. However it did drop lots of seeds which will germinate next spring. Be sure to apply a pre-emergent like Prodiamine before the soil temps hit 55 degrees. Aim for late March/early April.
The only weeds now are your winter perennials and biennials like ground ivy. It may be too cold now but also check your soil temps. SpeedZone + Tenacity is a great combo. Be sure to hit these a little earlier next year (October).
I just have to wonder how much one has to spend for all of this maintenance. I just bought a new home a year ago with a full acre of grass, and just fertilizer/weed killer without all the added things to apply will run me $1,000. I want a golf course lawn, but I don’t want to have to sell a kidney to get it. Any recommendations?
A full acre is quite a bit of land. You should check to see if you have a SiteOne near you and set-up an account for discounted prices. If you buy commercial products versus big box stores, you might pay more up front but you will get many more applications.
Thanks, Mark. I’m getting ready to buy a NorthStar Tow-Behind Trailer Boom Broadcast and Spot Sprayer – 21-Gallon Capacity, 2.2 GPM, 12 Volt DC from Amazon. That’ll certainly make application easier. Fortunately, the Tenacity, dye, and surfactant aren’t that expensive even for one acre. Do you happen to know how often I should spray my yard with it? Does it require “maintenance doses” throughout the year?
Thank you so much for your reply!! Have a great weekend!
Hi Mike. Thanks for the comment. It depends on that you’re using Tenacity for. You’ll only need to blanket spray if you’re killing off a mix of weeds, killing bentgrass, or used as a pre-emergent when seeding. Depending on which weeds you’re targeting will determine the herbicide used, and number of applications and intervals.
I have well established St Augustine that is being taken over by bent grass. If I kill the bent grass, There are no seeds for St Augustine. What is the best seed to mix in with the Augustine.