Syngenta Tenacity Herbicide - Pre-Emergent and Post-Emergent Weed Control, 8-oz. Liquid Weed Killer for Lawns and Turf Grasses, Active Ingredient Mesotrione Herbicide

Product is working great! After 1 week of spraying I started seeing the weeds trying white. It definitely showed me that there were a lot more weed grasses in my yard than i expected. It also is killing off what I thought was clumping fescue. Very pleased on the results and well worth the price.

I have been trying for some years to identify and control the undesirable lawn grass called nimblewill. I thought it was Bermuda grass, which is similar, but it is somewhat different.The nimblewill has been slowly and consistently spreading and taking over my lawn for a number of years. It probably had taken about 20% of the lawn (about 0.7 acre lot). I thought it was pretty much hopeless. None of the lawn weed killers or crabgrass killers that don't harm the desirable grass will phase it. I thought I would have to roundup huge areas or most of the yard to get rid of it.The Tenacity is expensive, $60 or so for 8 oz. But for the number of gallons it makes (you use a syringe to measure it out, and it only takes about 1/2 teaspoon per gallon), it's really not that much more expensive than any other lawn herbicides or general vegetation killers for that matter. I have mixed and sprayed 22 gallons of the Tenacity, 2 gallons at a time, and I have only used about 1/3 of the bottle. I also used a surfactant, which is relatively any expensive and is supposed to increase the effectiveness. The Tenacity is a tanish, milky liquid. You don't want to get it on you. I was careful not to, but if I got just a minute drop of overspray on the skin, I could feel it burn.Anyway, I walked around and sprayed the all the visible nimblewill in various sections of the lawn 2 or 3 times during late June and early July, when it was actively growing in the hot weather. It was a little slow and time consuming, but it was effective, and I didn't waste the tenacity or over apply it. I tried to do it when it wasn't too hot or dry or right before rain, although I don't know if that matters . Anyway I walked around and hit the nimblewill in the all the different areas of the lawn at least once, maybe hit some bad places a second time. I sprayed some big patches, and many more isolated clumps where it was just starting to spread among the other grass. It is relatively easy to spot even when it is green and growing. It is blueish, low growing, and the grass leaves are flat and up to about 1/8" wide. I had no trouble spotting it among the desirable grasses when I was walking around spraying.At least 3-4 days after spraying, the leaves of the nimbewill grass start to turn white on the ends, then the whole upper grass leaf will turn white. Kind of unusual. It stays that way for a while. It stops growing and eventually it turns brown and dries up, but it takes several weeks for the whole kill process to complete, even in hot, relatively dry weather. But you can see results pretty soon, and continued results over time, and it's gratifying.It's hard to say if the other desirable grasses were harmed significantly or not, because it has been very hot and relatively dry. There is no obvious evidence of it, but some of the nimblewill patches were thick, meaning big brown spots, and some of the rest of the grass is turning brown anyway now due to heat and lack of moisture this summer, which is a little worse than normal. I plan to slit seed the whole yard closer to fall, so I don't really care if I lose a bit of desirable grasses to collateral damage or not. I am gratified just to see very little living and actively growing nimblewill at this point.Anyway, at this time or the summer, when it is usually thriving and will soon go to seed, I have very little green nimblewill in my lawn. I plan to make another pass or two soon and hit any more that I see that is still green.Bottom line with about 1/2 of a 8 oz. bottle this summer I realistically expect I will kill at least 85-90% of huge nimblewill infestation in a 0.7 acre lot. I will have plenty of Tenacity left to spot treat any I see for the next couple of years, and I expect to see a lot less each year. I have hopes of essentially eradicating it. They don't claim this is possible and say you can only "control" it, but I think with some diligence you can eradicate it for practical purposes.I also learned that the Crabgrass and weed preventers that are applied in the early spring help control nimblewill and keep it from spreading from seed. I had stop using these crabgrass preventers several years back because I had the crabgrass under control in my lawn. Not a good idea, because I think that helped allow the nimbelwill to spread uncontrolled and infest the lawn. Nimblewill goes to seed in the hottest, driest part of the late summer when you aren't mowing often. So you inadvertently allow the seeds to form and spread before they are mowed down. But I started using the crabgrass preventer again this spring, mainly to help control the spread of the nimblewill via seed, and I plan to continue using it as part of my efforts.

Great product. Wish I came across this many years ago to solve my lawn maintenance woes. Scott's Tall Fescue seeding introduces so many varieties of weeds, is unbelievable. I have always struggled to address until now. I can now have a totally weedfree lawn going forward when I seed again in the Fall. This is just my preliminary review after one week of application. I am giving 4-stars now because it's so promising. I recommend Tenacity.

Great product, it works like it is supposed to but I find it very expensive and somewhat difficult to properly use.

As expected

I bought two selective herbicides, tenacity & quinclorac. Our yard was recently expanded, and our existing lawn was impacted from the machinery, irrigation reno, and general foot traffic / stress. Given all that, crab grass sprouted through the existing lawn. Any pre-emergent barrier that was there was broken so here comes tenacity & quinclorac. I used quinclorac w/ MSO first on the larger crab grass patches and it worked well, but even with a dye in the mix I had missed spots. I read that tenacity bleaches the crab grass and thought that was a novel idea to not only kill the crab grass but help me to identify which patches i may have missed. I sprayed the tenacity with AO's surfactant, using dye as well to visually help, and let it get to work. Now I'll admit i was a bit more free in my spraying of the crab grass, often times fanning over larger areas of crab grass / healthy fescue/KBG. The first few days go by and the crab grass indeed did bleach out and began dying. However, about 7-10 days after that my healthy fescue/KBG began to bleach as well. I measured very accurately per the instructions, so I don't believe the mix was too hot. Another 7-10 days later, the fescue/KBG that was hit has died completely. I water my lawn regularly, and fertilize regularly (typically with milorganite). I wonder that perhaps the summer heat / sun was too much for the fescue/KBG grass, given the stress it was probably under from the tenacity spray. The end result, now about 3 weeks later, is that i have large patches of dead grass scattered throughout my lawn. I'm chalking it up to the summer heat/sun being the X factor, but man am i disappointed.TLDR; I'd be very cautious about when you spray this herbicide. I don't think the surrounding grass can withstand the stress this herbicide puts on it when coupled with hot summer heat / sun, i think it's just too much to handle. I didn't have issues with quinclorac and this situation, so i'm going to stick with that moving forward. As another reviewer said i'll stick to tenacity in our mulch beds, and quinclorac for the lawn. Lesson learned.

works as advertised