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I'm losing the weed battle, what next?

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14K views 27 replies 16 participants last post by  thebmrust  
#1 ·
My lawn is primarily Marathon 2 and since hiring a new gardener last year, I now have a lot of weeds. I joined this forum to get a handle on getting my lawn healthy again and read about using Tenacity. I have applied two applications of Tenacity (with Surfactant about 5 weeks apart) and I'm still seeing a lot of the weed(s) pictured. I have used a thatch rake to remove some of the dead weeds and its creating a lot of dirt patches in my lawn. I'm also not sure if some of these weeds are new (because they are 4-6" in diameter), and have grown since the last time I used Tenacity. My plan was for the Tenacity to eradicate all of the weeds and then over seed to fill in all of the dirt patches. Given that I'm seeing more of the same weeds after using Tenacity, what do you think I should do next to take care of these weeds and fill in the dirt patches?

Thank you!

***Also, here's my soil testing results and I'm guessing the weed is Black Medic? Mainly because my soil is nitrogen deficient and receives full sun.



 
#7 ·
Belgianbillie said:
Im confused by everyone using tenacity all of a sudden. This was considered a tier III herbicide a few years back.

What happened to mixing WBG and WBG Max together?
:yahoo: :yahoo: :yahoo: I've been saying this all Spring. There seems to be a huge infatuation with Tenacity in 2021. I think people may believe it's a stronger herbicide, so why not start there.

I always suggest beginning with a mix of Weed B Gon (2, 4-D, Dicamba & MCPP) + Weed B Gon CCO (Triclopyr) and doing two apps 14 days apart. This will more than likely clear all of the common broadleaf weeds. From there you can move on to something stronger if problem weeds persist.

The key is patience. It can take 7 to 10 days to start noticing the effects of your first app. Weeds are not going to die after 4 or 5 days and be gone for good.
 
#9 ·
fwiw i like tractor supply and the gordon's brand and being able to get that immediately should i decide to versus mail order. The gordon website is great for easy access to information:

https://www.gordonsusa.com/products/lawn-garden/weed-control/

their trimec concentrate I've had great results with, it was my first after joining this place and decided to get serious and stop buying granular crap at depot.

Regular trimec wed killer (2-4-d + mecoprop + dicamba) lists "black medic" and being controlled.

or if you want to plan for future problems...

get the trimec + crabgrass, which contains quinchlorac.

or there is trimec + nutsedge control which has sulfentrazone.

another heavy duty chemical for tough stuff is triclopyr, That is what the box store ortho weed killer + clover is, at 8% concentration which I recently used and it does work. Gordon's has "brush-no-more" which is trimec + triclopyr 7% but i'm not sure how hard it can be on lawn grass it does not specifically say... it compares to other professional herbicides that are lawn safe. But you don't need this specifically for black medic. I only mention it if you're like me and 1 quart will last you 10 years... i have overgrown woods so i lean towards any of the basic 2-4-d weed killers and specifically triclopyr, and that solves all my problems.

I've never used tenacity, but with what I mentioned above and how available that is I don't see why tenacity is so attractive... especially when mail order to my state is restricted. Definitely use some type of surfactant when liquid spraying water mixed weed killer concentrate.
 
#10 ·
you might also find useful...

http://www.fairfaxgardening.org/wp-content/webdocs/pdf/WeedKillers.pdf

for the mention of mixing CCO with the regular version of weed b gone, that is simply adding 8% triclopyr to trimec. So I don't doubt it definitely works. Whether that cocktail is specifically ever needed I suspect not likely for a good lawns with minor weeds here and there but that's just my opinion.

Here's the comparisons for anyone interested
  • Ortho Weed B Gon
  • 8% 2-4-d
  • 2% mecoprop
  • 0.3% dicamba
  • Ortho WBG + CCO
  • 8% tricloypr

  • gordon's brush-no-more
  • 16.5% 2-4-d
  • 1.38% dicamba
  • 7.81% triclopyr
  • Gordon's trimec
  • 7.6% 2-4-d
  • 1.8% mecoprop
  • 0.8% dicamba

gordon's brush-no-more has higher concentrations of 2-4-d and dicamba so it would probably be there that makes it not lawn friendly if you do not mix appropriately.
 
#11 ·
I threw down some Ortho WeedClear (2,4-D, dicamba, mecoprop) on my front yard yesterday. I almost mixed it with Ortho CCO but chickened out at the last second since it was my first time using a sprayer and I didn't want to screw up my grass.

Question(s): I have some clover issues; should I wait to see if the WeedClear takes care of it? Or should I just go ahead and put down the CCO? If so, do I need to wait to put down the CCO (e.g., X days after the WeedClear)?
 
#12 ·
r7k said:
for the mention of mixing CCO with the regular version of weed b gone, that is simply adding 8% triclopyr to trimec. So I don't doubt it definitely works. Whether that cocktail is specifically ever needed I suspect not likely for a good lawns with minor weeds here and there but that's just my opinion.
This is great point. The goal of any homeowner should be to prevent weeds organically through proper cultural practices - growing a thick and healthy turf stand along with properly timed pre-emergent. If both done correctly, you shouldn't need post emergent herbicide anymore, or least very rarely.

Once I got my old lawn to what I would call a "tier 3" level, I didn't need post emergent. I saw maybe 3 weeds in my lawn last year. The same lawn that used to be covered in dandelions.

Post emergents are great when you're starting out. They shouldn't be used as a crutch ad infinitum. We should all try to be somewhat responsible stewards of the planet.

@B Dig does the product label for WeedClear say it controls clover? If so, I would wait two weeks then mix your CCO and spray the mix together.
 
#13 ·
Harts said:
r7k said:
for the mention of mixing CCO with the regular version of weed b gone, that is simply adding 8% triclopyr to trimec. So I don't doubt it definitely works. Whether that cocktail is specifically ever needed I suspect not likely for a good lawns with minor weeds here and there but that's just my opinion.
@B Dig does the product label for WeedClear say it controls clover? If so, I would wait two weeks then mix your CCO and spray the mix together.
The label does list clover, so I'll wait a couple weeks then mix the two and spray. Actually, the label also lists chickweed and oxalis, which makes you wonder why they would even make CCO if the other product supposedly takes care of them. I get that CCO uses a different chemical. Probably some marketing shenanigans to make the list of affected weeds longer on the WeedClear/Weed B Gon.
 
#15 ·
superkaz661 said:
Lots of suggestions for wbg (because it has triclopyr). My go to is crossbow, which is 16% triclopyr and 34% 2, 4d. Mix it at 1.5% (2oz per gallon) and theres almost no yard weed that will stand a chance.
Wbg and its cco version combined have more active agents/MOA, which prevent herbecide resistance in case some survive. Concentrations in the bottle are irrelevant and only guide dilution ratio. AI applied remains the same per app after dilution.
 
#16 ·
The original poster's lawn is TINY, < 250 sq ft, and in Los Angeles, CA. It seems like you could kill the weeds with ready to use spray bottles from Home Depot or (Ortho Weed B Gone with Crab Grass Killer).

Assuming Marathon 2 is tall fescue, that is probably not the easiest grass to grow in LA since it's a cool season grass and doesn't do well in high temperatures. You should consider converting zoysia or bermuda, either one of those will perform way better and require less water in your climate.

Zoysia and Bermuda spread by rhizome, so if you have planting beds around that little patch of grass, you will need a plan to "contain" the grass or you'll be constantly fighting to keep the grass out of your planting beds. Bermuda will be harder to contain than zoysia. Zoysia also needs less water to be healthy vs Fescue and other types.

A well maintained patch of zoysia will also resist weed pressure better than most other grass.... In a small lawn like this a 1 gallon jug of liquid/balanced fertilizer and hose end sprayer would be a good plan to handle most of the fertilzer needs.

Let us know if you need help with the soil test report interpretation.
 
#17 ·
uts said:
superkaz661 said:
Lots of suggestions for wbg (because it has triclopyr). My go to is crossbow, which is 16% triclopyr and 34% 2, 4d. Mix it at 1.5% (2oz per gallon) and theres almost no yard weed that will stand a chance.
Wbg and its cco version combined have more active agents/MOA, which prevent herbecide resistance in case some survive. Concentrations in the bottle are irrelevant and only guide dilution ratio. AI applied remains the same per app after dilution.
Thanks for your thoughts, but the development of herbicide resistance in the home lawn is a non-issue, unless you are really trying, and repeatedly, to do it wrong. I offered my take of an effective herbicide combination at a known rate, that provides the user with both simplicity and value. If you dont like it, thats fine. But dont not like it for reasons that arent valid.
 
#18 ·
superkaz661 said:
Thanks for your thoughts, but the development of herbicide resistance in the home lawn is a non-issue, unless you are really trying, and repeatedly, to do it wrong. I offered my take of an effective herbicide combination at a known rate, that provides the user with both simplicity and value. If you dont like it, thats fine. But dont not like it for reasons that arent valid.
I didn't mean to offend but that said I wish that home lawn weed resistance was not an issue. The homeowner community here is only a miniscule fraction, a lot is managed by companies which carry the same risks as a homeowner applied lawn (be the nuts here or not). The weeds in your lawn are not limited to you, they migrate to and from far away places.

Poa annua and goose grass use to be simple stuff but now are resistant to simazine and glyphosate. ABG is getting resistant to prodiamine. The concerning thing is the invasiveness of a cool season ABG in warm turf and goose grass (warm season weed) in cool season grass due to its resistance. There are increasing resistance in nutsedge, plantains, spurge and crabgrass. Not saying that a home lawn was responsible for those but they affect us and there is increasing use of herbecides in home lawns both by owners and companies. Yes, the literature is from golf courses because that's where most studies can be done and people actually send out plant analysis. It's like antibiotic resistance outside the hospital. It's there, only the people who get to the hospital are studied, rest dont because they move onto somewhere else -dont think of the US only.(getting OTC antibiotics was and continues to be the cause). I know I digress but as a student of genetics this hits close to home.

Also what is not recognized by homeowners is herbecide rotation and follow-up with a different herbecide if something survives (let alone optimum timing, adjuvants). There is reason why there is an increasing alarm for the number of people using tenacity in home lawns as a standalone post emergent.

I'm guilty of these things before some reading and realizing the potential. It's an additive effect of everyone and something that will be seen a few years down the line.
 
#19 ·
B Dig said:
I threw down some Ortho WeedClear (2,4-D, dicamba, mecoprop) on my front yard yesterday. I almost mixed it with Ortho CCO but chickened out at the last second since it was my first time using a sprayer and I didn't want to screw up my grass.

Question(s): I have some clover issues; should I wait to see if the WeedClear takes care of it? Or should I just go ahead and put down the CCO? If so, do I need to wait to put down the CCO (e.g., X days after the WeedClear)?
I would wait to see if the regular "ortho weed b gon" which is 2-4-d and/or trimec takes care of your clover.
Wait like two weeks, by then you should see visible change in the clover.
If not, then buy the weed b gone + oxalis/clover/chickweed which has triclopyr on the label; it's only like $10 for the quart and is one of the few things i find acceptable to buy at depot.
Then simply spray the remaining clover with only weed-b-gone+CCO (8% triclopyr); I believe the label says 1 ounce to every 200 feet so 5 ounces to 1 gal of water- spayed over 1000 sqft if you are blanket spraying but don't blanket spray if you do not need to just hit the clover.

And use a surfactant, I don't think depot/lowes sells it, i know tractor supply sells it (i bought a gallon for like $40 which will last me a lifetime) otherwise mail order a smaller bottle of it; to a 1 gallon sprayer you add like 1/4 ounce.

rationale: you already sprayed 2-4-d and/or trimec chemical, if that didn't affect the clover then there's no good reason to use it again + triclopyr mixed in. you'll just be stressing the grass at that point and running yourself closer to the published maximum put down rate of the 2-4-d / trimec chemicals for the year so don't do that if there's no good reason to. If u mix trimec at the proper rate and spray it it'll work very well. it's when people get worried i don't wanna mix too much in fear of burning grass then the stuff isn't effective. So it really helps to know your chemicals, their concentrations in the various brands, and compare the mix rates from the pro products to the store bought products... you'll notice your mixing 5 oz of depot ortho weed-b-done to 1 gal per 1k sqft versus a pro type product mail ordered your often mixing at 1-2 oz per 1 gal. Doing the regular weed-b-gon by itself in my opinion was probably better so u can wait and see the affect; i would only mix trimec + triclopyr if i knew there was a high weed density plus clover and other woody weeds that triclopyr is needed for.

and don't spray at 11am and then have high noon+afternoon sun evaporate and cook off the sprayed chemical. so plan on being able to spray sometime that is at least a full day after mowing, spray in the evening when sun is no longer hard, and there will be no rain for the next ~ 2 days; use a surfactant and whatever you spray can sit easily for a good time and get into the weed leaf, and it'll work.
 
#20 ·
Thanks for all the replies and helpful information! I sprayed the remaining WBG CCO I had on hand (with a surfactant)and will buy both WBG flavors and use that in 2 weeks. In a week I'm going to fertilize, add N and potassium sulfate (which my soil lacks per the report). When appropriate I'm then going to thatch, over seed/top dress and hopefully that will greatly improve my lawn. I'll respond to this string in a few weeks with an update.
 
#21 ·
johnklein25 said:
The original poster's lawn is TINY, < 250 sq ft, and in Los Angeles, CA. It seems like you could kill the weeds with ready to use spray bottles from Home Depot or (Ortho Weed B Gone with Crab Grass Killer).

Assuming Marathon 2 is tall fescue, that is probably not the easiest grass to grow in LA since it's a cool season grass and doesn't do well in high temperatures. You should consider converting zoysia or bermuda, either one of those will perform way better and require less water in your climate.

Zoysia and Bermuda spread by rhizome, so if you have planting beds around that little patch of grass, you will need a plan to "contain" the grass or you'll be constantly fighting to keep the grass out of your planting beds. Bermuda will be harder to contain than zoysia. Zoysia also needs less water to be healthy vs Fescue and other types.

A well maintained patch of zoysia will also resist weed pressure better than most other grass.... In a small lawn like this a 1 gallon jug of liquid/balanced fertilizer and hose end sprayer would be a good plan to handle most of the fertilzer needs.

Let us know if you need help with the soil test report interpretation.
I agree with what you're saying but where I live, the average temp is 66 degrees and it rarely gets above 82. Also thanks for your offer on interpreting the soil test report. I was lucky enough to speak with the person who conducted the test on the phone and he explained the results. 👊
 
#22 ·
California is such an interesting state from a climate standpoint... we midwesterners often forget that. San Diego and San Francisco are famous for having "micro climates" I guess the LA region is the same....
 
#23 ·
Belgianbillie said:
Im confused by everyone using tenacity all of a sudden. This was considered a tier III herbicide a few years back.

What happened to mixing WBG and WBG Max together?
I use Tenacity to kill invasive grasses that aren't killed by regular weed products since technically they aren't weeds. Also to use as grass seed safe pre-emergent during seeding.

Anything else I mostly use Speedzone.
 
#25 ·
Harts said:
This is great point. The goal of any homeowner should be to prevent weeds organically through proper cultural practices - growing a thick and healthy turf stand along with properly timed pre-emergent. If both done correctly, you shouldn't need post emergent herbicide anymore, or least very rarely.
I cut at 3.75", twice a week. Mostly mulch. I sharpen my blades a few times per year. My yard is thickening up nicely but still have a good amount of weeds after spraying a pre-em. I'm pushing Level 2 compared to the neighbor's low cut clover. My question is - when is the properly timed pre-em? What pre-em do you use and do you make your own concoction?

Currently only seeing one kind of weed in my yard. Which is progress compared to last year. Only applied some fert and tenacity in April.
 
#26 ·
grasscorrection said:
Harts said:
This is great point. The goal of any homeowner should be to prevent weeds organically through proper cultural practices - growing a thick and healthy turf stand along with properly timed pre-emergent. If both done correctly, you shouldn't need post emergent herbicide anymore, or least very rarely.
I cut at 3.75", twice a week. Mostly mulch. I sharpen my blades a few times per year. My yard is thickening up nicely but still have a good amount of weeds after spraying a pre-em. I'm pushing Level 2 compared to the neighbor's low cut clover. My question is - when is the properly timed pre-em? What pre-em do you use and do you make your own concoction?

Currently only seeing one kind of weed in my yard. Which is progress compared to last year. Only applied some fert and tenacity in April.
I currently use Prodiamine but have used Dimension in the past.

For Spring apps, you want to get either product down as soil temps are reaching 55F. You can do another app 6-8 weeks later if you'd like - as long as you aren't planning to seed in the Fall.

Your Fall application needs to go down before soil temps dip below 70F.