Weed Killers - What's The Strongest/Most Effective?

[DoggyDaddy]

I'm assuming you want to someday plant/grow something on that spot of dirt.
If that's not a concern, the Punic Wars found salt to be effective.
I've put water softener pellets on fence lines. But don't tell on me.

When I was a kid, we had a small (4'x 6' maybe) "patio" outside the back door that was made up of concrete pavers. It was my job to keep the weeds pulled between the pavers. I'd have to do it 3 or 4 times a season. When I heard about "salting the earth", I pulled up all the pavers and spread rock salt under them, then replaced them. Voila! No more weeding (at least for a year or so)!

 

[Cameramonkey]

When I was a kid, we had a small (4'x 6' maybe) "patio" outside the back door that was made up of concrete pavers. It was my job to keep the weeds pulled between the pavers. I'd have to do it 3 or 4 times a season. When I heard about "salting the earth", I pulled up all the pavers and spread rock salt under them, then replaced them. Voila! No more weeding (at least for a year or so)!

Yep. Dad would spread rocksalt on the gravel driveway every spring when weeds would start. I think he only had to do it every couple years or so.

 

[Leadeye]

Boosting the percentage of active material usually works well as was discussed upstream. I have straight Roundup in a squirt bottle for stubborn weeds that are close to plants I want to save. Thistle should respond to concentrated 2,4D, spray in the evening after the plant stomates open.

 

[Judamonster]

I used pb blaster to clean a car part in my parents yard. Was a few years before anything grew there again. It still isn't 100% and it has been 15-20 years.

 

[greg]

41 % glyphosate 3oz, plus 1 tablespoon triclopyr plus 1 to 2 teaspoons spreader sticker all mixed up in a 1gal tank sprayer. this mix will kill just about anything including your lawn LOL you can get the chemicals on line at domyown pestcontrol.

Steve

This^^^^^

 

[firecadet613]

41 % glyphosate 3oz, plus 1 tablespoon triclopyr plus 1 to 2 teaspoons spreader sticker all mixed up in a 1gal tank sprayer. this mix will kill just about anything including your lawn LOL you can get the chemicals on line at domyown pestcontrol.

Steve

You can buy glyphosate at Rural King by the gallon.

 

[tsm]

We use Triplet SF on thistles and it kills them. Doesn’t destroy an entire area like Roundup. Sometimes the bigger ones take a couple of applications, but little ones usually succumb the first time.

 

[KokomoDave]

I'd buy the strongest vinegar available and put a bit of dish detergent in areas the areas of pets. Tordol blue plant killer (Rural King) works well but you gotta lop off the top and dribble it into the plant.

 

[OutdoorDad]

Speed Zone is

2,4-dichlorophenoxyacetic acid equivalent, 18.95%.

 

[Mij]

I’ve done away with extremely hard to kill Canadian Thistle in alfalfa stands by mowing extremely short every 3 or 4 days. Takes a whole summer to do it but it does the trick.

And as stated, mixed Round Up and Crossbow and diesel. In a used windex hand sprayer for spot spraying. Or 2-4D. JMO

 

[Cameramonkey]

I'd buy the strongest vinegar available and put a bit of dish detergent in areas the areas of pets. Tordol blue plant killer (Rural King) works well but you gotta lop off the top and dribble it into the plant.

That stuff isnt as effective on non-woody plants.

But saplings, and nuisance brush, absolutely! I swear by it.

 

[flyingsquirrel]

I saw 30% vinegar at Wally's with the weed killer. FYI

 

[wingrider1800]

FWIW, when I see a thistle I use my pocket knife and cut the stem just below the surface. It seems to work for me.

 

[Cameramonkey]

I saw 30% vinegar at Wally's with the weed killer. FYI

That stuff is one of my favorite chemicals.

For routine cleaning, if you mix it right, its actually cheaper than regular white vinegar by the gallon. 1 oz of that stuff in 6 oz of water is roughly the same acidity of regular vinegar. That gives you around 20 gallons of regular vinegar as I recall.

 

[bobjones223]

Thistle is one tough plant. We had a stone drive and had it paved two years ago. The thistle pushed up through 3" of asphalt and started trying to keep the drive as their home. Tordon RTU worked on mine.

 

[DoggyDaddy]

Thistle is one tough plant. We had a stone drive and had it paved two years ago. The thistle pushed up through 3" of asphalt and started trying to keep the drive as their home. Tordon RTU worked on mine.

That's what I use for volunteer trees when I cut them down, but I'm hesitant to use it in the flowerbeds.

 

[Hardscrable]

Are they newly germinated this spring ? If So I would spot spray with a minimum 2% glysophate mixture ( using 41% glysophate) spiked with 2,4-D and a spreader/sticker product ( or Dawn ) while actively growing, not during drought. Do not cut, mow, till, etc. for a minimum of 3 days.

If an established plant it needs to be treated in late fall. Thistles are a perennial and need treated in the fall when the herbicide will be transferred to the root. Otherwise you are merely burning off the foliage and not killing it.

 

[DoggyDaddy]

Are they newly germinated this spring ? If So I would spot spray with a minimum 2% glysophate mixture ( using 41% glysophate) spiked with 2,4-D and a spreader/sticker product ( or Dawn ) while actively growing, not during drought. Do not cut, mow, till, etc. for a minimum of 3 days.

If an established plant it needs to be treated in late fall. Thistles are a perennial and need treated in the fall when the herbicide will be transferred to the root. Otherwise you are merely burning off the foliage and not killing it.

I think by now these are established. I didn't realize they were perennials. I'll have to make sure to hit them in the fall, but for now I guess I'll try some of the suggestions here and at least keep them in check.

 

[Pepi]

Old engine oil LOL

 

[xwing]

41 % glyphosate 3oz, plus 1 tablespoon triclopyr plus 1 to 2 teaspoons spreader sticker all mixed up in a 1gal tank sprayer. this mix will kill just about anything including your lawn LOL you can get the chemicals on line at domyown pestcontrol.

Steve

Good suggestion! I recently sprayed down a whole bunch of thorn bushes using glyphosate alone. I guess I'll know in a couple of weeks if that is sufficient, or if I need to add other chemicals (as you suggested) to improve absorption.