Hi -

Does anyone have a recommended herbacide to kill johnson grass that will not kill jigs or bluestem? Looking for something that does not require an Ag license to purchase.. Looking to clean up about 20 acres of pasture...

Thank you

Gunny456 said:

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We use a product called OutRider. We use it to kill J Grass in our Bermuda and fescue fields. Works great but expensive. In granular form.
Was recommended to me by B-1-83 on here.

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thank you

Outrider works, but you've got to add the proper surfactant in the necessary quantity or you'll be pissing your money away. Putting a 16 ounce bottle of Dawn in a 1000 gallon tank and spraying will give very poor results.

Ask my hay guy how he knows.

Also, Outrider has a 'generic' competitor called Cryder. It's slightly cheaper, but the same stuff.

Rather than spraying, I've been looking at rigging up a home-made weed wiper with glyphosate to use in select areas, probably mounted on the front of an ATV.

This place sells kits to 'build your own.'

Rope Wick Applicators

I used Drexel non ionic Surf-Ac Surfactant at 2 pints per 100 gal with the Outrider.
First I tried the Cryder as it was cheaper. Had much better kill with the Outrider though.

No doubt that a cheap and very effective way to get rid of j-grass is to graze it when its young. Cows will eradicate it. But this time if year, when it's mature and woody stemmed, there's a significant risk of prussic acid (aka cyanide) poisoning so grazing it should be avoided especially in drought periods.

My curiosity is if you shred it and start the growth process over, will the Johnson restart and lose the toxicity?

My buddy who is a lurker with a master degree in range mgmt has said it is easiest to just graze it out when the conditions are right, meaning when it's not in a phase that is likely to be toxic. He said the cows will kill it in time.

Good advice I guess if you use the field for grazing by cows.

A bit of JG in a bale never really bothered me but starting to take over. Was planning on using Rezilon pre emergent . Now other options popping up so trying to get a bang with my buck.

WaldoWings said:

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My buddy who is a lurker with a master degree in range mgmt has said it is easiest to just graze it out when the conditions are right, meaning when it's not in a phase that is likely to be toxic. He said the cows will kill it in time.

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Dedicated Johnson grass hay fields (30+ acres) have existed on our family ranch, for decades. And the adjacent grazed pastures never see any (visible) Johnson grass growth.

ag94whoop said:

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My curiosity is if you shred it and start the growth process over, will the Johnson restart and lose the toxicity?

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If conditions are good, yes. Prussic acid off gasses as stem dries (after a hard freeze you can even smell it.) Once completely dry, cows can eat standing johnsongrass like hay.

If conditions are bad and the plant is stressed (like fresh regrowth after a fire that gets stressed due to summer heat and no moisture), that can be dangerous.

is johnsongrass the super tall stuff that quickly shot up around my new pond after the land was cleared and pond repaired? I can't even keep the stuff cut down it seems like it grows over 3-4 ft tall in 1-2 weeks.

I'd love for native bluestem from the field above the pond to take over... should I worry about runoff from any herbicides i use around the pond? I haven't reached out to any pond and fishery management companies yet or started to add any habitat or fish, but starting to look into it.

Ribeye-Rare said:

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It was INTENTIONALLY introduced into this country in the 1800's.

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As were many of our non-native invasives species by…… the US gov't

...and remedy + surfactant (or diesel) would not work on johnsongrass?

Micropterus said:

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No doubt that a cheap and very effective way to get rid of j-grass is to graze it when its young. Cows will eradicate it. But this time if year, when it's mature and woody stemmed, there's a significant risk of prussic acid (aka cyanide) poisoning so grazing it should be avoided especially in drought periods.

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No, not really. Prussic acid is a result of stress. Mature j grass doesn't have it unless it's been hit by frost (7-10 day wait to graze), or drought stressed followed by rain (may be quicker than frost for CN danger). I'm going with my agronomy and animal science profs on this one.

oh no said:

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...and remedy + surfactant (or diesel) would not work on johnsongrass?

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well the problem with that is you will have to spot spray which will be a real drag.

I see. Thanks.

I was hoping to attempt to shred it, even though it's gotten very tall and thick-stemmed, then drive around with the sprayer boom on. …but not sure if it would work and not sure if I risk harmful contamination in the pond I just had built.


Maybe I just spray some total vegetation control instead of remedy, spread some native grass seed a month later, and wait to stock the pond until next year?

oh no said:

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I see. Thanks.

I was hoping to attempt to shred it, even though it's gotten very tall and thick-stemmed, then drive around with the sprayer boom on. …but not sure if it would work and not sure if I risk harmful contamination in the pond I just had built.


Maybe I just spray some total vegetation control instead of remedy, spread some native grass seed a month later, and wait to stock the pond until next year?

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I doubt it would hurt your pond. Also if you are going to just kill all of the exidting vegetation and reseed, just make sure whatever you spray doesn't have a powerful preemergent or that you look into how long the preemergent will stay active. It could affect the germination of whatever you reseed with.

it appears that every herbicide that contains sulfosulfuron (which seems to be the best control to target johnson grass), such as Outrider, Certainty, and all the others I can find, requires an applicator's license.

...so if there's no risk to the pond from any runoff, I'm thinking i try to shred it now, again in early fall, then go glyphosate total veg control in september/october and spread some grass seed in march that I hope can take over so there's no 5' tall forest of johnson grass around my new pond next year.

Back in the day, we used to say "Baptists and Johnsongrass are taking over Texas"! Don't believe either is true today, but Johnsongrass can be prolific in the right conditions (usually where it's unwanted).

My experience was that cattle preferred it and kept it grazed back whenever it appeared randomly amongst other grasses. But prussic acid poisoning is a real thing that must be managed for. It requires an awareness, but generally not a big concern.

Seek app confirmed it is indeed a Johnson grass forest around my recently cleared and re-constructed pond.

B-1 83 said:

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Micropterus said:

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No doubt that a cheap and very effective way to get rid of j-grass is to graze it when its young. Cows will eradicate it. But this time if year, when it's mature and woody stemmed, there's a significant risk of prussic acid (aka cyanide) poisoning so grazing it should be avoided especially in drought periods.

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No, not really. Prussic acid is a result of stress. Mature j grass doesn't have it unless it's been hit by frost (7-10 day wait to graze), or drought stressed followed by rain (may be quicker than frost for CN danger). I'm going with my agronomy and animal science profs on this one.

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Thats fine. My agronomy degrees, work experience with TAEX, and 30 years of work experience in weed science say otherwise.

It's 1.33 oz
1.25 is cutting the rate
Once and a third

Other options are divergence, another generic

Also, use a better surfactant than Drexel cheap A$$ 80/20

Outrider, et al, is not a RUP