Weed wiper... Johnson grass. Anyone using one?

[Jrasband]

It is easy to avoid prussic acid poisoning with rotational grazing. Unfortunately, most cattle farms are not rotational grazers.

 

[Dadnatron]

It is easy to avoid prussic acid poisoning with rotational grazing. Unfortunately, most cattle farms are not rotational grazers.

How long, after stress ie drought and/or frost, would you wait before putting them back into a pasture that has JG in it?

This is the information I don't know. How long must I avoid that pasture to be safe. I've heard a week or so, but I don't know.

 

[Jrasband]

Prussic Acid Johnsongrass Duration
Prussic acid can be a concern with Johnson grass for a period of time after the plant is stressed, such as during drought or frost. The risk is highest in young plants and during periods of stress. For example, after a frost, prussic acid levels can be particularly high and may persist for a few days.
It is recommended to wait at least 14 days after a frost before allowing livestock to graze on pastures with Johnson grass to ensure that prussic acid levels have subsided.
Additionally, if Johnson grass is mowed and baled, the prussic acid will dissipate over time, and it is advised to wait at least 90 days for the hay to cure before feeding it to cows.
In some cases, prussic acid can decline within 2 to 3 days after the plant is dead, but it is still important to exercise caution and follow recommended guidelines to ensure the safety of livestock.

AI-generated answer. Please verify critical facts.

 

[Blue Mule]

Sorry to bring this topic back up, but this summer proved to be relentless for my lawn directly around my house. The fields are fine, but I don't want Johnson Grass around my house. It's unsightly and it chokes out fescue and other desirable lawn grasses. I have tried to manually dig out as much of it as I can, but it's quickly going out of control. I've got a few 10' x 10' patches of it now that are spreading. It would take a month of Sundays to manually dig that all out with a garden spade.

So back to the topic of herbicides.. are there any that I can actually purchase myself that are effective at controlling Johnson Grass but will not harm fescue? I know that's a tall order, but if one exists please list it and I'll buy some.

 

[Dadnatron]

For me, the issue with JG and Prussic acid (form of cyanide) is summer stress more than frost, although that is an issue as well.

I have about 30-40ac that is a mix of forage, but has become heavily infested with JG (>70-80%). I will rotationally graze, however it’s not as easy as simply ‘avoiding’ during stress. Especially summer drought, as different areas of the pasture have varying degrees of drought stress simply because of surface rock, soil depth, other forage, etc. Some areas will be more significantly stressed than others. At least fall stress happens across the pasture for the most part with the frost.

I’d love to leave it and use it as summer forage, and in 2024 I could have as we had pretty much had good rain all summer. This year we were almost 70days without appreciable rain. The issue with JG is it is tough, tall, and prolific. It shades out competition. I think people who see it as ‘added forage’ don’t have as heavy of an infestation as some other folk. My farm was hayed heavily for years, so they loved the biomass. But they didn’t graze it. If there was more forage mixed in or less density of the JG, I’d be fine. But losing even 1 $3000 heifer makes it a real concern for me.

I just bought a weed wiper to target it, so I’ll try to let you know how it goes next year. I doubt I’ll do anything this fall.

I just want more ‘other forage’ in there in order to mitigate the effects if any.

 

[RayIN]

What the great Joel Salatin said in the recent Stockman Grass Farmer newspaper when someone asked about how to rid there hayfield of Johnson Grass. " Cows love Johnsongrass : It's a wonderful summer forage. In mid-summer; it's the prefered species and unless the cows are moved from paddock to paddock they'll kill it out with overgrazing."

Joel Salatin is the editor of Stockman Grass Farmer and the owner of the wonderful farm Polyface in Swoope VA.

Yep! The largest group of farmers that don't like Johnson grass are row-croppers, cattlemen love it.

 

[Hay Dude]

IMO, JG fears are a little overblown. I’ve yet to see anything die from eating it. Key is to avoid grazing on it after frost or drought. Otherwise, let them graze on it. That is how you get rid of it.

 

[kenmac]

I don't have any JG but I do have plenty of crab grass I'd love to be gone. It has taken over and choked out my fescue hay field . People around here spray JG with outrider with min results

 

[MMC]

For me, the issue with JG and Prussic acid (form of cyanide) is summer stress more than frost, although that is an issue as well.

I have about 30-40ac that is a mix of forage, but has become heavily infested with JG (>70-80%). I will rotationally graze, however it’s not as easy as simply ‘avoiding’ during stress. Especially summer drought, as different areas of the pasture have varying degrees of drought stress simply because of surface rock, soil depth, other forage, etc. Some areas will be more significantly stressed than others. At least fall stress happens across the pasture for the most part with the frost.

I’d love to leave it and use it as summer forage, and in 2024 I could have as we had pretty much had good rain all summer. This year we were almost 70days without appreciable rain. The issue with JG is it is tough, tall, and prolific. It shades out competition. I think people who see it as ‘added forage’ don’t have as heavy of an infestation as some other folk. My farm was hayed heavily for years, so they loved the biomass. But they didn’t graze it. If there was more forage mixed in or less density of the JG, I’d be fine. But losing even 1 $3000 heifer makes it a real concern for me.

I just bought a weed wiper to target it, so I’ll try to let you know how it goes next year. I doubt I’ll do anything this fall.

I just want more ‘other forage’ in there in order to mitigate the effects if any.

My personal experience has been that a weed wiper will work, at least with a 50/50 Round-Up mix in the tank. I bought a used one with sponges and fixed it and did a test of a couple of pasture fields. It did actually work, at least in my experience.

The effort will be getting it done on time and adjusting the "drip" or wetting of the absorbing media. The good news is weeds and Johnson grow tall and quick so they are good targets up high and you leave the forage grass below alone (uh, mostly).

I might suggest testing a smaller field first to get your procedures and ground speed down. It will only take a few days to judge the results. And you might speak with your KY County Extension Agent about your plans for the coming year. They may know some local farmers who are using this system who can give you pointers. Hard to eradicate Johnson, but you can definitely set it back on its heels which seems to be what you want.

And while some folks are complacent about stressed Johnson, I don't want to take chances either. Losing a fine bred cow with no reason to explain it happens if you're in the business. Rarely, I admit. But I still spray all the poison hemlock I can find and clean up any downed wild cherry trees as soon as I can get to them.

And I do admit cattle consider Johnson grass as candy and really keep it grazed down, though. But, in my opinion, it has to be controlled and your herd managed properly to use it safely.

Put it this way... You've got $200K worth of cows and a fenced and gated field that has a large Johnson presence. It frosted last night. You really want to open that gate in the next day or two?

 

[Spike56]

Sorry to bring this topic back up, but this summer proved to be relentless for my lawn directly around my house. The fields are fine, but I don't want Johnson Grass around my house. It's unsightly and it chokes out fescue and other desirable lawn grasses. I have tried to manually dig out as much of it as I can, but it's quickly going out of control. I've got a few 10' x 10' patches of it now that are spreading. It would take a month of Sundays to manually dig that all out with a garden spade.

So back to the topic of herbicides.. are there any that I can actually purchase myself that are effective at controlling Johnson Grass but will not harm fescue? I know that's a tall order, but if one exists please list it and I'll buy some.

Try looking up Target 6 herbicide. Works great on Johnson Grass and Crab Grass. BUT, should only be used in areas without animals. Fescue safe, not certain