Herbicides for fruit trees and corn fields

Does anyone use herbicides to keep grass away from there fruit trees? Can it be done without damaging the trees? I am killing my self trying to keep the grass and weeds away from the trees at my fathers farm using a Weed Eater… Plus I have one tree at my house that Zoysia grass around it that I am having a hard time getting rid of the grass…

I saw where this video where they recommended Poast herbicide.


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Poast and related grass killers only kill grass. So they are safe around fruit trees. However once you kill the grass broad leaf weeds move in if they aren’t already there.

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Glufosinate works well around fruit trees and is a lot safer than Roundup. Gets grass and broadleaf weeds. About 5X more expensive than Roundup.

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Hi Blueberrythrill,

I found a source for Liberty Sl (Glufosinate) that is not to expensive. Do you know the mix rate per gallon? There label is hard to read.



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I use about 6 oz in a 4 Gal backback sprayer, the same rate as roundup.

I keep it off my trees but if you hit a few root suckers on the apples it will not kill the trees

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That is a pretty light rate for original roundup and generics. Label called for 2% solution for most weeds back when a quart was recommended broadcast rate… In dry climates, liberty and generics won’t kill anything over 2 inches tall but the recommended rate is 42 ounce broadcast (at least it is here). I would think a 2.5 to 3 % solution and total weed coverage would be the equivalent.

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Yep, I believe my rate is a little light compared to the label but it gets the job done most of the time. Posion Oak, Trumpet Creeper and Bermuda Grass are exceptions. Some of my weeds have resistance to Roundup and the Glufosinate gets them.

You are very well informed on the rates! Do you spray Glufosinate over some type of Liberty GMO field crop in Texas?

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We have liberty link cotton since our major weed pest is now immune to glyphosate.

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Do you alternate Liberty Link with Roundup Ready each year or are the Roundup resistant weeds too bad?

I have quite a few weeds that are now resistant to Roundup in the orchard or Blueberries. I’m glad its just a problem on a small scale.

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Roundup is pretty much a grass killer here now. As the chemical red said, It wouldn’t kill a broadleaf weed if you set the jug on top of it.

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It is both Monsanto’s and lazy farmers’ fault. Monsanto for ads that said roundup was all you needed for effective weed control . Farmers because they believed it and neglected their preemerge incorporated, preemerge broadcast, and post emerge weed treatments of other modes of action.

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I’ve used generic roundup and had great results on broadleaf so far. guess i should mix it up so they don’t become tolerant to it. never been a fan of preemergents.

I had no idea that Roundup had lost so much effectiveness on broadleaf weeds in your area. I believe this is very significant information that will impact all of us!

I have just a few broadleaf weeds that Roundup will not touch. After June, I only spray glufosinate in the orchard in order to protect the trees, so it gets most of the weeds that Roundup missed.

Does it cost a lot more to grow Liberty rather than Roundup Ready Cotton in your area?

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Believe it or not, they also have dicamba and 24d resistant cottons now. Both of these will go the way of roundup soon I expect. There are generics for glufosinate so it is not so much the chemical cost as the necessity of spraying every ten days to burn down the weeds that don’t die. At first only mares tail was found to be resistant to roundup. Then new weeds began showing resistance yearly. When amaranth species started showing it in Mississippi and Arkansas, the battle was lost.
In some ways it is good that costs are not too low. When roundup resistant cotton came out,roundup was 60 -80 dollars per gallon. When it got down to 8, it was depended on too much.

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I know nothing about growing cotton, but I regularly use glyphosate under my peach trees.

Just as an FYI for folks who want to use glyphosate under their trees, I never approach anything near a 2% solution for peaches. I use about 1/2% solution in my tank which corresponds to the 2 quart per acre rate. At the speed I drive, it gets the weeds fairly wet. I’m referring to the 4 lb. concentrate, not the 6 lb.

I’ll admit at that rate, it doesn’t kill every single weed, but does a pretty good job here. It won’t kill sedge very good, nor mare’s tail. Otherwise it will kill most broadleaf and any grass. It will also kill peach trees if you get any drift on a newly planted first season tree.

For newly planted, and non bearing trees, I use gramoxone, which is basically a burndown like Liberty, but RU (and much more dangerous for the applicator).

I’ve used a “hot” 2% glyphosate solution in a pump up sprayer before, which will kill nut sedge here.

I’ve been using Sinbar as pre-emergent. It does a very good job controlling weeds under trees for the first part of the season. Weeds will start to emerge later, but they aren’t near as thick and happy, compared to ground which didn’t get Sinbar. Sinbar has no effect on mare’s tail.

On my sweet corn, I burned it down w/ glyphosate first and added simazine as a pre-emergent.

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Roundup ready beans and corn was all the rage. Now there is major issues where I live. We have 3 or more common weeds that are now almost immune to glyphosate. Many of the soybean fields are lousy with weeds this year. Many farmers have resorted to field crews to knock the weeds down mechanically by hand this year.

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if you are putting paraquat through a pump up sprayer you need to be very careful. Gloves,mask, the whole bit.

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So just to summarize and confirm what I learned in this thread -

  1. If I use Glufosinate (Liberty Herbicide) I should use 1.5 ounce per gallon (6 ounces in a 4 gallon sprayer per BlueberryThrill)

  2. BlueBerryThrill uses the same rate that is is used for Liberty herbicide with glyphosate (Roundup).

  3. Txpanhandle1 - In dry climates, liberty and generics won’t kill anything over 2 inches tall

  4. Olpea “Just as an FYI for folks who want to use glyphosate under their trees, I never approach anything near a 2% solution for peaches. I use about 1/2% solution in my tank which corresponds to the 2 quart per acre rate. At the speed I drive, it gets the weeds fairly wet. I’m referring to the 4 lb. concentrate, not the 6 lb” .I need to translate that to a per gallon rate. Not sure if that matches Blueberrythrill rate per gallon.

Thanks everyone for the feedback/information.

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One other thing I would mention, is that when using glyphosate, you need to use ammonium sulfate in the tank before you add the glyphosate. Most water contains enough cations to inactivate at least part of the glyphosate. By adding the ammonium sulfate (AMS) before the glyphosate is added, it ties up the cations so the glyphosate is not tied up. Also AMS is a fertilizer and causes the weeds to absorb more of the glyphosate than they otherwise would.

Another helpful thing to add is a little bit of citric acid to the tank. Glyphosate is unstable in alkaline water (i.e. most tap water), so adding a little citric acid will prevent the glyphosate from breaking down in the tank. Other herbicides can also benefit from an acidifier as well (i.e. Gramoxone and 2,4-D).

We rarely use Gramoxone through a pump sprayer. Mostly I spray it with a small boom sprayer, or use a power sprayer with a wand, for directed sprays. But I agree, it’s some nasty stuff to spray and one should be careful using it. (i.e. PPE). Thanks.


Just a few more points. Not all versions of Glufosinate are labeled for tree fruit. The PHI is 14 days for tree fruit.

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