Weed killer for farmers

Please recommend weed killer for farm. I just moved my backyard nursery to a farm. I propagate fruit trees, jujube, persimmon, peach, plum and flower trees etc. It’s impossible to pull weeds by hand. So please recommend a weed killer, that doesn’t hurt trees.

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Hi Sophia,

That’s a pretty general question. You might get better answers if you can be more specific. What kind of weeds are you trying to kill (i.e. grasses, or broadleaf)? Are you looking for a pre-emergent, or a contact spray? Are you looking to burn the tops down, or a systemic?


Remove light from the equation.

Trees etc do this naturally by shedding leaves or needles to smother the competition.

Humans do this artificially with cardboard/mulch, fabrics and plastics.

Man has invented tools to do this.

Here is a human killing a dandelion


If you want good answers on poisons and chemicals there are lots of those suggestions on Facebook on the Backyard Fruit Growers page. Likely similar suggestions coming soon on here.

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Kill all weeds, except the trees. I just planted some rootstocks, and plan to sow some seeds soon.
I have a part that I sowed last year and they are small seedlings now.
I have no idea what kind of weed killer I need.
I use hands, mulch, etc to prevent weeds in my backyard. I just circled several acres on the farm for my nursery. So help needed.

I am not sure what you are doing and why you want to kill everything but trees. Glyphosate will kill many perennial and annual weeds and most grasses. It will harm or kill many woody plants as well

I will add this as well…every “farmer” I know attends at least annual meetings/symposiums on herbicide use. All are also licensed to apply limited use herbicides/pesticides.

Do not just jump wildly into spraying chemicals willy nilly


I don’t use any herbicides, so I can only suggest what I have seen based on reading, etc. But Tom Wahl of Red Fern Farm recommends taking out everything if you are establishing a new chestnut orchard with several passes of Glyphosate, then planting orchard grass in the isles between the rows for easy mowing and maintenance and using Oust on an annual basis to keep weeds suppressed around the trees in the rows. His recommendation of Oust for ongoing use was based on it not killing all the soil life and fungi like glyphosate will. It seems like this could be a similar strategy for establishing a tree nursery in general.

Definitely read the labels before deciding to use any herbicide and wear proper personal protection.


This level of targeting is going to be difficult. The list you give here is very open-ended:

With a broad list like that, you will not likely find any herbicide that will kill everything else but not harm any of your trees.


Cardboard and mulch work for about a year. Mowing or weed whipping with a string trimmer helps. Look up Swisher. We have the self-propelled version. I use a battery-op Ryobi hand-held string trimmer closer to the trees and fencing. The Swisher works fairly well on our lumpy, bumpy orchard. A lawn mower would work on smoother ground. The deer and rabbit fencing is a never-ending struggle to keep weed free. It helps if you keep it movable to occasionally mow where it sits. Learn to overlook some weeds between the rows of trees, unless there are close neighbors who might object. Tall grass discourages squirrels, but mowing is better to keep voles and mice away from trees. Pollinators enjoy weeds. I avoid using herbicides. The adjoining ag fields are enough danger for herbicide drift.


That will be more difficult to get control without injuring your trees, but I think I can offer you some help.

For grasses, you might consider Poast herbicide (sethodem). I think the smallest size is 2.5 gal, which will last you a very long time. It’s not restricted use, and you can buy it online. Below is a link. If you shop around you may find it cheaper.

There is also clethodem, which is another grass killer, but I’ve found it not as effective as sethodem (Poast).

As I’m sure you are aware, grasses are the hardest to pull, so if you can kill the grass, that’s at least 1/2 the battle of weeds.

If you spray your seedlings directly with Poast, you could get some yellowing of the leaves, or possibly even kill some, but I doubt it. I use it for my young trees with very good success. Still, you might want to experiment on a few trees by spraying it directly on them, then wait a week or week and a half to see the result. I wouldn’t want to be responsible if it damages your seedlings. But like I say, I’ve not had any issues, even with a lot of overspray on the foliage of trees, with Poast.

It is labeled for all kinds of trees and bushes (since it’s selective for grasses) but I don’t see jujube and persimmon on the label. Probably because they are such a minor crops, no testing was done on those types of trees. It is labeled for peach and plum.

Controlling broadleaf weeds will be harder because your seedling trees are a broadleaf. And because they are young, they are more sensitive to herbicide injury.

As mentioned, glyphosate is lethal to young trees, so I wouldn’t use it around seedlings. It’s a herbicide accident waiting to happen. Glyphosate will stay active in the soil for a while, so if you use it on unseeded plots, don’t seed your trees for at least a couple months, or they likely won’t germinate.

If it were me, I’d try Sinbar as a pre-emergent. It’s labeled for young trees. it’s also available online. I’ve used it for a number of years, mainly on blackberries, but sometimes on fruit trees. It will give good control for about 2 to 3 months depending on the amount of rainfall you get. It kills both grasses and most broadleaf weeds. It will not kill horse weed (i.e. mare’s tail) and a few other broadleaf weeds. But it does a good job overall.

After 2 or 3 months, Sinbar will wear off and weeds will start growing. That’s when you may have to come through with your Poast to kill grasses. For broadleaf weeds after the Sinbar wears off, there are very few choices with young seedlings. You could try something like glufosinate (Liberty). It is not the same as glyphosate (Roundup).

Glufosinate is safer to use around plants vs. glyphosate because it doesn’t translocate to the root zone. It mostly kills what it touches. So if you accidentally get some over-spray on your trees, it will likely kill just what the spray hits. But if you get too much spray on your young seedlings, it still could kill the tree, but I think you’d have to get a lot on the tree to kill it. So just try to keep it off your young trees. As always test it around a few trees before you spray your whole nursery.

I generally use another pre-emergent at this point (along with the glufosinate) at mid season, when the first pre-emergent has worn off. That second application of a pre-emergent, along with glufosinate, will generally take out the weeds for the rest of the season.

Some other good pre-emergents are Chateau, or Alion. But those label restrictions state they want the trees at least a year old or older (depending on the product).

Prowl is another pre-emergent. It prevents seed germination so is safe to use around transplants (but read the label for precautions specific to your situation). I’ve found Prowl better than nothing, but not nearly as good as Sinbar, Chateau, or Alion.

Those are about all the options I can think of for your nursery, but I’m not really a nurseryman. I graft about 100 seedling trees per year, but it’s such a small amount and very close together (like an inch apart) so I generally mulch around them for weed control.

You’ll need a surfactant if you are applying Poast or Liberty. Pre-emergents don’t need a surfactant. You may also need a water conditioning agent to take tie up the cations before you add the herbicide concentrate to your water. Many people use AMS (ammonium sulfate) as a water conditioner. I’ve used it before, but the last few years I’ve been using a Helena product called ReQuest as a water conditioner. It’s a bit cheaper than AMS. It also lowers the pH of the spray water a little bit, which is generally a good thing when using herbicides.

For a surfactant, many people use crop oil. I’ve used various cheap surfactants, which are just spreaders (stickers generally aren’t required for contact herbicides). Spreaders are cheap and simply break the surface tension of the water, so the leaves of the weeds wet easier and more thoroughly. Lately I’ve been buying a water conditioner plus surfacatant (i.e. spreader) combo, called Helfire. It’s about the same cost as purchasing the two products separately.


That’s interesting to hear. I’ve generally heard that cleth does a better job than seth, at least from foodplotters looking to get rid of grasses in clover/alfalfa plots.

I use cleth on my clover/alfalfa/chicory plots and on an acre of wild flowers. It does reasonably well on annual grasses, but perennial grasses generally get knocked back and then show regrowth later in the summer. Maybe I should give seth a shot…

I had heard the same thing from a chem supplier a long time ago. He prompted me to try clethodim instead of the sethoxydim I was using (I miss spelled both chemicals in my earlier post.)

I used cleth for a couple years and didn’t see the control I got with seth. So I was talking with a different chem rep and he told me his cleth brand was better because it had all the adjuvants mixed in which supposedly maximized effectiveness. So I bought his cleth and still didn’t think I got the control of seth. I shared that with him, the next time I saw him, and he said cleth just takes longer to work than seth. But that was not my experience, at least as I remember it.

I watched the cleth very closely and when sprayed at the recommended rate, it didn’t kill all the grasses, only made them sick.

Cleth is cheaper on a per acre basis, because the spray rates are lower. But it just didn’t work as well for me.

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Use tubes around your trees and spray glyphosate (roundup) carefully. Alternate with Glufosinate. About the only way. Keep it off of any part of the tree. Including suckers.

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Absolutely. I lost a small tree when glyphosate was accidentally sprayed on a sucker of the tree.

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I’m glad that sb brought up the question of weeds. Every year we have masses of a weed that has tiny tendrils that spread out below ground everywhere, springing up into new weeds that are killing my fruit trees. I even tried to dig up a 20 foot square section down about 2 feet and tried to pick out the tendrils by hand. Does anyone recognize the photos, and if so can you tell me how to get rid of them. The weed is REALLY invasive.

Most likely Cirsium arvense.


Thank all for the answers. Very important step for me to learn how to control weeds.

It does look a lot like Canada thistle, Nihad mentioned. If you get some older plants later on, it might help give a definitive identification. Sometimes small immature plants can be harder to identify.

It’s not much of a problem in my area. We get some, mostly in the fence rows, or any unmowed areas.

I don’t know if you can regularly mow under your trees, but if it’s Canada thistle, it doesn’t like to be mowed regularly.

As far as I know, it doesn’t give off any special toxins which could be toxic to trees. It only competes with them for nutrients, water and sunlight (if allowed to get tall).

A systemic like glyphosate should do some serious damage to the weed. Just make darn sure you don’t get any glyphosate drift on young fruit trees. I would suggest a wick stick to apply glyphosate around your trees.

Here is one you can make yourself, if interested:

Here is a store bought product weed wiper

Here is a green weeder for larger plantings I bought last year to use around tomatoes. It hooks up to a backpack sprayer.

It works fairly well, and certainly faster than pulling weeds. A lot less risk for non target plants and uses a lot less herbicide. The “sponge” portion of the isn’t holding up super well (and replacements are expensive) but the employee using it last year was pretty rough on it (seemed to feel he had to “mash” the weeds with it). It looks like it won’t be too difficult to make a new sponge portion, when need be, and just reuse the wand and fittings.

Glyphosate will burn the top growth of Canada thistle, but the roots/rhizomes will just send another shot of growth. If you repeatedly kill the top growth, you may eventually deplete the energy. What I’ve found is that the roots look for new ground to expand into instead. Tough plant to eradicate

Thank you. I also reached out to the Maryland Agricultural Extension. Even in the 7 days since I posted my question, the weeds have multiplied 10-fold.

I’ve never seen glyphosate burn the top of vegetation unless there is a second ingredient, which some products use, such as Diquat to speed up the kill process. Glyphosate itself interferes with plant growth eventually resulting in plant death. It sometimes takes 2 weeks or more depending on how actively the plant is growing.