Will Roundup Kill A Tree?

Will roundup kill a tree? As a property manager, I have tried many ways of how to kill a tree. Roundup is one of them. Here is what I have found.

Roundup will kill weed trees but not large trees without some additional chemicals. I found that trees under four feet will die when the leaves are sprayed but anything larger than that will not die.

How To Kill A Tree With Roundup

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A few years ago I tried killing several trees with roundup. I tried spraying the leaves of some large tree stumps that had shoots coming out.

I even cut a tree down to a stump and drilled holes into the outer cambium layer of the tree and filled the holes with roundup. Both of these attempts did not work. The tree came back with a vengeance.

The one way that has worked for me is to spray weed trees with roundup just like a weed. 

When the tree doesn’t have a well-established root system then just spraying the leaves with roundup will kill the tree.


Not all trees need to be treated to die.

There are many trees like palm trees and pine trees that only need to be cut down to die. Once cut down below the branches these types of trees will die roots and all. 

I made a full list of trees that need to be treated and trees that don’t. That way you can save yourself the time and money and not treat trees that dont need to be treated.

Some trees are more resilient than others and the current health of the tree can also effect if roundup will kill the tree or not. So roundup may kill your tree but it didn’t kill my well-established elm trees.

Since this first attempt to kill trees with roundup, I have done a lot of research on how to kill trees. In my searching, I found a recipe from the Utah Ag Extension that uses roundup and will kill even the toughest trees.

Roundup Tree Killer Recipe

Roundup by itself won’t kill large trees but if you mix two other chemicals then it will. Here is the recipe I found from the Utah Ag Extension:

After mixing these three ingredients together here are the steps to kill a tree with roundup.

  1. Cut the tree down to a stump. 
  2. You can drill holes into the outer cambium layer of the tree. (Its the outer lighter ring.) However, you don’t need to do this. 
  3. Paint Roundup onto the tree’s cambium layer or outer ring just inside the bark.
  4. Let sit for several days and then remove the stump.

How To Kill Weed Trees with Roundup

Roundup works great on weed trees. At my properties, I have tons of weed elm trees popping up every year. I am quickly able to get rid of all of these weed trees by mixing up some roundup in a gallon sprayer. 

It’s simple. Just follow the instructions for mixing roundup. You may want to mix it a bit stronger for trees than normal weeds. Spray all the leaves of each weed tree. In a few days, they should all be dead.

In less than 20 minutes I can kill all the weed trees on my property this way.

Will Roundup Kill A Tree Stump

One thing most people don’t realize is that a tree is as big below ground, as it is above ground. When you cut a tree down to a stump it doesn’t always mean it’s dead.

When I have cut trees down to a stump without killing them I can expect to see huge sucker branches growing up very quickly. It’s actually quite amazing to see how fast they can grow. 

Thats why the stump needs to be treated with a tree killer when it is cut down or it will just grow back. Roundup by itself is not strong enough to kill a tree stump. If you use the recipe mentioned above then round up will work. 

Unless you have those products already lying around the house it makes more sense to just buy Tordon or Fertilome Brush and Stump Killer. Both of which I have tested and kill tree stumps very well.

They are a third the price if you bought all three products in the recipe.

Can You Kill Grass Around A Tree With Roundup Without Killing The Tree?

The answer is yes. But you have to be careful. I have a friend with a lawn care business who always uses roundup to make tree wells around his trees.

It saves him tons of time from needing to string trim around each tree and it is healthier for the tree. He will spray each tree well twice a year and that’s all it takes.

He says, however, that you need to be careful not to spray roundup on the tree over and over because it can make the tree unhealthy and could kill it especially on younger trees.

So will round up kill a tree? By itself just baby ones. If you want to kill large trees with round up try the roundup recipe or just get a good tree killer.

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