ZigaForm version 5.2.3

Will Roundup kill my trees?

As an ISA Certified Arborist I get to look at a lot of trees and how they are affected. Many times I hear clients asking Will Roundup kill my trees? or, “Will weed killer kill my trees?”

There’s been a few times in my career since 1997 that I’ve seen clear evidence of weed killer killing trees. This was one of them from last week.

Basically, my client had used “Roundup Extended”, or “Roundup X” along his path at the base of the tree. He had used it liberally within at least half or more of the tree’s critical root zone.

The client had called me to ask what was going wrong with his tree as it was not thriving as it had in years past. He had never used round of tax prior to this past season.

The thing that was so striking about this example was the pattern of die out in relation to the path. Basically, he sprayed the path in between the tree and the house. Typically speaking right side roots feed right side branches and left side roots feed left side branches. Looking at the die-out pattern of this tree, the only place that did not look affected was the section directly over the grass but did not get sprayed.

Mode of action
The way that weed killer enters planty material is called “mode of action”. Certain chemicals are uptaken within the roots, others can soak in through the bark, others have to be injected directly into the tree system, and others enter in by just touching the leaves of the tree or plant.

Roundup’s mode of action is supposed to be through the leaves. There is a possibility that the roots of this tree grew small suckers which the client sprayed with Roundup and the tree took in the chemical that way. However, there is also a possibility that the tree took in the chemical through the root system or by directly spraying it on the trunk.

In some of my continuing education classes I have heard discussions of different cases where Roundup extended, or Roundup x, and the specific chemicals within this product vs normal Roundup, are affecting trees in a negative way.

My suggestion is not to use Roundup X. After hearing different arborist discuss different examples of this specific product killing trees, I think it would be more prudent to use a different product.

10 thoughts on “Will Roundup kill my trees?”

  1. I am trying to kill some Jasmine Ground cover which I regrettable planted some years back. There is way to much to dig out on my own. I have a few ornamental trees in the same bed that have been there for quite a few years. I was going to use roundup but after reading the above I am leary. I was going to use a spray pump to avoid it going anywhere but on the ground cover. Any suggestions.

    1. My husband used Roundup on suckers at the base of a lilac tree and now the tree is dying…….DONT DO IT! It is a twenty year old tree….,so sad.

  2. My Chinese Raintree has not set leaves as yet and I’m quite sure in looking back that spraying suckers around the trunk has harmed the tree if not killed it. We are talking about a ten year old specimen.

  3. Can I save a tree that seems to be dieing ?
    We used ROUNDUP for Lawns a few weeks ago
    and now 2 of my very large maple trees are
    showing signs of dieing. The leaves are turning
    black and many of them are falling off. I saw
    dead leaves on the ground under the tree
    and upon closer obersvation, the entire tree
    is full of black leaves.

  4. Carl P. Forbes

    Hi Mark,
    I had a row of poplar trees 30 or 40 years old and my neighbor sprayed weed killer on the ground maybe three feet away from them every spring. I began to lose a couple and started watering in the summer but they’ve all died now except a couple and they aren’t doing too good. Is there any way of knowing if week killer is the cause of the trees dying?

  5. Elizabeth Crandall

    Over the past 2 years, we’ve had a ton of Creeping Bellflower appear on my father’s property, and he has a lot of trees. I take care of the property for my father. The next door neighbors, who we’ve always been quite friendly with, are avid gardeners and have asked us to remove the Bellflower – as it is rapidly growing out of control. I want to get rid of it as much as they do, now that I’ve learned more about it. It’s already making its way into the lawn and away from the fenceline. Its highest concentration is along the fence, though. Along the fenceline, we have some shrubs and an already somewhat blighted looking large tree. I’ve tried spraying the Bellflower with vinegar/soap solution, I’ve tried smothering areas, nothing is working. My research is showing over and over that Glyphosate is the only real solution, and that even digging deep down at this level of infestation will probably not solve the problem. To complicate the issue, the previous homeowners put in rock filled borders all along the yard. The rocks are near impossible to remove now. If you put a shovel into the ground anywhere in the yard, you will hit rocks. I think for decades these rocks were piled on top of each other as the soil eroded and the old garden beds began to look shoddy. It would cost thousands for me to hire a company to remove the rocks and replace with mulch.

    The bellflower is infringing on the area around the already sickly looking tree, and lots of shrubbery. I need to kill it off before we lose our good relationship with our neighbors or worse, are cited for it by the HOA for not removing it (it is spreading under our fence between the two properties, though neither of us know where it originated, but it is EVERYWHERE). Can I expect everything including our big tree to die? I would never apply it to the bark of a tree, though it’s began to encircle the base on one side. My experience with “Painting herbicides onto leaves with a brush” has resulted in a TON of trouble for no effect at all. And I mean NO effect. Just not sure what to do and want to get it under control before the hot months come on and before our neighbors get less friendly about the issue. It’s clearly become a big source of frustration for the neighbor I like the most! Just not sure what to do or if my efforts are going to leave a wake of destruction beyond the horrible terrible Bellflower.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top