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.
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.
Possibly a shovel and use caution as the tree’s feeder roots will be close.
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.
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.
Yes… this very well might be the case. 🙁
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.
Hi Roger. Likely not. Likely the areas in the tree that are showing dieback will fully dry up. 🙁
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?
I’m following your story. I also have neighbors that spray round up within 2 feet of my arborvitae‘s. They are starting to look brown. If you find anything out conclusively, I would love to hear about it, as I am going to pursue legal action.
So bottom line, I shouldn’t use roundup to kill grass before i mulch around young trees?
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.
This is over a year later, but I was wondering if weedwhacking repeatedly would kill the bellflower? Or weed whack very close and then put down a layer of newspaper or brown paper and then mulch over it?
I have a mixed lawn I don’t mow and I actually hand weed. The year of the maple seedlings was the worst. It might seem like a huge task, but everytime you want to just be outside, sit or kneel and start yanking, or use a weedwhacker.
Hello, my next-door neighbors have used pesticides for 20 years. The inside of my red bud tree is dead. How could I find out if that is from the Roundup spray? Also, my arborvitae‘s that are located approximately 2 feet from the property line are looking brown and they were just planted two months ago. He sprays right up to the property line, how could I get them tested to find out if these problems are due to the pesticides he sprays and pellets he applies?
testing is difficult. Trees do dye on the inside from lack of light. so it may not be the chemical.
Hello. I live in Hawaii and my Hong King Orchid tree is producing a ton on pods that are sprout up all over the yard. I try to pull them up as it is easy when they are small but it’s getting exhausting. Any suggestions?
Maybe a pre emergent?
What is the best way to get rid of poison ivy that is rooted in the ground close to a tree it has been climbing? I’ve got back the climbers, but need to know how to kill or remove the poison ivy so it doesn’t come back!