What are the best chemical to kill tree and shrub roots

achang89(Z6)November 2, 2005

Some weedy trees and large shrubs have been cut to the ground, but I do not want to dig and cause soil erosion. I understand that it is best to apply the root killer when the plants are still active, or trying to obsorb nutrients down to the roots.

Also, should I use the concentrated weed killer, or use the regular diluted one? I currently use the Round-up Brsh killer, "ready to use". I do not know yet how effective it is.

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The best method for killing plants like that are to treat with (a.i.) triclopyr within an hour of cutting. What is in your RU brushkiller?

    Bookmark   November 2, 2005 at 7:18PM
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Rosa(4ish CO Rockie)

Actualy, the chemical will work better on very fresh cuts. When we are working with woody species here we paint the chemical on the stumps within a few minutes for best effectiveness.
And yes, use products that you have to mix yourself (and contains a more effective chemical as in triclopyr), and not ready mixed ones. This way you can apply at a rate that is the most effective for the species you want to kill. the label will have this information for you and if questions, don't hesitate to call the toll free number.

    Bookmark   November 3, 2005 at 7:05AM
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I wouldn't use stump killer products, a copper nail or two in the stump works much better and is a lot cheaper. It has worked every time for me.

    Bookmark   November 4, 2005 at 9:56AM
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The copper nail technique is a often repeated myth. Copper nails will not kill trees or their root systems.

Here is a link that might be useful: ISA: 20 of the most common tree myths

    Bookmark   November 4, 2005 at 10:00PM
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Well, I can't honestly say what if any effect a copper nail has beyond my own observations. But, looking at it from a neutral position I find the statement,

"Not only is a copper nail not only not going to kill the tree, but it is a primary components of many fungicides."

Inconclusive, irrelevant and unscientific for several reasons.

The applications are entirely different. They have not presented any evidence that the copper present in fungicides, which are applied to the outside of the plants even migrates in to the plant, nor have they established the quantities of copper and how they relate to each other. Toxicology is as much about quantities and their applications as it is the material in question. Also, I fail to see why they took fungicides as their evidence. Surely the fact that copper is present in both soil and plants, and that plants purposefully asorb it and use it for biological processes is more revelevant and compelling to the issue?

However, their comparison is particuarly illogical as the copper in fungicides is part of a different compound to the copper in nails. The importance of different compounds is hard to describe without an example. Hydrogen, carbon and nitrogen are a good example. Collectively they form some 31% of the human body's mass, and they're exceptionally important materials without which we could not exist. However, they may form a number of different compounds, one of which is hydrogen cyanide, a very potent toxin that can be fatal in tiny doses. For similar reasons the copper was never the issue, but rather the form it takes.

They have failed to convince me that the copper in fungicides have any relation to the copper in nails, shown no evidence that copper in fungicides even passes through the plant's surface, and they haven't shown any comparisons between the dosage. It may be that the copper in one nail could make several thousand gallons of fungicide, I simply don't know and get the impression they haven't any idea either.

It may well turn out that I'm wrong and they're right about the main issue, if copper nails kill plants, but I would like to base my opinion on more compelling evidence than this.

    Bookmark   November 6, 2005 at 4:47PM
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According to the manufacturers of the glyphosate products they are most effective if applied to the leaves of plants where they are, supposedly, absorbed into the plant.
The single most effective method of getting stumps and roots to be digested is to bore some holes in the stump and fill them with a high Nitrogen product which will encourage the bacteria to get to work and digest that stump.

    Bookmark   July 22, 2010 at 8:08AM
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I have a stubborn tree that is growing in the foundation of my house inside a wall. Because it's inside the house I do not want to usa anything that will be toxic to humans or animals. Any suggestions? Thank you.

    Bookmark   May 15, 2011 at 2:05PM
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A few months ago in winter, I cut a 6 year-old pear tree (in the flower bed). Then I cut through all roots around the stump to mobilize and remove the stump. The hole left by the stump was planted with a new red wood tree.

Now the problem is the strong root system of the pear spreading everywhere under the ground and poping up all over with small new twigs and leaves on the earth surface. I cut the twigs with a bush cutter once a while. But they will become more, thick and stronger. Will they continue to grow, causing nearby concrete damage and messing
up my flower bed and grass? How to kill those twigs and roots, without damaging the surrounding bushes, trees and grass?

Any advice is helpful. Thanks a lot.

Yangming Cao,
Fresno Ca.

    Bookmark   May 30, 2011 at 9:46PM
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Tiffany, purpleinopp GardenWeb, Z8b Opp, AL(8B AL)

Jana and yangming cao, please start your own discussions.

    Bookmark   May 31, 2011 at 8:55AM
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we had a tree cut down and stumpgrinded and now it's roots
are growing in our lawn, how do we kill the roots, or get
rid of the extra growths?

    Bookmark   June 9, 2011 at 10:27PM
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I posted a request in May 2011 for the pear root problems, see above. I did not receive any answer. Then I read other websites and learned to kill the rooting system successfully. Now I receive an email from Debee Deeks for same problems. So I decided to re-visit this web to post a follow-up to share my story.

As I said, the stump of the pear tree was removed. I had to deal with the strong rooting system producing twigs on the surrounding ground everywhere. The more I cut, the worse the new twigs. The chemical I used was Roundup concentrate plus. The detail is "Kill the roots guaranteed. Roundup weed & grass killer. Concentrate plus. Net 32 fluid oz. made by Mansanto Co, Missouri, 2009". I bought this from Home Depot or Lowes or OSH, (dont remember detail, probably Home Depot). The cost is about 10-30 US dollars (dont remember detail). Again it should be Concentrate plus. Also need to buy a pair of gloves that are resistant to chemicals (I bought a pair of black rubber gloves long enough up to my upper forearms). The face mask is optional if wind is not strong. Also needs a clean rag or sponge (I used a small piece of cloth rag). Also needs a porcelain bowl.

Weather and timing: midday, like noon when sun is shining, is the best and when the twig are actively growing. The twig foliage should be dry without being watered or irrigated, (otherwise the chemical is diluted by water). The height of the twigs is best at 1 2 feet. Make sure not to spill any chemical onto the vegetable or other surrounding useful plants. If necessary, may need to separate by a cupboard. Chemical is very strong. Protect yourself. From my experience, the killing will be successful, but dont injure yourselves.


Now wear appropriate garment, mask and gloves. I pour the Roundup chemical into a bowl (to facilitate the handling). Wet / soak the rag in the bowel with chemical. Then rub the rag against the leaves (both sides of leaves) and twigs (all around the twigs) until they are totally wet, from the leaves all the way to ground (dont let rag touch the earth, because the chemical is immediately inactivated by soil). Make sure do this to all the twigs. In a few hours, you will see the change. Usually by 2 weeks, all leaves and twigs die. If there is residual living twigs or leaves, may apply more chemical in 1 -2 weeks to those surviving twigs. And may apply more even some time later until they are totally die, if needed. Even with that, sometimes you may still see one to two twigs coming up the next spring. Use the chemical again. For some superficial roots, you may just dig it out as much as you can. The principle of the chemical is: the chemical is absorbed by the leaves and twigs, then transported by the stems / twigs to the root to kill the root. So for those green twigs, dont cut but use the chemical first. Then later when they are dead, may dig it out if necessary, but many times not necessary to dig.

I applied chemical once, then add a bit one week later, then 4 weeks later for the residuals. This spring I saw only one twig and I physically removed it. No more until now. All the underground roots will die out due to the chemicals and due to lack of sun energy (because no leaves now to take in sunshine).

It is worth trying above. And post your experience later for other readers benefit.

Yangming Cao

    Bookmark   July 22, 2012 at 9:00PM
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Forgot to say the above Roundup has 18% glycophate.

Yangming Cao

    Bookmark   July 23, 2012 at 2:11AM
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Totally amazing how much money people will spend on products that do the same thing as keeping any new green growth cut will do. I have never had to use any kind of poison to keep unwanted growth away simply by cutting new green growth until the roots ran out of nutrients and died.

    Bookmark   July 24, 2012 at 7:43AM
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kimmsr, I agree with you. However, the weed/or whatever it is that I'm trying to kill, is inside my wall, growing from under the foundation. We only discovered it when it started growing out of the light switch on the wall. It's a mystery to us why it continues to grow with no light or water that we are aware of. We have cut holes out of the wall (at the bottom of the wall) in order to get to it. I previously put chemicals on it and it appeared to have died. But we left the holes open to make sure it doesn't grow back. It did grow back, so now have to figure out something else. Because it's inside the wall coming from below somewhere that we can't see or get to, cutting it repeatedly is not an option.

    Bookmark   July 25, 2012 at 2:57PM
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yangmingcao: still following the directions you posted, still keeps coming back so far. I think it's going to take several weeks/months to finally kill this thing once and for all. I appreciate your message.

    Bookmark   September 2, 2012 at 11:35PM
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The key factor here is in the fact it is a tree, which has different photosynthetic properties, etc. Instead of elaborating on why and how things do and don't work I'll get to the point. Use Bayer grass and weed killer full strength it the growth in the wall has a green stem/stalk, if it is wood like or looks as though it has a bark anywhere use Bayer brush killer. Cut it close to the ground as you can, mix per the directions for the strongest suggested concentration and put about 8oz. In a water bottle, put the stem going not going to the ground in the bottle and duct tape it around the top to hold in place until it absorbs it and is TOTALLY dead. Mix some more about half water half Bayer, then pour it on the cut end of the grounded stalk, if you can split the stalk into about four pieces and open them up some first, it won't need much, with about a cup of this pour it at the base of the plant, if the base is unreachable drizzle it down the stalk so that it runs down it and gets into the root source. For the tree problem go to tractor supply or somewhere like that and buy some 2,4-D without other ingredients, it's in the ag chemicals not the regular pest control area, also pick up some 41% Glyphosate again without any other ingredients (meaning active ingredients). Add the amount needed of each into a spray jug then add the water ( yes it is safe to mix these two it's very common for large ag setups). Once you see a sprout spray it, if you don't mind brown grass for a little while wet a circle around it up to a foot or so. If the ground is dry and no rain expected go back the day after you applied it and water it, don't get water on the tree itself though just the ground. If it's hot out or the area drains easily I would do this one a day for about 2-3 days. If there isn't enough moisture the roots have only absorbed a very small about of herbicide if any, the chemicals are still there for several days you just need to keep it moist enough the roots are able to feed. It may take a while to end the problem unsless your very lucky and their are not several different roots going. If that doesn't do it there is stuff that will but it is regulated and you'll have to get someone with a pesticide license to buy/apply it.

    Bookmark   September 16, 2013 at 6:58PM
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