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A few years a go, my neighbor had a large weed that was growing next to their house. By the next year, it was as tall as their house. Now several years later, it is no longer a hollow plant; instead it has some type of bark and is very sturdy.

Since this weed/tree is only 10 ft (3 m) from my fence line, its roots have offshoots that sprout in my garden and around my house every year. This year, I tried digging out one of the roots to one of these offshoots, and it took me all day to pull out a root clump the size of a basketball.

Here is one of the offshoots (on the right, next to fence) that I tried killing the year before. I left for the spring and when I came back in the summer, this is what was there.

How do I kill this offshoot at the root?

How do I stop this thing from invading my property every year?

Invasive weed plant from neighbors yard

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    I think you're doing all you can do, legally. You could try digging along the fence line down a foot or two and putting in a hard barrier (like a 0.25" steel plate) that the roots can't penetrate. But they may find a way under that.
    – SteveSh
    Jan 27 at 0:58
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    Well, if you want to bother, you could likely take your neighbor to court to force them to contain it, rather than you having to keep it out, but that's not a question for here, being law. Nuisance plants and noxious weeds, etc... If it's on the correct local list of unwanted plants they might have to remove the whole thing. There's also the herbicide approach, for anything that shows up on your side of the fence. That goes on the foliage, not on the ground.
    – Ecnerwal
    Jan 27 at 1:09
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    Have you discussed this with your neighbor? Maybe getting rid of the whole tree is something you can work together on.
    – gnicko
    Jan 27 at 2:44
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    Since it's just one unobtrusive stem, Why not just chop it at ground level every year? That takes about 10 seconds and lasts for months w/o chemicals, liability, or interfering with your other plants. Or just let it grow and enjoy the grapes.
    – dandavis
    Jan 27 at 2:50
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    12 feet is still easy to chop down; I've done it. Have the neighbor send their landlord a photo, tell them that it's an invasive nuisance, and ask if there is any good reason they shouldn't murder it Better to do this cooperatively if possible.
    – keshlam
    Jan 27 at 5:42

4 Answers 4

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In order to determine how best to control the tree, we need to identify it, if possible. I think I've identified your problem as a Paper Mulberry (Broussonetia papyrifera). It's native to China and hardy in your region; the leaves in your picture are young leaves - you may see differently shaped leaves on the 12 footer next door. The attached link gives us one confirmatory point and one useful point.

This helps confirm the ID: "The tree can be weedy and fast-growing, spreading aggressively by means of root suckers, but it can be pruned when dormant (late fall or early winter) to control growth"

And this provides a potentially useful tip: "it has a shallow root system"

The tree is considered an invasive species across much of the South; not sure about Texas, and when I looked at Texas A&M's site it was terribly unhelpful. If it is invasive in Texas, the landlord may be legally required to remove it (laws on this differ by state).

So, how to control it? You have two options: physical barrier or chemical control. As noted in another answer's comments, chemically treating it may kill the mother tree, which doesn't sound like it'll be a bad thing (especially now that we know what the tree is).

Physical Barrier

I know that this works with shallow-rooted trees and shrubs because I've done it myself. It's a lot of work, but it's one-time work that you'll never have to repeat, and it's permanent.

  1. Find aluminum flashing at a hardware store. I recommend at least an 8" height. While you're there, buy a tin-snip if you don't have one.
  2. Dig a V-trench along the fence-line, with the straight edge of the trench just below the fence. You'll have to dig the trench the height of the flashing minus one inch. Trench the entire length of the fence all at the same time.
  3. Starting in a corner, lay out about 6-8 feet of flashing (more if you have a helper) and begin burying it, a foot or two at a time. Continue until you've buried all of the flashing.

My entire backyard is protected from my neighbors' weeds at this point; this method has saved me countless hours of work and frustration because one of my neighbors has a weed-pit for a backyard, with three different nasty stoloniferous weeds.

There is a possible negative here, specific to the mulberry. There is a good chance that the tree will sprout on the neighbor's side of the fence when its roots hit the flashing, so you could wind up with an unintentional hedge there. Since these are trees that can reach 50' in height, this could become a larger issue and could certainly damage the fence.

Chemical Control

Ignore the posters who recommend RoundUp because it is ineffective on woody plants. The chemical to use is called Triclopyr and it's safer (for you) than RoundUp. It's usually sold as Stump and Brush Killer. Make sure you buy the concentrate, not the already-diluted product. The Ferti-lome brand that I linked to should have a brush inside the cap. It's easy to use - simply cut the stump or stumps to within 6" of the ground, then paint the top AND SIDES of the stumps with the chemical. The tree and all of its roots will die.

Easy, but not as much "fun" as burying the flashing. Not a permanent solution, though, as I expect the tree to return every year.

UPDATE

I forgot to add that you can cut the stump down to ground level a month or so after treating it, if you want to.

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    To expand on the chemical control, Spike 80DF will definitely take care of that weed, just don't under any circumstance apply it to any Oak trees of sentimental importance!
    – Glen Yates
    Jan 27 at 16:31
  • The Picture This app agrees with your identification.
    – isherwood
    Jan 27 at 19:27
  • Yeah, Roundup is nasty business. It's been implicated in leukemia.
    – Harper - Reinstate Monica
    Jan 27 at 22:25
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    @Jasper. According to sources such as National Pesticide Information Center, triclopyr is broken down by microbes in the soil, with a half-life of 8-46 days. npic.orst.edu/factsheets/triclogen.pdf Since it requires about 1-2 tsp to kill a 6" caliper stump, the risks of it even reaching the soil are minimal. I am not recommending that it be used on vegetative matter, only on the stump, so there's no risk of contamination of compost. If you have a better solution, please post it.
    – Jurp
    Jan 28 at 19:45
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    @JimStewart Yes, I'm positive that the plant isn't giant ragweed; they grow to the same heights here in Wisconsin and the leaves look more like dinosaur feet than those. As I noted, they're also much larger than the ones on the tree. The main ID point is that giant ragweed dies in the winter, regardless of hardiness zone - once it sets seed, it's done. One last point - the paper mulberry has two different shapes of leaves. Expand teh photo and look at the 9/10 o'clock position and you'll see the non-lobed version.
    – Jurp
    Jan 29 at 0:37
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We have a non-native invasive tree on our property line in various places. Cutting the trunk at the ground level is a very short term solution, as the plant grows like weeds. My research led me to believe a product such as RoundUp™ would work, but it only delayed the inevitable.

After that period, I read a suggestion to drill into the stump and pour undiluted RoundUp™ into the cavity. It has been more than a year and no sprouts have appeared. Adjacent growths that appear to be branching from the main trunk and are growing in a not-inconvenient direction seem to be living a normal life.

This would imply that the main body on the other side of the fence may not be affected, but that's not a certainty.

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    The stuff actually does work best applied to the foliage as directions indicate. Then the plant transports it to where it will do what it does.
    – Ecnerwal
    Jan 27 at 1:59
  • A lot depends on the foliage (leaves). Roundup doesn't work on things like English Ivy because the leaves are too waxy for the herbicide to penetrate. For plants like that, I think they actually recommend cutting them back then applying Roundup to the exposed stems/stalks.
    – SteveSh
    Jan 27 at 2:34
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    Be careful with this method, if it kills your neighbor's tree you could be held liable.
    – dandavis
    Jan 27 at 2:40
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    RoundUp is very ineffective on woody plants and is only translocated within plants via the leaves. This method is expensive (because you'd need high-concentration product) and very unlikely to work. On all trees older than, say, a couple of years the center of the stump is already dead, with no xylem/phloem and thus no way for the chemical to be transported to the roots. People who anecdotally say this works are typically using it on easy-to-kill trees like conifers, which don't resprout from stumps anyway.
    – Jurp
    Jan 27 at 13:41
  • @Jurp, that's how I understood the instructions on the package as well. Despite that aspect, my results based on an internet-discovered suggestion of drilling into the stump resulted in the incredibly-invasive/resistant tree ceasing to invade. This particular plant is some form of pepper tree and will re-sprout from the tiniest bit of living stock.
    – fred_dot_u
    Jan 28 at 11:13
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I believe this is Giant Ragweed. I have cut it down in a couple of Dallas parks that I do volunteer work at. If this is what you have, it is a native plant, not an exotic invasive.

I am generally not a fan of herbicides and even if I wanted to use one I would not be allowed to on public property. I have sometimes used the cord actuated pruning cutter on a tree pruner to cut these where there is also poison ivy. Otherwise I use loppers or even a pruning saw.

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  • I am in the Dallas area. So this is very useful information. Thank you
    – Spectrem
    Jan 27 at 3:44
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    Sorry, it's not giant ragweed. The lobes on the leaves are too close together and the leavbes themselves are too small. Giant Ragweed is also an annual, so would die over the winter even in Texas.
    – Jurp
    Jan 27 at 12:48
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    Most likely, the tree is pper mulberry. See link in my answer.
    – Jurp
    Jan 27 at 13:43
  • I suppose the general shape of the branching fits the paper mulberry rather than the Giant Ragweed?
    – Jim Stewart
    Jan 28 at 22:41
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We use all natural method, no poison.

Mix Vinegar with some soap (soap is to keep the vinegar on the leaves, so just a touch of it).

Spry on foliage and let it work for day or more.

Might have to repeat the process. That would stop the growth above ground but not the roots.

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    I've tried this too, but it doesn't really kill the weeds, it's about the same setback as weed whacking them. Vinegar takes about 5 or 6 treatments a season, compared to roundup which only takes 1 or 2.
    – dandavis
    Jan 27 at 2:39
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    Certainly not in household use, don't worry. Tylenol will kill you given enough. The cases I've seen were landscape workers who mix gallons of concentrate weekly for years, often under time pressure. Wear gloves and a covid mask if you want to be 110% safe. Another conern with vinegar is that long-term, it can acidify the soil, which promotes moss, which robs good plants of rain and alters the microbial environment, which promotes more weeds...
    – dandavis
    Jan 27 at 2:55
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    Roundup has been adjudicated as causing cancer; the science on whether it does or not is still not settled. Personally, I rarely use it, but I do still use it occasionally. Also, Bayer is removing RoundUp from the US retail market this year due to the ongoing lawsuits, so this will be a moot point in a year..
    – Jurp
    Jan 27 at 12:50
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    @DonBranson RoundUp? Well, there is a recent study showing 85% of people in the US have glyphosate in their urine, probably because we're eating it in our food. usnews.com/news/health-news/articles/2022-07-12/…. Glyphosate remains in soil for at least 6 months but then breaks down: "Glyphosate binds tightly to soil. It can persist in soil for up to 6 months depending on the climate and the type of soil it is in. Glyphosate is broken down by bacteria in the soil" see here: npic.orst.edu/factsheets/glyphogen.html#env
    – Jurp
    Jan 29 at 20:27
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    @DonBranson - In case you care, I was a certified pesticide applicator in Wisconsin for 5 years. This involved taking a fairly detailed test about different products, means of application, means of disposal, protective equipment, etc. As a result, I NEVER use ANY pesticides in my vegetable garden. It's not always about the chemical, it's also what it breaks down into. I'm not positive that glyphosate breaks down into bacterial metabolic products; many "safe" herbicides break down into carcinogens, so better safe than sorry, IMO.
    – Jurp
    Jan 29 at 20:35

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