What to do about Japanese knotweed?

Don’t count on juries for your scientific information.


Our property on Vancouver Island had been a rental for decades before we purchased it. Blackberry and salmonberry had had the run of the place; the biggest plants had canes as thick as the fat end of a pool cue. After much sweating and cursing, I came up with a pretty good system. Leather work gloves and an old plaid jacket is de rigueur. First cut the canes into manageable lengths and stack them in a wheelbarrow (to be burned). A mattock really is the tool for the job as you can break up the soil around the root ball and pry with the other end. A shovel doesn’t work nearly as well. It took me a couple years to get rid of the majority of them, but yes there were always a few new invaders to contend with. They are small however and if you stay on it don’t pose much of a problem. We also had plenty of broom, and gorse. Gorse is the worst, after knotweed that is. The city tried poisoning a big patch of knotweed that had established itself in a local park. It came back, angrier this time. Then they brought in an excavator. It’s still there and looking quite pleased with itself.


Come on. No-one who does differentiates between rhizome and root can even think rhizomes without roots. And while we are at it, “co-exist” is not the term anyone who knows what rhizomes are would use.

If you are just trolling, nice try. If you waited for years to get to the level of annoyed by my professional pedantry at to be triggered to write again, then you could have had the experience earlier if you whish.

We are talking bio-containment here. If you are serious about taking the problem at it’s root, you fucking have to fight the rhizome, and it helps to know why. Roots would not resprout.

Now, please excuse me why I deliver my payload to the rhizome of all evil.


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Maybe a slightly-more-modern-than-Carthage variant would work…

A suitably chosen radioisotope could provide sterilizing levels of radiation(one of the water soluble and/or chemically-similar-to-a-biologically-useful-element ones could readily permeate the soil and plants growing in it, avoiding the challenges of getting good root level coverage from one of the less mobile ones like cobalt-60) for a number of half lives; then decay toward background levels.

Not sure if there are NRC-permitted landscapers available; but salinification of arable land is certainly worth avoiding.

Maybe a few of the cold war relics from Project Plowshare are still around? They’d probably love the idea!

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Is this from the alternate-earth version of Fight Club where the protagonist(?) is a deeply disgruntled agricultural extension officer rather than generic white collar?

Because it sounds eerily like that.


This. 1, 2
And with sincere intentions to avoid the posting of a giant list of links:


Under specific conditions wrt local rainfall, soil type and underlying geology, even big molecules like glyphosates tend to not stay put in the soil; instead, these can migrate via stormwater runoff, flooding, etc. to waterways where they affect to aquatic species like fish, frogs, etc.3


So many reasons to avoid its use.

I realize I will never convince ardent glyphosate users here, and I wish you all abundant good health for all your live-long days.

However, in the interest of offering up peer-reviewed, science-based, fact-based evidence re its effects on human health:


The creativity and inspiration behind this idea–wow, I hear you.

What is the plant there for, and what is it trying to tell us? Btw Austin is absolutely awash in ligustrum, and I too found out that

Pretty sure Chinese herbal medicine uses basically every growing thing on the planet. Just a theory.

Peace y’all.

  1. I had a parent (Ph.D., Organic Chemistry) who worked for a chemical company based in St. Louis, in its R&D of a chemical formulation relevant to this discussion. He said some things before he died. I promised him never to repeat the things. I am not repeating the things.

  2. My family has been keeping bees for ten years. We have directly seen the effects of various pesticide use on both local native Texas pollinators and honey bees.

  3. I have worked for an environmental engineering firm for 25+ years, with extensive experience in the fate and transport of various [chemical] elements and compounds through soil, including but not limited to pollution via stormwater runoff.


Sheesh I can barely keep the stuff alive. It fries to death every Texas summer no matter where I place it, including full shade near a leaking hose bib.

For the love of Jah please tell me your secret so I can have your problem. Our bees love nothing better than mint flowers.


I am strongly opposed to the utilisation big glyphosate in farming, but would argue that applied in a responsible manner, it is an important factor fighting Fallopia in your garden.

If you are interested in why and how, and would like to convince me otherwise we could discuss this here.

BTW, botanist & ecologist here, specialist on plant-animal interactions, having worked on invasives, once had (cough, still hold - those things don’t have a due date… sadly) a minor degree in organic chemistry, having some years of experience in landscape planning, ecological restoration, and conservation ecology. Also, been several years on the board of the youth organisation of an important environmental group - that’s been quite a while back now, but left more marks than my OC degree…

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Thank you for this.

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Remind folks, it’s where the very best of those ridiculously expensive Reservatrol capsules come from? It’ll all be gone by this week’s end, and we’ll all be svelte, sexy and youthful forever!


That’s interesting! Thanks for joining up and posting. Welcome to the bbs :smiley:

[I think it’s spelled “Resveratrol”? …I always wondered where the name came from, but never actually looked it up until now…Google is telling me the word itself is from the 1930s and combines the words “resin” and “veratrum” (the plant from which the compound was first obtained) + “-ol”. Now I may have an easier time remembering it :slight_smile: ]


Well they’ve had a robot tell me they’d deleted the comment since I was obviously a Rooski spambot, since I’d forgotton to link to any of Jeff Bezos’ product paged?


Oh dear, that’s too bad. Maybe someone thought you were hawking a product or something? People can be a bit suspicious of new users here, as you might know if you’ve been lurking here at all. I’m sorry that happened.

I would never have known that knotweed is a source of resveratrol if you hadn’t posted that, and now I’ve been happily reading up on resveratrol on Wikipedia… One of the things I love most about the bbs is how everyone knows different things and tosses what they know into the discussion and I learn so much from the other people here. So thanks again!

Edit–the post in question is now unhidden :slight_smile:


Consider reading the comments from the moderator (@orenwolf) in this thread:

And if you have any questions that can’t be answered by the bbs rules, the following thread is the appropriate place:

Thank you. I’d never posted here, previously. Just, I’d honestly wondered if anybody’d seen the irony in a pretty reasonable panic over a green tidal wave of something they were paying a fortune to buy by the milligram? I’d remembered all the blog agreggators doing this, back in 2016, as David Brock’s CTR ended dissent, whistleblowing heros, journalists’ careers and basically, dissemination of true, or accurate information?

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I wonder what you meant, though: were you thanking me for my willingness to discuss, thus asking me to develop my argument? Or do you just appreciate my input that I consider glyphosate to be one element of effectively citing Fallopia in your garden?

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Was thanking you for all your input in this discussion thread.

(would that I had the kind of year-round soil moisture to keep something like Fallopia even alive but that is a kvetch for a different day, surely)

I have several colleagues, whom I love, who work for the [UT-Austin - Lady Bird Johnson] Wildflower Center and the whole operation1 uses glyphosates extensively. Relies on them. So I am familiar with at least my friends’ pro-glyphosate arguments. If you feel like developing your argument in-thread or PMing me, go for it.

Users of glyphosates also include these folks, whom I completely adore and their mission is praiseworthy:
Please excuse their web site, it looks like it’s still 1998 over there but dang they have amazing seeds. Was shocked to learn a decade ago that Native American Seed had been deploying glyphosates as a last resort.

Sorry if I sounded super terse in post previous, we have been getting on-and-off-again flooding and it’s almost a daily occurrence at this point. Lots of time AFK.2

  1. If you’re ever in Austin same time as I am, and if you have the time, I’d love to take you for a walkthrough and hear your feedback. Iced tea and the cost admission on me!

  2. It’s an emergency every frkn day practically speaking.
    The landscape around me, draining itself, has new magic in it when construction, paving, building and developments of massive suburbs replete with scalp-and-top-with-red-death and tons (literally, of concrete, of asphalt, caliche roadbase, etc.) of impervious cover now mean that houses built decades prior suddenly have flooding problems. Not a single regulating authority can be made to care, either, though we have tried.
    A nearby rancher with three generations of family memory on his land was just informed that his 100+ year old house is now, suddenly, in the flood plain. He had called surveyors in to factcheck, as the water in his creek came within 30 feet of the porch of the house in grandmother was born in. Sorry for OT. So it goes.

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Thanks for the invite - not likely to be realised into an iced tea talk, I’m half a world away, my US friends are nowhere near Texas and would have spoken out priority invites. :wink:

No worries, BTW. I understand where you are coming from, but as someone who has seen powerful NGOs fight against the wrong enemy and alienating important allies by absolute stances (and has seen so from the inside!), I like to discuss with people who are strongly opposing things I do oppose for different reasons, and sometimes not absolutely but only conditionally. Genetic modification is such an area, glyphosate another. I don’t want both applied industrially, but I see them as important tools for certain tasks, under specific conditions.

In the case of glyphosate, local per-plant application does the job of killing a plant without killing anything else (mostly), and is less toxic and less harmful than most other alternatives. Any large-scale application, leaf-spraying of a single stand (mostly) included, is a no-go for me, but I know I could be convinced otherwise in specific cases.

Good luck with your dry ground, flooded or not.
Gardening advice from someone I know doing sustainable sustenance agriculture in the Sahel: start mulching, and try to install runoff barriers, e.g. half-moon micro-dikes out of pebbles and stones found in your garden. Given time, life, uh, finds a way. (If you are interested and read french, systeme demi-lune and systeme Zaï might be really interesting search terms for areas as dry and prone to surface floods as Texas.)


A page out of my playbook, entirely. Well-spotted and well-stated! +1!

Author’s training started in Africa, btw.

ETA: Merci beaucoup pour cela


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