That's a tough question, Queuetue. And one I've personally wrestled with many times over the last three years while pulling hundreds of knotweed shoots from the gardens here.

One thing that's held me back from using chemical poisons on the shoots is the possibility the poison would reach the motherplant in a neighbour's yard. They like their knotweed. Entirely outside of the legal issues of killing off vegetation in someone yard, I don't like messing with plants growing in another person's garden.

Think you have to decide for yourself. However, the description of this GW forum -- Organic Gardening -- reads "This forum is meant for the discussion of organic gardening. Organic gardening is most easily defined as a philosophy that stresses the use of naturally occurring substances and friendly predators and avoiding man-made chemical fertilizers and pesticides. This is the philosophy which guides this forum." (emphasis added)

All the best,
-Patrick

p.s. Japanese knotweed does have one natural enemy: humans. Apparently the young shoots are edible, though I've never tried eating them.

If I had a big poison ivy problem (and I couldn't rent a herd of goats), I'd use Round-up. I wouldn't say so on the organic gardening forum, though :-).

"Lifelong battle" probably would not reach the resorting-to-Round-up threshold. Of course, that's easy for me to say; I don't have Japanese knotweed...

Whether it is justified is 100% up to you.

If you want your land certified for organic crop production then you need to obey the rules of the certifying agency.

If you want to appease some group/club then ask them.

If you want to garden responsibly then consider the issues you are dealing with and then choose the least toxic means of dealing with the problem that is a. likely to work and b. something you can handle.

Biting off more than you can chew is a good way to get garden burn out and everyone is different.

In my experience, Roundup is the only solution that has worked for certain very difficult weeds. Even persistent, years long weeding has not controled some of the very tenacious weeds. In contrast, one or two quick applications of roundup has done a good job. In my estimation, the massive savings in time and labor, along with the unsuccessful other routes justifies the roundup. Each person has to make their own decision. Note also that there is likely more than one plant, and even if some of the plants in your neighbor's yard are killed, they are likely to be replaced with others in their yard. Maybe someday there will be a purely organic solution to the tough weed problems. Unfortunately, I have yet to find anything that comes even close to roundup.
Renais

I'm envisioning Japanese knotweed as the equivalent of Bermuda grass, which spreads by underground runners (stolons) even in dry conditions/poor soil/darkness and is *very difficult* to eradicate. However, I have eradicated Bermuda grass in the past and KEPT IT AWAY for 10 years by sifting the dirt through a 1-cm screen for root sections and throwing them away. In your situation, I would ALSO put metal flashing down to at least 8 inches (approx. 20 cm) deep to keep new runners from intruding. Good luck!

I don't think 20cm will do it - I've personally pulled 5 or 6 feet of 1-2 inch thick roots from 4 feet deep in the ground - in an area that didn't even have any shoots showing.

Thanks to everyone for the advice. I don't have a course of action yet and "my side of the fence" is under control at the moment (cardboard and mulch, I'm going to try to lasagna it out. If it shows up in this spot again, I'll try gravel.) - my concern is for what will pop up in the future, how proactive to be, and how I should address it when it becomes a full blown crisis.

Those thick roots probably run the entire 20 foot distance from where I ripped them up back to the mother plant - directly under my garden, so I'm just prepping myself to deal with the worst.

It is up to you. As an organic gardener you ae supposed to be making the world, or at least your part of the world, a better place for future generations and if you can justify using these kinds of poisons in that philosophy, you can use them. However, many of us think there is no good reason to ever use those poisons.

People always mentioned, in defense of RoundUp, that years of weeding hasn't rid them of an invasive. No, weeding doesn't work well, but smothering mulches frequently do.

Organic gardeners don't use RoundUp. I don't call myself an organic gardener, not because I use RoundUp, which I don't, but because I use OPGCs of unknown origin.

OK, Annpat, I've racked my brain (or the variant "wracked") and perhaps it was the glass or two of admittedly cheap Chardoney, but what the heck are OPGCs and should I worry about them spreading from your garden over into Western Maine?

And to queuetue, no, chemical herbicides are never justified if you consider yourself an organic gardener. (Time again for us to do a basic reminder search into the principles of organic gardening.) Use mulch and other physical, impervious barriers to blockade your garden and rightfully defend yourself from your neighbor and his pest. If necessary, tell your neighbor you will stop blaring noxious Metallica CDs at his house 'till all hours of the night if he will stop growing that evil, invasive weed. Heck, it drove Noriega into surrendering down in Panama. It should work on a simple, ignorant gardener in love with a noxious weed. What! You're not blaring Metallica at his house 24/7 ?? What are you waiting for? Those roots are creeping towards you every minute!

I successfully fought off bindweed, which has roots that penetrate the soil forty feet or more deep, with mulch and hand pulling (no Metallica necessary), and somehow managed to survive on my vegetarian diet for years, mostly from the produce of the garden. Now that I moved to Maine and have started a new garden, I just now see the same heart-shaped leaves that plagued me in the Adirondacks appearing in the new garden beds.

I am not afraid! I have mulch and I can get my hands on a copy of Metallica, The Black Album!

Wayne

OPGC = Other People's Grass Clippings.

(While we're at it, OPBL = Other People's Bagged Leaves. (And while we're REALLY at it, I think that UCG, which = Used Coffee Grounds, is silly. Coffee grounds are by definition used. Ground coffee pre-coffee, coffee grounds post-coffee.))

Alfie,
compost lexicographer

From what I have heard, chemical herbicides do not work to control japanese knotweed. It can grow through 6 inches of highway pavement. I have this info from someone who works for the DOT. In my state, japanese knotweed is growing along many creeks and turning into huge monocultures, sort of like purple loosestrife, only on land. If it were my yard, I would just keep mowing it down over and over. What else can you do?

You've been misinformed. While Japanese knotweed has tremendous root reserves and is difficult to control even with herbicides, huge numbers of acres have been cleared of this weed successfully with proper applications. As for mowing, it actually makes established clumps of this particular weed spread out more rapidly. Smothering for multiple years can work however, where this technique is feasible. Heavy, flexible barriers are needed.

Iron sulfate solution (ferrous sulfate, copperas) and strong acetic acid solution are sometimes used as herbicides, and are chemicals and synthesized, but both chemicals occur naturally: the iron sulfate as a mineral and the acetic acid as vineger (less strong, of course). The answers are not always straight-forward. They don't kill roots though, so it is a moot point here.

Although I don't sell my produce or have Certification, I consider myself an organic gardener.
I bought and used Round-Up once ( over a season) in my life because of Japanese Knotweed. It was painfully obvious that traditional methods were not working toward its eradication.Not mulching or weeding. Digging it up works, but absolute diligence is required to get every tiny shred out of the ground. Mowing is a good way to spread it- ask the township road crew.Sieving one yard of dirt will remove your sanity if you have another 10,20, or 100 to do.
So I just want to help you get rid of it and leave you to ponder credos on your own.
Using glyphosate on your intruders won't kill your neighbor's plants, and won't kill yours unless you sever the connectors. It will stunt growth for a bit if you don't.
To eat the shoots, pick at 3-4".I tried them raw and stir fried. Meh.
It is related to buckwheat. No wonder that leaf looked familiar.

Being an organic gardener has little to do with being certified but has a lot to do with personal integrity. If one claims to be an organic gardener but does use one of the "weed" killers then that person should not, at least here claim to be organic for the number of years after using that it takes to clear it from the soil, at least 5.
If the glyphosate products won't kill the plants, alphonse, why bother to use it?

Selling produce/dairy labeled "ORGANIC" has a LOT to do with certification, at least in the states where I've talked to farmers who either do or tried to.
We could have pages of debate about this, but some of the prior posts allude to it: how do you know whether OPBLs, manure or any other off site input meets big O organic requirements? I'm not jumping through those hoops to be Organic, but do the best I can as sanely as possible.
Perhaps I wasn't being clear enough,glyphosate WILL kill polygonum cuspidatum, but only by observing certain criteria. If anyone has anything that is as effective in an "organically" compliant way I will be happy to proselytise.My concern is eliminating the plant, not promoting bees in bonnets.
My infestation and subsequent poisoning isn't near my garden. But there again we have an issue of relativity-if a forty acre Organic farm gets forbidden overspray from a non-compliant neighbor, do they lose their certs? For 5 years?

Well, it sounds like another re-write of the "Principles or Organic Gardening" at work here. Pretty simple, it seems. Alphonse wants to use Roundup to solve a problem and still call himself an "organic gardener."

The folks who write the "rules" that many of us ascribe to and do not knowingly violate say that organic gardeners will not use Roundup.

It's a lot like being just a little bit pregnant. You either are or you aren't. If you decide to sell one "organic" tomato, then you had better meet all the criteria. We here may have our opinions, but you are not engaged in commercial agriculture, so just do what ever you think is right for you. You're not the only "organic gardener" I've seen here and on other forums that uses Roundup. What they call themselves is unimportant to me, though, as Kimmsr rightly points out, it has a lot to do with personal integrity.

Just be aware that a lot of people here won't be swayed. This is, after all, an Organic Gardening forum.

Wayne

Ok, here on my 3.5 acres, I grow my vegetables 200 yards away from the 40 acres of over-grazed, invasive weed (Russian knap weed, yellow toad flax, 3 kinds of thistle, bind weed, fox tail, cheat grass and saddle burr, at last count) patch that belongs to my absentee, little-old-widow-lady-in-an-assisted-care-facility neighbor, and this patch being up wind from my place, and I get approx 7,465,987 weed seeds / season blowing in from there onto the my place, clouds of the stuff from about now until November, and I go over and nuke some of it now and again with RU and Weed Master to try and keep it from Taking Over The Whole World, but follow organic practices on my veggie patch and orchard and everything else, am I an organic farmer?

No. But I'm a big fan of yours anyway.

:-)S

IMO, roundup is safer for people and for the environment than strong acetic acid is, yet one is considered acceptable by organic gardeners and the other is not...I find it ironic.

Vinegar does not occur naturally it is distilled/fermented.

I use chems on poison ivy.

Fermentation is a natural process. The percentage of acetic acid that's in white vinegar is not that much different from the percentage that's in wine vinegar, which anyone can make by just leaving a bottle of wine open until it sours. You don't have to distill anything. So it is, in fact, pretty natural.

The "strong acetic acid" that is recommended for gardening purposes is not normal vinegar.

>IMO, roundup is safer for people and for the environment than strong acetic acid ....I use chems on poison ivy.

I think I'm beginning to understand why so many people who don't believe in God go to church. So they can tell their friends that they're religious. Either that or they like the singing.

I guess one doesn't have to believe in the basic principles of Organic Gardening to hang around here.

Wayne

...Now please turn to Hymn 103 'Our Master Hath a Garden.' And you tenors in the back, don't even think of messing with that Roundup! Remember what happened to the last ones who messed around in the garden..."

There is a different perspective from those who live amongst and enjoy the vast federal lands in the west and see the ecology-changing devastation of noxious, exotic, invasive weeds. Easily the single worst risk. Millions of acres of cheat grass, changing the sage brush ecosystem into a Tibetan short grass ecosystem, tamarisk changing thousands of miles of river corridors into a nearly sterile mono-culture, and so on.

Anyone is welcome to bring out their excess card board and smother away - :->S.

Well, that's the thing. I, personally, me, Alfie, speaking only for myself, in my own garden, am an organic gardener. (I think that even Kimmsr would agree. I don't know about Annpat :-).) However, that doesn't mean that I think that nobody should ever use any synthetic chemicals whatsoever under any circumstances anywhere. Conditions and people both are much too varied for me to feel happy with such a general pronouncement. If somebody does use some synthetic chemical somewhere, under some circumstance, it's not organic gardening -- but that doesn't necessarily make it a bad thing. It might even be, in the big picture, a good thing.

(Shoot, I'm even of two minds about whether or not my mother-in-law should use Round-up to try to get the Bermuda grass out of the mondo grass around her pool. (Luckily, she didn't ask me.) On the one hand, Round-up, bleh! (And does it work on Bermuda grass anyway?) On the other hand, she's not as young as she used to be, it's a billion degrees with 300% humidity by 9 am, and there are flocks of mosquitoes.)

Organic gardening isn't a religion. Organic gardeners aren't the saved. But: organic gardening is a defined something, and the definition doesn't include using Round-up.

I appreciate all of the differing opinions. I wouldn't ever call myself an organic gardener - I make as many organic choices as I can, but I don't know the pedigree of that bagged compost I needed this year, or the history of the random bags of lawn waste I pilfer from the curb. I don't know if the Murphy's oil soap I put on my aphids is organic and some of my seedlings didn't come from the local organic coop. I do try, but whether I use roundup or not (and I haven't yet) I'm certainly not an ordained organic gardener - just someone trying to make the best choices I can for my home and garden.

That being said, I'm glad I asked this here - most of the other forums wouldn't even get why I was asking, and I got a lot of useful opinions. I'm still no closer to an answer, and I've had to cut clusters back twice since I originally asked the question, but you have helped me think through my options better.

Wayne, do you think strong acetic acid (the 20% kind sold to gardeners) is safe to use?

I'm not talking about whether its certified organic or not, I'm talking about safety...

Too much religion is just as bad as too much of anything...

All things in moderation, eh?

david52 actually can be considered organic, according to certificaiton standards. The required buffer between organic and conventional fields that are part of the same farm is only 25' (roughly 8.5 yards). Therefore, his 200 yards that separates the weed patch from his garden is more than sufficient for his veggies to be certified organic.

Ah. Thats good to know.

As an aside, Colorado has a few laws on the books about "officially noxious" weeds - the land owner is responsible for controlling, or at least trying to, control them. It isn't enforced all that often, witness the millions of Russian Olive trees, but this particular patch has two of the worst - Russian knap weed, which is toxic to horses and there are a whole lotta horses around here, and some kind of velvety leafed thistle, that has spines on the leaves that will go through a pair of leather gloves like a hot knife through garlic / herb butter at a Fru Fru, fern adorned restaurant.

Interestingly enough, I woke up this morning and the knotweed was missing from the neighbor's garden - all of it. There was also some light digging. Apparently, the landlord across the fence didn't like it overtaking their lawn either, and had their gardener pull it.

Hopefully, this knocks it back, instead of causes it to spread like some sources have told me it will. At least I now know I won't get in trouble for attacking it, organically or otherwise.

Being judged as lacking integrity by the readership here won't bother me too much, and there is no need to darken the doorway with further posting.
Queuetue, I hope recent developments make your life easier.

I was thinking about this before I saw this thread and the question that occurs to me is " Does Global Warming trump Organic Gardening Principals?"
If every action we take has a small bearing on our carbon foorprint is this not of greater importance?

So for the sake of argument if using RU means we avoid other actions that contribute to Global Warming (I am not saying it does butI suspect it might if used responsibly) and so on balance is a good thing then maybe the "rules" for Organic Gardening have to be rewritten.
These "rules" can be rewritten once the Global Warming emergency is over (or we are)

I was having a similar internal dialog last night while watching Geoff Lawton's We Are The Weeds - thinking about how the extraordinary damage we've presented to the ecosystem will require extraordinary means to repair it.

Of course, his story seems perfectly organic - reclaiming salted land near the dead sea using OM and taking advantage of the land's structure in retaining and utilizing water, but it did make me wonder if the tremendous energy spent in forming the world into what it is isn't going to take an equal amount of energy to get it back to something stable, and what form that energy will take, if not a wiser and more judicious use of some of the same methods that screwed it up.

I'm not trying to justify my original question here (and I still haven't bought the roundup. :) ), but I wonder if there is a practical solution to the places overrun with invasives that doesn't involve either chemical intervention or a million years of evolution. Or if there is a practical way to reclaim enough ruined topsoil while simultaneously still feeding the planet using only the compost and mulch that exist.

It's certainly not within the forum's mandate - it wouldn't be organic gardening, and it wouldn't be sustainable or natural, but with management and forethought, it could be a reparative step used to get us to those goals. This is a slippery slope, though - everything that got us to here was done with innocent, sometimes even laudable intentions. It's the lack of proper foresight that got us into these current messes. I'm not suggesting yet another shortcut, just wondering if it's the only way left out.