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Japanese Knotweed - how to kill?

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    #2
    pedigree 6
    Closed Accounts Posts: 4,559 ✭✭✭pedigree 6


    Grazon 90 will kill it.


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    #3
    yosemitesam1
    Registered Users Posts: 2,948 ✭✭✭yosemitesam1


    Roundup will kill it too, but don't go near it yet. Wait until mid to late August to treat it and get the best kill, if you go before the plant starts sending food back down to the roots for winter you won't get full translocation of whatever you spray and it'll be back


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    #4
    kay 9
    Registered Users Posts: 2,668 ✭✭✭kay 9


    Takes 7 years to kill it off completely they've said here in Galway. People have been told not to cut or spray.
    Apparently the stem needs to be injected but that seems like a prick of a job.


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    #5
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    Nothing will kill it in one spray if its well established. Consider getting rid of it a long term project.

    I'd spray asap with whatever you have now, grazon 90 or anything glyphosate based and again when it regrows at the end of the season.

    Then next year follow up with a dose in May and another in early September until its gone.

    In subsequent years keep an eye on the area and spray any regrowth.

    Even if it seems to have died out avoid disturbing the soil in the area as damaging the roots can stimulate it back into growth.

    The September spray before the leaves die off is the most effective because the plant takes any available nutrients and the herbicide back down into the roots over winter. However a spray early in the season can keep the height of the plants down so you can get at them all in September. If near a drainage ditch or water then glyphosate with a clearance for aquatic use is the only choice.

    DO NOT trim the back the JK in the hedge as it roots from the material you cut off and may be why its spreading at an alarming rate.


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    #6
    Markcheese
    Registered Users Posts: 8,431 ✭✭✭Markcheese


    I've sprayed a bit on the boundary ditch... Then burnt it in spring and gave another couple of sprays of roundup through the year... Think i got most of it now...

    Slava ukraini 🇺🇦



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    #7
    Kristopherus
    Registered Users Posts: 11,907 ✭✭✭✭Kristopherus


    my3cents wrote: »
    DO NOT trim the back the JK in the hedge as it roots from the material you cut off and may be why its spreading at an alarming rate.

    Is that why we're seeing a myriad of small signs on roadsides now saying "Japanese Knotweed. Do not cut"


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    #8
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    Kristopherus wrote: »
    Is that why we're seeing a myriad of small signs on roadsides now saying "Japanese Knotweed. Do not cut"

    Thats it. The coco's used to flail mow it in the hedges and are responsible for spreading a good bit of it themselves.

    Worse still the heavy tread on the tractor tyres can plant the cuttings when they run over them on the verge giving them even more chance to survive and grow.

    In other areas like ours by the side of rivers and near the sea it washes down stream growing in the banks where it ends up and even gets washed up on the beach and grows but in that case its the roots that are the agent that propagates it.


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    #9
    dryan
    Registered Users Posts: 493 ✭✭dryan


    Any spray out there that will kill the JK but wont kill my beech hedging?


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    #10
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    dryan wrote: »
    Any spray out there that will kill the JK but wont kill my beech hedging?

    No, but you can inject the JK stems with glyphosate.

    You can buy a tool to inject the stems, cheapest one is about €100 or you can do a DIY method with a large syringe and large gauge needle. The trick is to make a hole in the correct part of the stem first with a small piece of wire or a cocktail stick otherwise making the hole with a std needle just results in the needle blocking up.

    You can look up the application rates and where exactly to inject the stems online.


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    #11
    _Brian
    Registered Users Posts: 18,510 ✭✭✭✭_Brian


    kay 9 wrote: »
    Takes 7 years to kill it off completely they've said here in Galway. People have been told not to cut or spray.
    Apparently the stem needs to be injected but that seems like a prick of a job.

    It only needs injection if it's growing on a river bank and can't be sprayed.

    I've read that August/ September is the best time to spray, and spraying with roundup is fine. Repeated sprays will be required.

    Came across a huge stand at work this week, maybe 1/3 of an acre and 12 ft tall.


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    #12
    Base price
    Registered Users Posts: 11,180 ✭✭✭✭Base price


    When I was doing my spraying course (hand held) there were a couple of lads who did contract work for the County Council. They were using a product called Synero for japanese knotweed. They said that it has been trailed n NL and GB over the last 5 years with good success. They said that knotweed has rhizomes (as opposed to a root system) which can be as deep as 15 foot under ground. As yosemitesam said timing is crucial when spraying/injecting, apparently Autumn is the best time so that the pesticide can be carried with the sap to the rhizomes.
    http://uk.dowagro.com/products/synero/


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    #13
    pedigree 6
    Closed Accounts Posts: 4,559 ✭✭✭pedigree 6


    Nom, Nom, Nom and Nom......... And Nom.:D



    Edit: Chà Ching!


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    #14
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    Base price wrote: »
    When I was doing my spraying course (hand held) there were a couple of lads who did contract work for the County Council. They were using a product called Synero for japanese knotweed. They said that it has been trailed n NL and GB over the last 5 years with good success. They said that knotweed has rhizomes (as opposed to a root system) which can be as deep as 15 foot under ground. As yosemitesam said timing is crucial when spraying/injecting, apparently Autumn is the best time so that the pesticide can be carried with the sap to the rhizomes.
    http://uk.dowagro.com/products/synero/

    But the problem is that synero is for non-crop area only which means you can't use it on a hedge row without killing the hedge.
    For the control of a wide range of deep-rooted PERENNIAL and HERBACEOUS WEEDS on NON-CROP LAND such as motorway and railway embankments, roadsides, grassland of no agricultural interest, and industrial areas (but excluding airfields).


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    #15
    Base price
    Registered Users Posts: 11,180 ✭✭✭✭Base price


    my3cents wrote: »
    But the problem is that synero is for non-crop area only which means you can't use it on a hedge row without killing the hedge.
    I think it refers to its use for food crops.
    I'm sure that there are other's on here that have come across it.


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    #16
    patsy_mccabe
    Registered Users Posts: 10,707 ✭✭✭✭patsy_mccabe


    Is this it?

    'When I was a boy we were serfs, slave minded. Anyone who came along and lifted us out of that belittling, I looked on them as Gods.' - Dan Breen



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    #17
    SmartinMartin
    Registered Users Posts: 2,937 ✭✭✭SmartinMartin


    Yes. A lot of info here;
    http://invasivespeciesireland.com/toolkit/invasive-plant-management/terrestrial-plants/japanese-knotweed/


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    #18
    50HX
    Registered Users Posts: 1,705 ✭✭✭50HX


    patsy_mccabe wrote: »
    Is this it?

    that's it rotten stuff

    they had to dig a huge site in london when they came across it building the Olympic village

    as in a previous post there is a window in early sept to spray it

    have it here with 5 years and spraying is just about keeping it under control never mind kill - know another lad who has it longer and sprayed with various stuff

    the forestry companies use to use a product that is ment to do the job but i think it's now band

    i have been told to use I-CADE

    ment a guy on a course one day and he was telling me he was nearing the end of completing a stone wall around the farmland boundary that his grandfather started back in the early 1900's and came out one morning to find a section of it after giving way coz of the JK


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    #19
    patsy_mccabe
    Registered Users Posts: 10,707 ✭✭✭✭patsy_mccabe


    Feck it anyway. Only last week cutting a privet hedge on the farm/yard boundary and a relative said to me that it was Japanese Knotweed. Never knew I had it.

    'When I was a boy we were serfs, slave minded. Anyone who came along and lifted us out of that belittling, I looked on them as Gods.' - Dan Breen



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    #20
    50HX
    Registered Users Posts: 1,705 ✭✭✭50HX


    patsy_mccabe wrote: »
    Feck it anyway. Only last week cutting a hedge on the farm and a relative said to me that it was Japanese Knotweed. Never knew I had it.


    it'll be up again just watch out for it other spots as when it's cut it has a tendancy to sprout elsewhere

    think toots can be connected underground up to 5 meters

    they recommend no cutting burning or digging

    all we've left is to spray em....cursed bucking stuff

    what did you cut the hedge with??


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    #21
    GhostyMcGhost
    Registered Users Posts: 1,349 ✭✭✭GhostyMcGhost


    dryan wrote: »
    http://www.breakingnews.ie/ireland/residents-fear-for-homes-over-japanese-knotweed-infestation-794801.html

    Started of with a small infestation 2 years ago in a beech hedge at the road entrance to the home place.
    Was out trimming the hedge earlier in the week and i see thats its spreading at an alarming rate along the hedge on the site boundary.

    Also starting to notice it in the farm boundary fences as well.

    Is there any product out there that will kill it?

    The article is annoying. No money to fix the problem? They'll pay more in the long run going to court and having to end up repairing up to 3 homes

    It's not the knotweed that needs eradicating...


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    #22
    patsy_mccabe
    Registered Users Posts: 10,707 ✭✭✭✭patsy_mccabe


    50HX wrote: »

    what did you cut the hedge with??
    No I didn't cut any of the Japanese knotweed. Relative warned me not to.

    'When I was a boy we were serfs, slave minded. Anyone who came along and lifted us out of that belittling, I looked on them as Gods.' - Dan Breen



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    #23
    dodod
    Registered Users Posts: 31 ✭dodod


    +1 for icade found it very good


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    #24
    cosbawn
    Registered Users Posts: 120 ✭✭cosbawn


    There is a substantial crop of JK on neighbouring property. Small country lane divides us. Some small shoots are right at the edge of the road. I’m sick at the thoughts of it coming in. So much so that I’m gonna spray it in the autumn. But In the mean time would it be worth my while spraying those young smaller shoots to stop them getting too tall. No water course nearby no animals grazing


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    #25
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    cosbawn wrote: »
    There is a substantial crop of JK on neighbouring property. Small country lane divides us. Some small shoots are right at the edge of the road. I’m sick at the thoughts of it coming in. So much so that I’m gonna spray it in the autumn. But In the mean time would it be worth my while spraying those young smaller shoots to stop them getting too tall. No water course nearby no animals grazing

    Call the local County Council first. If they're no help then a dose of Roundup won't hurt. But do NOT cut, strum or anything like that.


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    #26
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    cosbawn wrote: »
    There is a substantial crop of JK on neighbouring property. Small country lane divides us. Some small shoots are right at the edge of the road. I’m sick at the thoughts of it coming in. So much so that I’m gonna spray it in the autumn. But In the mean time would it be worth my while spraying those young smaller shoots to stop them getting too tall. No water course nearby no animals grazing

    Yep thats standard practice. One dose end of May to keep them from getting too big then another end of August beginning of September or later depending where you are.


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    #27
    cosbawn
    Registered Users Posts: 120 ✭✭cosbawn


    TomOnBoard wrote: »
    Call the local County Council first. If they're no help then a dose of Roundup won't hurt. But do NOT cut, strum or anything like that.

    There are numerous notices about put up by the council to stop hedge cutting. That seems to be the height of it ! Maybe they gonna spray in the autumn. No I won’t cut or anything like that. Give a good spray tomorrow. Thanks


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    #28
    49801
    Registered Users Posts: 1,844 ✭✭✭49801


    My under standing is roundup will kill it if if sprayed on leaves but takes several years longer with more applications. Injecting helps kill plant quicker but harder to do. Timing important as previously mentioned


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    #29
    orm0nd
    Registered Users Posts: 4,180 ✭✭✭orm0nd


    Roundup Bioactive or Garlon Pro


    Spray early August and repeat mid September doing any missed sprouts and re growth

    Spraying in May. While it might look good originally is actually doing more harm than good long-term cos the chemical is not getting far enough into the root system

    Clearance takes 3 to 7 years

    It spreads on soil do not cut on road sides is for fear of even tidy amounts of clay being transported with the flail hedge cutters

    It can remain dormant for decades and suddenly burst into life if soil is disturbed

    Not spread by seeds or stems if soil free


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    #30
    yosemitesam1
    Registered Users Posts: 2,948 ✭✭✭yosemitesam1


    cosbawn wrote: »
    There are numerous notices about put up by the council to stop hedge cutting. That seems to be the height of it ! Maybe they gonna spray in the autumn. No I won’t cut or anything like that. Give a good spray tomorrow. Thanks
    Spraying this early will cause some of the root system to go dormant and it will reappear over a long period


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    #31
    blue5000
    Moderators, Society & Culture Moderators Posts: 12,630 Mod ✭✭✭✭blue5000


    My advice is wait until a warm, sunny day in mid-august to spray the whole plant with roundup+a sticker. If you miss any of it spray it again about 2-3 weeks later. I had some in a hedge and killed it this way.

    If the seat's wet, sit on yer hat, a cool head is better than a wet ar5e.



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