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Japanese Knotweed - how to kill?

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    #32
    orm0nd
    Registered Users Posts: 4,177 ✭✭✭orm0nd


    I have some pics stored somewhere on cloud (but can't find them now) of a massive "crop" we are trying to eliminate

    it was over 4 mtrs high and approx 40 mtrs X 30 mtrs in size we are working our way inwards about 3 to 4 mtrs each year

    most important points

    Timing: of application and as many leaves as possible getting thorough wetting

    Chemical: (Roundup BIOACTIVE or Garlon Pro,)

    mixing: 200 ml chemical to 10 ltrs water, ( no more no less)

    weather conditions at time of spraying


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    #33
    Markcheese
    Registered Users Posts: 8,430 ✭✭✭Markcheese


    If you can get some red and white warning tape put a boundary around the stuff on the roadside and also a sign with roundup do not cut...and spray mid to end summer....
    Not a whole pile else you can do... As its not your land...

    Slava ukraini 🇺🇦



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    #34
    forgottenhills
    Registered Users Posts: 441 ✭✭forgottenhills


    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

    If the JK on our neighbours property is close to their house then you could let them know that their property value will be severely reduced by the presence of JK and that if it gets close to their house it will undermine the house's foundations. That might get their attention.

    As far as I know you now have to declare that your property is JK free when selling a property in the UK.


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    #35
    cosbawn
    Registered Users Posts: 120 ✭✭cosbawn


    Thanks so much for all the advice everyone. There is no house on neighbouring property and the land is totally unkempt. Is that the word to use? It’s just wild. You couldn’t walk into the fields without at least a pair jeans you’d be ripped to pieces from briars. I’ve never seen anything like it I never see anyone around. But if I do I’ll mention it. I don’t mind doing it. It’s in my own best interest. I’ll wait till August and then do a second spray few weeks later. Fingers crossed in the mean time 🀞🀞


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    #36
    patsy_mccabe
    Registered Users Posts: 10,698 ✭✭✭✭patsy_mccabe


    patsy_mccabe wrote: »
    Is this it?

    Just checked the knotweed I sprayed last year and all dead as a door nail. Then 20 feet or so away spotted a new Bush. Jeez, could be an ongoing battle.

    '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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    #37
    professore
    Closed Accounts Posts: 5,857 ✭✭✭professore


    It might finally push the govt to tax the hell out of land left sitting idle.


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    #38
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    patsy_mccabe wrote: »
    Just checked the knotweed I sprayed last year and all dead as a door nail. Then 20 feet or so away spotted a new Bush. Jeez, could be an ongoing battle.

    What I think happens and I've seen the same thing happen time and time again is that you can get a good kill on the main plant but the root system is so extensive that the furthest most bits of root from the main plant are still alive.

    The following year these roots now disconnected from the dead main plant produce buds of their own and you get new plants.

    It may be a battle but the new plants shouldn't have anything like as much strength as the original established plants so are easier to kill.


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    #39
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    professore wrote: »
    It might finally push the govt to tax the hell out of land left sitting idle.

    A bit harsh, unless its building land that's being hoarded as such. A smallholding of briars and rushes may well be someones retirement home or simply his expression of nature at its most beautiful.

    That said, any land containing unmanaged noxious weeds are subject to legal oversight and possible action. This used to be fairly rigorously policed in times past in respect of ragwort. Perhaps JK should be similarly managed, if its not already.


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    #40
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    cosbawn wrote: »
    Thanks so much for all the advice everyone. There is no house on neighbouring property and the land is totally unkempt. Is that the word to use? It’s just wild. You couldn’t walk into the fields without at least a pair jeans you’d be ripped to pieces from briars. I’ve never seen anything like it I never see anyone around. But if I do I’ll mention it. I don’t mind doing it. It’s in my own best interest. I’ll wait till August and then do a second spray few weeks later. Fingers crossed in the mean time ����

    If you can get into it now then there is no reason not to spray it.

    You are a little late as the point of an early spray in May is to reduce the height of the weed so its easy to get the important dose of glyphosate on it in September. Its no point waiting till August or September and then having a crop so large you can't get anywhere near it with a spay lance.

    If you have the time in late August then two sprays with two weeks gap increase the kill rate.


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    #41
    cosbawn
    Registered Users Posts: 120 ✭✭cosbawn


    my3cents wrote: »
    If you can get into it now then there is no reason not to spray it.

    You are a little late as the point of an early spray in May is to reduce the height of the weed so its easy to get the important dose of glyphosate on it in September. Its no point waiting till August or September and then having a crop so large you can't get anywhere near it with a spay lance.

    If you have the time in late August then two sprays with two weeks gap increase the kill rate.

    Yes it’s already fairly high. But I had planned to use a high step ladder from the road side at least to try and reach in. I know that I may not be able to get right into the middle of it this year as ground is very rough lots of large rocks & no point getting injured. It will be a work in progress. I have Grazon Pro which replaced Grazon 90. I’ll let ye know how I get on hopefully it won’t be too windy


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    #42
    Bass Reeves
    Registered Users Posts: 18,188 ✭✭✭✭Bass Reeves


    Monsanto have bought out Roundup capsules/bullets for killing the roots of trees. You drill a hole and plant them in the trunk of the tree. These are slow and long acting. Would these be any use in the fight against knotweed

    Slava Ukrainii



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    #43
    orm0nd
    Registered Users Posts: 4,177 ✭✭✭orm0nd


    Bass Reeves wrote: »
    Monsanto have bought out Roundup capsules/bullets for killing the roots of trees. You drill a hole and plant them in the trunk of the tree. These are slow and long acting. Would these be any use in the fight against knotweed

    No


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    #44
    cosbawn
    Registered Users Posts: 120 ✭✭cosbawn


    Well it’s done. But no where near as good as I’d hoped. I couldn’t get near the JK in places due to the briars. So I sprayed them and will continue to do so over the summer and try and kill them off. SBK be ok for this?
    “Brushwood Weed Killer - Directions for Use
    Woody weeds: Apply from May to October”
    How often should I use do ye think?

    I’ll hold on to Grazon for “good use”. Not to cheap that stuff.
    Well all beginners are weak and sure if it was easy we’d have no need for Boards !!


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    #45
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    cosbawn wrote: »
    Well it’s done. But no where near as good as I’d hoped. I couldn’t get near the JK in places due to the briars. So I sprayed them and will continue to do so over the summer and try and kill them off. SBK be ok for this?
    “Brushwood Weed Killer - Directions for Use
    Woody weeds: Apply from May to October”
    How often should I use do ye think?

    I’ll hold on to Grazon for “good use”. Not to cheap that stuff.
    Well all beginners are weak and sure if it was easy we’d have no need for Boards !!

    Roundup or other glyphosate based weed killer will do a fairly good job on briars and tbh because it cheaper than many of hormone weedkillers (like SBK and Grazon) on uncropped land its the obvious choice.

    The problem is that you will end up with just bare soil when you use glyphosate, the hormone weedkillers leave the grass.


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    #46
    orm0nd
    Registered Users Posts: 4,177 ✭✭✭orm0nd


    professore wrote: »
    It might finally push the govt to tax the hell out of land left sitting idle.
    my3cents wrote: »
    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.
    my3cents wrote: »
    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.
    my3cents wrote: »
    What I think happens and I've seen the same thing happen time and time again is that you can get a good kill on the main plant but the root system is so extensive that the furthest most bits of root from the main plant are still alive.

    The following year these roots now disconnected from the dead main plant produce buds of their own and you get new plants.

    It may be a battle but the new plants shouldn't have anything like as much strength as the original established plants so are easier to kill.


    your problem is that you are using the incorrect approach

    you are spraying far too early in the season and even worse giving out wrong advise on here to get more people in the same situation as yourself

    this not a personal attack on you, I value your posts on other forums but you are out of your league here please do not continue to post misleading information

    for any body in the north tipp area or passing through , Dow & Arrabawn co-op held an excellent information morning in Garrykennedy last year, there is a large growth at the rear of Larkin's pub,

    it was late in the year & I don't know if it was sprayed or not but would be interesting to see the results

    also a big mistake a lot of the cc's are making is not checking inside the roadside hedges


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    #47
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    orm0nd wrote: »
    your problem is that you are using the incorrect approach

    you are spraying far too early in the season and even worse giving out wrong advise on here to get more people in the same situation as yourself

    this not a personal attack on you, I value your posts on other forums but you are out of your league here please do not continue to post misleading information

    for any body in the north tipp area or passing through , Dow & Arrabawn co-op held an excellent information morning in Garrykennedy last year, there is a large growth at the rear of Larkin's pub,

    it was late in the year & I don't know if it was sprayed or not but would be interesting to see the results

    also a big mistake a lot of the cc's are making is not checking inside the roadside hedges

    Ok so a professional gardener who has been dealing with Japanese Knotweed for the last 35 years is out of their depth and someone who goes to an information morning is an expert?

    How many sites with Knotweed have you treated and how many have you eradicated it from?

    I will state again spraying early in the year mid May being ideal so we are getting too late for that is good practice because it reduces the height of the crop when it comes to the main spray timing at the end of the growing season.

    You are advising people to fail in their task by allowing the weed to get too big. How do you advise spraying a weed that is 3m high and so dense that you can't even fight your way into without a machete?


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    #48
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    So here is Monsanto's recommendation where specialist spray equipment isn't available - Hmmm I wonder what they make?

    https://www.alci.ie/fs/doc/Round%20Up%20-%20Japanese%20Knotweed%2014-05-10.pdf
    2) TWO FOLIAR SPRAYS AT 1 METRE STEM HEIGHT
    Spray the plants at 1-1.5m tall, in late May, with a rate of 5.0 l/ha and repeat on any regrowth
    later in the season once they reach 1.5m again. This technique can be used where
    stands are particularly thick, as part of an integrated control programme or where long lances
    are not available.

    I modify that slightly and leave the second spray until the end of the season rather than just spraying the regrowth as it occurs. I have no argument that the later spray is the most effective because I have seen the results myself loads of times.


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    #49
    blue5000
    Moderators, Society & Culture Moderators Posts: 12,627 Mod ✭✭✭✭blue5000


    Let's all take a step back folks, and calm down a bit.

    In a severe infestation it may take several years to eradicate it. If possible wait till August when the plant translocates the herbicide down to the roots.

    Monsanto advice;

    Treatment in early season is usually less effective because the plant is naturally pushing
    nutrients strongly upwards to the developing canes. This can lead to a good initial top kill
    of leaves but less transport to the rhizomes. Regrowth after early season treatment can
    often be ‘epinastic’ ie stunted and distorted and because it is not actively growing it is
    more difficult to kill    .

    Full leaflet here.

    https://www.alci.ie/fs/doc/Round%20Up%20-%20Japanese%20Knotweed%2014-05-10.pdf

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



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    #50
    Mousewar
    Registered Users Posts: 2,741 ✭✭✭Mousewar


    So looks we have this in our estate here in Dublin. It's about 8ft tall already in a garden across from me and is now running along the wall on the common green area where it is about 5ft. There's a few other patches on it here and there as you go along.
    I have two questions.
    First, is there anything in particular I can do to ensure it doesn't come onto my property? My garden is about 7 or 8 metres from it.
    Second, we have informed the council who say they'll be out. This would be dun laoghaire rathdown. Does anyone have experience with the council treating this? Basically I'm wondering can I trust them to do it properly or should I be thinking of taking matters into my own hands?


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    #51
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    Leave it to the Council IMO


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    #52
    my3cents
    Closed Accounts Posts: 9,764 ✭✭✭my3cents


    Mousewar wrote: »
    So looks we have this in our estate here in Dublin. It's about 8ft tall already in a garden across from me and is now running along the wall on the common green area where it is about 5ft. There's a few other patches on it here and there as you go along.
    I have two questions.
    First, is there anything in particular I can do to ensure it doesn't come onto my property? My garden is about 7 or 8 metres from it.
    Second, we have informed the council who say they'll be out. This would be dun laoghaire rathdown. Does anyone have experience with the council treating this? Basically I'm wondering can I trust them to do it properly or should I be thinking of taking matters into my own hands?

    I'd get back to the council and ask them what their action plan is for treating JK. I suspect they are just doing one kill at the end of the season which is ideal however you are left wondering if they are going to remember for the next 3 months.

    The chances are if they don't forget you (they shouldn't) then they will do a decent enough job a lot of councils are now using newer chemicals like Icade which from what I have seen do an excellent job. As I keep on being pulled up for saying while spraying late works best the crop can be so large that some areas get missed so one way or another you'll get regrowth next year unless you are very lucky. But with you monitoring it and getting on to the council and repeatedly reporting any regrowth over the next few years it should be eradicated.

    The problem may be that the Council won't spray the garden in front of you if that is private property another reason to check with them on their policy for dealing with JK. If the council won't do that area then plenty of advice here already on what you can do.

    I've done some small areas with Roundup in a 1litre spray bottle with good results (its easy to hide and I didn't want to wander around the beach with a big yellow 20litre Knapsack sprayer) so I know its not like you have to go buying a lot of expensive equipment to deal with it. A quick note about it growing on the beach, the bastard stuffs roots wash down rivers go out to sea and root again when they get washed up on the top of the beach - it really is tough stuff.


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    #53
    Mousewar
    Registered Users Posts: 2,741 ✭✭✭Mousewar


    my3cents wrote: »
    I'd get back to the council and ask them what their action plan is for treating JK.
    Yeah I did ask when I called but you're just talking to some guy on a desk who doesn't know that stuff. He just said the lads who come out will know what they're doing.

    my3cents wrote: »
    The problem may be that the Council won't spray the garden in front of you if that is private property another reason to check with them on their policy for dealing with JK. If the council won't do that area then plenty of advice here already on what you can do.

    Yeah that is my worry although it's clearly the same plant, just two sides on the wall. That house is rented and I get the impression they guy living there doesn't give a damn. I'll try to get onto the landlord.

    Thanks for the advice.


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    #54
    Good loser
    Registered Users Posts: 3,181 ✭✭✭Good loser


    A smallish clump I sprayed with Grazon last year came again this year and last week I decided to pull it manually, which was surprisingly easy to do. All came up except one, the biggest clump, which I just broke down.
    Underground there is a mass of peat like material - small or large depending on the mass overground. The outlying plants were singletons but centre ones had 4 to stalks.
    Will go back with Grazon later in year.


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    #55
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    Good loser wrote: »
    A smallish clump I sprayed with Grazon last year came again this year and last week I decided to pull it manually, which was surprisingly easy to do. All came up except one, the biggest clump, which I just broke down.
    Underground there is a mass of peat like material - small or large depending on the mass overground. The outlying plants were singletons but centre ones had 4 to stalks.
    Will go back with Grazon later in year.
    Totally in contravention of current best practice advice. Even tiny fragments can reproduce. Where did you put the pieces you 'broke down' and pulled out?


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    #56
    Mousewar
    Registered Users Posts: 2,741 ✭✭✭Mousewar


    I noticed today that someone, a neighbor perhaps, pulled one of the stalks away, presumably it was starting to obstruct the pathway. I can't see any of it left in the ground. Will that one grow back this year or will it re-emerge next year. I'd prefer this summer so it can get sprayed with the rest.


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    #57
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    Mousewar wrote: »
    I noticed today that someone, a neighbor perhaps, pulled one of the stalks away, presumably it was starting to obstruct the pathway. I can't see any of it left in the ground. Will that one grow back this year or will it re-emerge next year. I'd prefer this summer so it can get sprayed with the rest.

    Id be more concerned about where he put the bits he pulled away! A recipe for another infestation! When will we run adverts on bloody TV to tell ppl to not pull the stuff???


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    #58
    orm0nd
    Registered Users Posts: 4,177 ✭✭✭orm0nd


    my3cents wrote: »
    Ok so a professional gardener who has been dealing with Japanese Knotweed for the last 35 years is out of their depth and someone who goes to an information morning is an expert?

    How many sites with Knotweed have you treated and how many have you eradicated it from?

    I will state again spraying early in the year mid May being ideal so we are getting too late for that is good practice because it reduces the height of the crop when it comes to the main spray timing at the end of the growing season.

    You are advising people to fail in their task by allowing the weed to get too big. How do you advise spraying a weed that is 3m high and so dense that you can't even fight your way into without a machete?

    I am a qualified sprayer operator, fully registered and certificates to prove it.

    I have been in discussion with 2 CC , and have attended courses organized by the 2 main companies supplying the chemical recommended .

    you will never ever get a total kill spraying in may , end of discussion

    I'm only 2 years attacking this menace and like you got very poor results first year because I didn't know the correct procedure ,

    I havent inspected last year's sites closely yet but from a distance looks promising

    Anyhow no more posts from me here ,

    I may post pics later ( good or bad results I ll post them, but I wont be going near sites the until august)


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    #59
    orm0nd
    Registered Users Posts: 4,177 ✭✭✭orm0nd


    Good loser wrote: »
    A smallish clump I sprayed with Grazon last year came again this year and last week I decided to pull it manually, which was surprisingly easy to do. All came up except one, the biggest clump, which I just broke down.
    Underground there is a mass of peat like material - small or large depending on the mass overground. The outlying plants were singletons but centre ones had 4 to stalks.
    Will go back with Grazon later in year.

    and next year and the year after


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    #60
    death1234567
    Registered Users Posts: 3,331 ✭✭✭death1234567


    Good loser wrote: »
    A smallish clump I sprayed with Grazon last year came again this year and last week I decided to pull it manually, which was surprisingly easy to do.
    And also spectacularly stupid. Enjoy its inevitable return.


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    #61
    TomOnBoard
    Registered Users Posts: 5,109 ✭✭✭TomOnBoard


    death1234567 wrote: »
    And also spectacularly stupid. Enjoy its inevitable return.

    And get ready for another infestation wherever the pulled pieces were dumped!!!


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