Anybody else here struggling with Japanese Knotweed?

Niall_daaS

my3cents wrote: »

but the problem is you then have the cut stems to deal with and you can't take them to the tip or compost them.

I've read some source that say burning would be the only propper way to handle remainders responsible.

my3cents

Niall_daaS wrote: »

I've read some source that say burning would be the only propper way to handle remainders responsible.

The problem in Ireland is getting permission to burn, not an issue in the UK. Most of the source material is from the UK and even Irish sources often refer to DEFRA documents.

yellowlabrador

a walk way near the river here in Dunmanway has been closed off for 5 years. Co cork has hired a man to get rid of the knot weed. It's really bad and it's got worse over the past year. It's over 6 foot tall in places and walking down the path was like entering a tunnel. apparently the path will be close for 5 years. I'll miss it because I loved going there with the dog.

sheesh

my3cents wrote: »

Thats true but the problem is you then have the cut stems to deal with and you can't take them to the tip or compost them. Better in a lot of cases to spray or inject what you see and only cut down dead stems.

As I mentioned before it often goes dormant for a year while it shakes off the effects of the glyphosate and then comes back two years later.

you don't have to cut it off completely just slice- bend over but for a big lot I suppose just spray and spray again when they come back up.

I'm after the first spray last year and keeping an eye it at the moment

recedite

Niall_daaS wrote: »

I was walking in Wicklow recently and I might have been stumbled over jap. knotweed. Was basically an abandoned and derelict house next to an old forest path in the middle of a new spruce plantation...

I wouldn't worry too much about it. It cannot compete against spruce woods, or live in an exposed upland situation. These old ruins in the woods are usually in a sheltered spot with a small stream (that was the peoples water supply) so just the ideal spot for JK, but it won't necessarily move from there.
There is a clump of it at a bridge near me, which clump is about 2m wide by 4 or 5m long. Has been there for many years, unchanged. Nobody touches it. Its amazing how quick the stems shoot up in summer, it looks like its going to take over, but then it vanishes again and its back to square one. I think because it's bounded by a tarred road on one side and some trees on the other.
I know its really hard to kill, but I don't think its as invasive as people are making out. It needs a reasonable amount of light and it likes shelter and moisture. So if you could get willow or sally trees established in its place they would probably out-compete it.

yellowlabrador wrote: »

a walk way near the river here in Dunmanway has been closed off for 5 years. Co cork has hired a man to get rid of the knot weed. It's really bad and it's got worse over the past year. It's over 6 foot tall in places and walking down the path was like entering a tunnel. apparently the path will be close for 5 years. I'll miss it because I loved going there with the dog.

Are you sure this isn't Giant hogweed, contact with it can cause skin rashes? It seems unlikely that JK would close off a path, unless nobody was using it.


A local guy who fancies himself as an amateur naturalist/historian was doing a guided walk thing as part of a summer events series last year, and as we all walked past the aforementioned patch of JK, he announced it was Himalayan Balsam and then went on a rant about invasive species.
Thankfully he has never actually tried to hack at it though; all talk and no action.
Anyone who has tried to get rid of a patch of nettles or brambles knows they are hard to kill and that they keep coming back, but yet they don't carpet the entire landscape. So just because a plant is doing well in one spot right now, does not mean its going to take over the entire country by this time next year if its not killed off.

sheesh

tampopo wrote: »

Nobody cares. Report away.

in fairnesss I have noticed al lot of brown patches along the main roads here in kerry where some spraying has obviously been done so someone is out doing something here

Kazbah

Hello all,

I have about 0.5 m2 about 0.75m high of JKW in my back garden. I notice that two bordering gardens are completely overrun with this & bindweed. Am I wasting my time trying to contain my bit if these gardens are not maintained? Also I'd like to pave that area - is that a bad idea in the short term? Any advice?

Thanks

my3cents

Kazbah wrote: »

Hello all,

I have about 0.5 m2 about 0.75m high of JKW in my back garden. I notice that two bordering gardens are completely overrun with this & bindweed. Am I wasting my time trying to contain my bit if these gardens are not maintained? Also I'd like to pave that area - is that a bad idea in the short term? Any advice?

Thanks

Don't do anything yet, and don't cut it down. Wait till the last week of August (later is better but harder to get the timing right) and hit it with as much Glyphosate based weedkiller (like Roundup or one of the cheaper alternatives) as you can. Spray your bit and as much of the bordering gardens as you can get away with. Better still get permission and spay all the knotweed in those gardens as well.

NOTE TO ANYONE WITH JAPANESE KNOTWEED - THE LAST WEEK IN AUGUST AND THE FIRST COUPLE IN SEPTEMBER ARE THE MOST EFFECTIVE TIME TO SPRAY WITH GLYPHOSATE.

Kazbah

Thank you. How long would be safe before paving? I've read here that it takes 3 years to get it under control 😧

monkeynuz

my3cents wrote: »

Don't do anything yet, and don't cut it down. Wait till the last week of August (later is better but harder to get the timing right) and hit it with as much Glyphosate based weedkiller (like Roundup or one of the cheaper alternatives) as you can. Spray your bit and as much of the bordering gardens as you can get away with. Better still get permission and spay all the knotweed in those gardens as well.

NOTE TO ANYONE WITH JAPANESE KNOTWEED - THE LAST WEEK IN AUGUST AND THE FIRST COUPLE IN SEPTEMBER ARE THE MOST EFFECTIVE TIME TO SPRAY WITH GLYPHOSATE.

Absolute rubbish, I've said on here numerous times, the sooner you start the better, July onwards is perfect. Leave it too long and the plant isn't actively growing and won't take the chemical down.

And stem injection is the most effective way of killing it combined with spraying top and underside of leaves.

Why do you insist on giving duff advice?

recedite

I'd agree that now is a good time to spray, while plants are still actively growing. It will start raining again some time in September, and any spray will be useless then.

my3cents

monkeynuz wrote: »

Absolute rubbish, I've said on here numerous times, the sooner you start the better, July onwards is perfect. Leave it too long and the plant isn't actively growing and won't take the chemical down.

And stem injection is the most effective way of killing it combined with spraying top and underside of leaves.

Why do you insist on giving duff advice?

If you bother to read the reports and fact sheets online about Japanese Knotweed then you'll find that other people with first hand experience have found September the best month for spaying for maximum effect.

One example would be from the Invasive Species Ireland website http://invasivespeciesireland.com/toolkit/invasive-plant-management/terrestrial-plants/japanese-knotweed/ where they state Mid to Late September being the ideal time for spaying glyposate. However my own experience from controlling the Japanese knotweed on my own land, adjoining farm land, neighbors gardens and some amenity areas the council never bother with is that the weather isn't always ideal that late so I plan the main spray of the year from the last week of August. The land around here is also exposed to the sea and I find the Japanese knotweed here has lost many of its leaves by the last week in September so I time my main attack a week earlier.

It doesn't mean I don't spray earlier in the year because I do but I still follow up with a later spray from the end of August. Earlier spaying is for two reasons one is to get the growth to a height so you can get into it for a late spray and the other is to follow up on small areas of regrowth. I have two areas to be sprayed in the next couple of weeks. Both were sprayed twice earlier in the year but all I was spraying was tiny bits of fasciated (deformed) growth because I had the maximum impact from a late spraying last year. Previously you couldn't walk across either site it was so dense with knotweed.

I've injected small isolated clumps and it gives great results but its not practical for me to do that on larger areas.

monkeynuz

my3cents wrote: »

If you bother to read the reports and fact sheets online about Japanese Knotweed then you'll find that other people with first hand experience have found September the best month for spaying for maximum effect.

One example would be from the Invasive Species Ireland website http://invasivespeciesireland.com/toolkit/invasive-plant-management/terrestrial-plants/japanese-knotweed/ where they state Mid to Late September being the ideal time for spaying glyposate. However my own experience from controlling the Japanese knotweed on my own land, adjoining farm land, neighbors gardens and some amenity areas the council never bother with is that the weather isn't always ideal that late so I plan the main spray of the year from the last week of August. The land around here is also exposed to the sea and I find the Japanese knotweed here has lost many of its leaves by the last week in September so I time my main attack a week earlier.

It doesn't mean I don't spray earlier in the year because I do but I still follow up with a later spray from the end of August. Earlier spaying is for two reasons one is to get the growth to a height so you can get into it for a late spray and the other is to follow up on small areas of regrowth. I have two areas to be sprayed in the next couple of weeks. Both were sprayed twice earlier in the year but all I was spraying was tiny bits of fasciated (deformed) growth because I had the maximum impact from a late spraying last year. Previously you couldn't walk across either site it was so dense with knotweed.

I've injected small isolated clumps and it gives great results but its not practical for me to do that on larger areas.

Just because they say it doesn't mean they're right, I have had success on a commercial basis of eradicating knotweed the correct way, but if people don't want to follow the correct method that's up to them.

my3cents

I forgot to include the reasoning for the late spraying. The theory is that as the plant naturally moves food reserves from the stems and leaves back into the roots ready for winter it pulls down the glyphosate with it which has all winter to act on the plant.

my3cents

monkeynuz wrote: »

Just because they say it doesn't mean they're right, I have had success on a commercial basis of eradicating knotweed the correct way, but if people don't want to follow the correct method that's up to them.

From a UK (NI) government website http://www.doeni.gov.uk/niea/japanese_knotweed-commonly_asked_questions__2_.pdf

Japanese knotweed can also be controlled by using an approved
systemic herbicide over several years, such as glyphosate, by a
competent fully trained individual. The herbicide should be applied
to the Japanese knotweed leaves ensuring the maximum surface area
is covered. It is recommended to apply the herbicide during the early
stages of the growing season to knock back the forthcoming seasons
growth. This should be followed up with another herbicide application in
September – October time when the Japanese knotweed is dying back
for the winter, to maximise herbicide uptake into the rhizome system.
This process should be repeated in subsequent years until no regrowth
is observed (4 to 5 years usually). Care should be taken to minimise
herbicide spray onto non-target species. Other herbicides are available
for control. The herbicide selected for control is the decision of the
trained individual. They must ensure it does not breach the herbicide
label conditions. Extra care should be taken when selecting a herbicide
for treating Japanese knotweed near water as not all herbicides are
approved for this use. Consideration should also be taken for public
access.

I'm really not bothered if people want to spray it early and keep at it but my point is you get the biggest effect from glyphosate on Japanese Knotweed when sprayed late in the growing season. Once you have it knocked back its still going to regrow and then with the smaller target areas its open season spray every time you see a leaf of it growing, but if possible time it so you have something to spray late in the season so the chemicals are again taken down into the rhizome.

magicbastarder

from a monsanto brochure:
"As with most broad-leaved perennials, optimum control will be achieved from treatment at flowering in August or September but before die-back."

tampopo

sheesh wrote: »

in fairnesss I have noticed al lot of brown patches along the main roads here in kerry where some spraying has obviously been done so someone is out doing something here

There has been something sprayed on JK in Dublin along the Naas road just past the FBD Insurance building at/near the Kylemore Luas station. The leaves are all brown and withered.

Kazbah

Kazbah wrote: »

How long would be safe before paving? I've read here that it takes 3 years to get it under control 😧

Any opinions?

my3cents

Kazbah wrote: »

Any opinions?

The problem is you are most likely going to have to excavate the ground to put in some form of base for the slabs. When you do that you'll break up the rhizomes and increase the problem, you also have the problem of getting rid of any rhizomes you dig up. If you spray as suggested let the plants die down and can work on top of them and put down a layer of builders plastic you stand some chance as the weakened rhizomes may not have the strength to push back up through it. A neighbour has builders plastic (edit> with a good layer of gravel over it to hold it down) under his decking and its kept the Japanese Knotweed that was there down and its never broken through, the JK in that case had been badly buried by the builder a couple of feet down and came back up all over the rest of the site. Whatever you do keep a hand spray of some glyphosate based product to spray any that pokes up between the slabs.

Eph1958

Hi, anybody got any pics of this JK plague so we can keep a look out for it. Many thanks.

Eph

my3cents

I'll go and take some pics, been meaning to do some of areas that have had different spray treatments and can find some plants to photograph as well.

But a google search has loads of good pictures https://www.google.ie/search?q=japanese+knotweed&tbm=isch&tbo .

Riskymove

Some more info

http://invasivespeciesireland.com/toolkit/invasive-plant-management/terrestrial-plants/japanese-knotweed/

http://www.clarelibrary.ie/eolas/coclare/heritage/pdfs/Japanese_Knotweed.pdf

http://www.doeni.gov.uk/niea/japanese_knotweed-commonly_asked_questions__2_.pdf%E2%80%83

Riskymove

Eph1958 wrote: »

Hi, anybody got any pics of this JK plague so we can keep a look out for it. Many thanks.

Eph

a video on identification:

http://www.fisheriesireland.ie/Invasive-Species/identification-of-japanese-knotweed.html

also:
http://invasivespeciesireland.com/toolkit/invasive-plant-management/terrestrial-plants/japanese-knotweed/identification/


attached is the sheet on how to identify it, very helpful

gman2k

Great! Thanks to this thread I have identified JNW growing just next to my house (within one metre)

yellowlabrador

gman2k wrote: »

Great! Thanks to this thread I have identified JNW growing just next to my house (within one metre)

That isn't japanese knot weed. It's much taller than that.
that one in the picture looks like redshank.

dball

I have roundup XL, is there a recommended ratio of dilution for applying to KW - if i was to spray?

my3cents

dball wrote: »

I have roundup XL, is there a recommended ratio of dilution for applying to KW - if i was to spray?

I use the higher 4l to the hectare rate for any of the products that have 360g per litre equivalent of glyphosate which is most of them including Round Up and Gallop. Its hard to calibrate a knapsack for spraying Japanese knotweed when you are essentially spot weeding so I go with 10ml to one litre.

afaik Roundup XL is a ready to use product that you don't dilute.

Whatever version of gyphosate you use I find with large plants of JK its best to try and wet as much of the plant as possible both top and underside of the leaves.

recedite

The xl in a white container is concentrated at 360g/litre, but there are various versions of roundup in green containers sold in pre-diluted form in garden centres to people with more money than sense.
The instructions for xl say to use a 2% solution if walking with a knapsack sprayer, which is 20ml/litre.
But I use 15ml/ litre for spot spraying. That is based on the instructions on the tiny green bottles of 120g solution which is sold more specifically for hand sprayers. According to those, use 20ml for soft weeds and 40ml for tough briars etc (but that is with the 3x more dilute version at 120g.) So that higher dose of 40ml translates to only 15ml when using the 360g concentrated version. And the lower dose would be 7.5ml.
It gets complicated alright. BTW, you won't be able to buy it without a spraying license after the end of this November.

dball

Thanks for that, this is the one i Have, sorry the pics are so big:

Kazbah

Where can you buy this economical version - just co-ops? I could only see green sprays in B&Q. Should I wear a mask, goggles etc?