Japanese Knotweed :(

[Mochamoo]

What's the best method for dealing with it?

I've heard several different suggestions some range form 6 months to 4 years! Has anyone quickly and effectively got rid of this evil weed?

[TEB]

Not much works against, there is talk that the powers that'll be are trialling a bug that attacks it, manual clearance seems to be the only sure fire method.

[Mochamoo]

I was really hoping for a miracle cure I have a patch about 3 metres by 4 metres and I just know its going to break my back clearing it!

[zazen999]

If there was a miracle cure, it probably wouldn't be a problem.

Don't you have to take special measures to dispose of it?

[TEB]

I was really hoping for a miracle cure I have a patch about 3 metres by 4 metres and I just know its going to break my back clearing it!

Nope no miracle cure, it's roots can go 7m horizontally and 5m down, it can lay dormant for years and its estimated that it will cost Britain £2.6 billion to clear it. Lets hope that the insect called aphalara itadori passes all the tests and gets to work, in the last 5 years I have seen it invade vast swathes of the nearby river - its horrible.

[TEB]

Do not compost cuttings or put them in the rubbish bin. It is an offence under the Wildlife and Countryside Act to cause Japanese knotweed to grow in the wild so if you dispose of it carelessly you will be breaking the law. Do not dump it in the garden waste bin of your local recycling centre. Japanese knotweed (and contaminated soil) is classed as "controlled waste", which means you must only dispose of it at certain, licensed landfill sites: check with your local council. If you are allowed to have a fire, burning the waste on site is another way to dispose of it. There are also commercial companies that specialise in the eradication of Japanese knotweed.

[bluemoon]

My daughter's father in law eventually dug his garden out to the bedrock, disposed of the soil, bought in tons of fresh topsoil, then used an industrial strength weedkiller on that, just in case. It worked for two years, until the ones that had found their way under the fence to the neighbours made their way back. Nightmare stuff.

[Stew]

You should contact your local authority, who will I am sure advise.

[Mochamoo]

I think I will burn it Nothing like a good bonfire and marshmallows to make you feel better about all that digging. Its partially invaded the compost so do I have to dispose of that as well?

[TEB]

Yes to the compost and the Wildlife and Countryside Act will apply as the soil is contaminated

[WiseCharlieD]

You're wasting your time burning it! You will have to dig down 5m as TEB said and even then it can still get back onto your land as it will lie dormant for 20 years.

You really need to bring in a specialist to use a proper spray or inject it which will kill it all the way down to the roots. Even then it still needs resprayed another 3 times at least in the first year anda gain in the second. After that it should be inspected every year.

If you get rid of it on your property and a neighbour has it too make sure they also kill it as it will easily grow back onto your land afterwards.

[Nicos]

Apparently it is possible to do this yourself!

I received this information from the head of an Invasive Species charity...

QUOTE -"Glyphosate can take up to three years of control to eradicate JK. It doesnt matter what concentration you apply it - the plant will only absorb a maximum amount and anything extra wont be taken up, so there is no point in applying any more than is recommended for each brand of pesticide.

The best time to spray the plant is towards the end of the summer when the plant is in flower - and not before. Many people make the mistake of spraying it now, again mid summer and then by the end of the summer when it is drawing all the energy from the leaves back into the root system (which is when you want to hit it) and there are no leaves to spray to take up the pesticide!

So, I recommend spraying it when it is flowering (around August time) with glyphosate. Make sure that its the leaves that are sprayed - not the stem.
It works best if the plant hasnt been 'bodge sprayed' before- as it might now have pigmy leaves and stronger. It needs to be repeated next year if it comes back and then again until it goes away.
It depends how large the stand is...but the root system can be 3m down and 7m across so make sure they have looked around the obvious plants they can see as every bit needs to be sprayed. "

No need to pay vast amounts if you can manage it yourself!
Certainly worth a bash!

[bearded bloke]

Further to what Nicos posted ^^ the very best time to spray Glyphosates is at dew point & preferably evening dew point as it is less likely to turn into a surface "salt" due to evaporation.
Dew point is when the plant naturally "drinks" & so will take the product down more readily,there is also the lateral advantage that while dew is forming the air is "heavier" so in consequence the risk of wind borne "over spray" is greatly reduced