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Cheshire, United Kingdom Gb

can anyone tell me if there is a weed killer for japanese knot weed or will i have to dig it up.



You poor person !

You can kill Japanese Knotweed ..... eventually.

There is no "silver bullet" , the only way to even make a dent on it is to spray with glyphosate over a LONG period best in the summer or in the autumn when the most nutrients are being taken into the roots and then spraying as soon as it starts to attain any kind of growth.

I would give it a bit of a 1st dose as soon as you see the shoots just to give it a hit before it gets into its stride.

You can also cut the stems down each time you see them appear, but best to use glyphosate as well !
You may have to do this over a number of years , in my professional life I have known of a development site that had a patch of Japanese knotweed that took the best part of 7 years to eradicate !
Best not even attempt to dig it up as you never get all of it up and it can grow from the tinest piece of root or stem. Once it is dug up it is classed as a "controlled waste" under the Environmental Protection Act (Duty of Care) Regulations 1991. Soil containing rhizome material can be regarded as contaminated and, if taken off a site ie your garden, must be disposed of at a suitably licensed landfill site and buried to a depth of at least 5 m. if this is not done you could find yourself charged with an offence under the Wildlife and Countryside Act which can result in a criminal prosecution. An infringement under the Environmental Protection Act can result in enforcement action being taken by the Environment Agency which can result in an unlimited fine. You can also be held liable for costs incurred from the spread of Knotweed into adjacent properties and for the disposal of infested soil.

That wasnt meant to scare you .... just that is the seriousness of this plant !

I would just go at it with the glyphosate !

It is no wonder that there are professional companies that charge a pretty penny to remove this brute from waste ground and developments.

Good Luck !

4 Mar, 2011


I agree with Staffsall - spray just as the leaves start turning yellow, I managed to clear a patch completely in two years.

4 Mar, 2011


Yes, a glyphosphate weedkiller - eg Roundup - is probaly the most practical method for the gardener.

4 Mar, 2011


Im still treating mine with Roundup but it still persists after two years. Has anyone tried bleach - I have been told this works!!

4 Mar, 2011


id cut as much down as possible and use weed supressent everyweay if you want a quicker fix .

4 Mar, 2011


its a shame ive seen an adult one of these (weeds)
and they looked realy stunnimg honestly . i get the fealing bamboo will cause some trouble in the future . especialy between neighbers lol .

4 Mar, 2011


Yes it is a shame that such a thuggish plant is actually quite pretty. I am told that it is an important late season nectar plant for insects .

4 Mar, 2011


its lovley allowed to grow to its full size . quite huge leaves and very orientle . excuse my spelling lol .

4 Mar, 2011


Our council produces a leaflet on Japanese Knotweed control. The online version is here -

You may need to zoom in to read it easily.

4 Mar, 2011


cool thanx beattie x .

4 Mar, 2011


I agree with staffsal. We had it coming through our lawn about 5yrs ago, we sprayed it with glyphosate every time we saw shoots coming up. We noticed it growing behind a shrub at the back of the border and blasted it, we could also feel the roots under the surface of the lawn. It only took us over the summer to get rid of it. It left the lawn in a poor state at first, patchy and yellow. It took a couple of years to recover but was worth it in the end.....Good luck !

4 Mar, 2011


i didnt quite do the same lemondrop and mine wasnt in my lawn and i got ground elder which proved much harder to the point of me not having a lawn lol . the not weed thow as it had only just started . i just kept looking and ripping up any bits i sore growing and eventualy it couldnt keep up with me but thats only if its very light .

8 Mar, 2011

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