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Japanese knotweed?

Hi all,
My husband and I have just started renovating an old house with a very over grown garden, full of brambles and weeds up to the waist. We cleared it all and managed to get some turf down, but while we were digging it all up, there was one plant starting to grow which looked woody and hollow, almost like a peony does before it starts sprouting back up in spring. There were lots of actual peonies in the garden where there must have been flowerbeds a long time ago, so we saved it just in case. Unfortunately however, it is definitely not a peony!!As a few weeks have gone by, it’s shot up very quickly and now that I can see it’s stems, I’m thinking it might be the dreaded knotweed! Please could anyone confirm from the photographs? Your help is greatly appreciated! 


  • BorderlineBorderline Posts: 4,688
    I agree with you, it is Japanese Knotweed. Let's see if others agree.
  • punkdocpunkdoc Posts: 13,242
    I'm afraid I think it is.
    There are ashtrays of emulsion,
    for the fag ends of the aristocracy.

    S.Yorkshire/Derbyshire border
  • Oh dear, I was hoping someone would tell me it was something else! Never mind, into battle I go! Thanks for your help  :)
  • DovefromaboveDovefromabove Posts: 82,740
    punkdoc said:
    I'm afraid I think it is.
    I think so too ... sorry. 
    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • LG_LG_ Posts: 4,063
    Yes, it is.
    'If you have a garden and a library, you have everything you need.'
    - Cicero
  • GemmaJFGemmaJF Posts: 2,286
    Be aware of all the regulations regarding disposal (brought in to prevent it spreading into the wild). It is a real pain.

  • GemmaJF said:
    Be aware of all the regulations regarding disposal (brought in to prevent it spreading into the wild). It is a real pain.

    Yes it’s a pest! We will get a company to come over and give us a quote to get rid. Luckily there’s only about 5 stems of it so it’s not too large an area, but it’s not worth messing with and taking the risk!
  • TopbirdTopbird Posts: 7,707
    Hi @siobhan_jns

    If it’s only a small area I would dig up any surrounding plants (keep them in pots or find them another temporary home elsewhere in the garden) and then start regular applications of a glyphosate based weedkiller.

    You sound like a sensible non-panicky person so you’ll know to apply to the leaves when the plant is growing away strongly. No point cutting it down and spraying the ground. Reapply as new leaves and growth appear. With a bit of luck several applications will kill it unless it’s spreading onto your land from somewhere else....

    Our local tree surgeon reckons he cleared a large area in their storage yard of the stuff using glyphosate.

    You should be able to buy glyphosate from the internet if you don’t have any to hand. It’s cheaper to buy the concentrate and dilute it yourself

    When the lock down is ended you can call in a specialist company if you need to - hopefully you won’t.🙂
    Heaven is ... sitting in the garden with a G&T and a cat while watching the sun go down
  • Hi @Topbird

    Thanks for the advice, I might do that then before calling anyone out, they wouldn’t be able to come out for a few weeks anyway with the current situation, so at least by spraying it I would hopefully stop it from getting any worse. If it goes into my new turf I will be put out! 
  • SmudgeriiSmudgerii Posts: 185
    I would recommend buying some ammonium sulphamate from ebay, probably 5kg, it is sold as a compost accelerator.

    Mix some with wallpaper paste powder to make a thick paste for painting on the leaves and stems, then cover with clear plastic bags.  At the same time mix some with warm water to dissolve the crystals 1kg to 1 litre, and now the awkward part....  you need to inject the bottom of the stems with this solution ( how you get the necessary equipment is for you to decide, but it is readily available ).  Keep this up every other day for as long as you see growth.
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