Solved Is this Japanese Knotweed?

Discussion in 'Identification Area' started by Woodside1316, Apr 4, 2020.

  1. Woodside1316

    Woodside1316 Apprentice Gardener

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    Concerned these could be Japanese Knotweed but also conscious that they are in 3 distinct locations that previous homeowner maintained very well.

    Also, there has been no spread / invasive behaviour over the past few year.

    In summary I think it looks like an invasive species but behaviour and locations make me think otherwise.

    Any advice would be greatly appreciated!

    Cheers
     

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  2. Silver surfer

    Silver surfer PLANTAHOLIC

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    Welcome to the forums!
    Relax..this is not Japanese knotweed.
    Please add new pics when leaves open.
    Maybe Euphorbia sp.
     
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    • Kristen

      Kristen Under gardener

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      Looks like that to me too (on the one open leaf that I saw, so bit of a small-sample to judge from.
       
    • Woodside1316

      Woodside1316 Apprentice Gardener

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      Thanks all! Panic over, will follow up with some more pictures when leaves open.
       
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      • Woodside1316

        Woodside1316 Apprentice Gardener

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        Would this example with more leaves help more?
         

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      • Cuttings

        Cuttings Gardener

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        The leaf is the wrong shape for J knotweed
         
      • mazambo

        mazambo Total Gardener

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      • Silver surfer

        Silver surfer PLANTAHOLIC

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        Think we need a Euphorbia that suckers.
        Such as the invasive Euphorbia griffithii Fireglow

        Euphorbia griffithii ‘Fireglow’ in spring new young growth | Plant & Flower Stock Photography: GardenPhotos.com

        Euphorbia griffithii Fireglow - Google Search
        ................................................................................................................

        This is Euphorbia lathyris...very distinctive plant.

        euphorbia lathyris - Google Search
         
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        • Woodside1316

          Woodside1316 Apprentice Gardener

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          Updated photo with leaves open.
           

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        • Jack2020

          Jack2020 Apprentice Gardener

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          Hello everyone and wonder if someone can advise. Unlike the lucky poster, Woodside, I have just discovered Japanese Knotweed for real. The shoots are starting to appear in an area approx 1m x 2m in an area of our building plot which we have just cleared. Thankfully we haven’t started any house building but it’s still an unpleasant discovery! I’ve googled and general advice if not causing havoc to buildings is to cut back and treat with Roundup Tree Stump. I’m confused though as it seems I shouldn’t start doing this until late summer. Can anyone advise what I can do meantime.....or can I attack now with the Roundup? Other suggestions are cover with tarpaulin, old heavy carpet to smother....I’d appreciate anyone’s experience.
           
        • Cuttings

          Cuttings Gardener

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          Chemical treatment needs to be done regularly and can take upto 3 years before its erradicated, if there is nothing in the area you wish to keep and there is no chance of contaminating a water source, and its in the early stages of growing, get a dozen or so bags or rock salt, pour the salt about 1/2 thick over the knotweed, and then soak the salt into the ground, as the plant, or any plant absorbs the salt it will kill the plant, becareful of the run off salt water does not enter an area that you wish plants to live. Nothing will grow in the salt treated area for approx 6 -8 months, depending on rain levels. This process needs to be done carefully, as the salt and salt water soaked soil is effectively poisened, and you will probably get a telling off from the local authority, or a civil court action if you poison the neighbors veg patch, the salt method is great on gravel drives and artificial lawns in smaller doses.
           
        • Silver surfer

          Silver surfer PLANTAHOLIC

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          Thank you so much for adding new pics.
          Euphorbia griffithii Fireglow looks a good match.
           
        • Silver surfer

          Silver surfer PLANTAHOLIC

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          Do you want to post pics so we can double check for you?

          Building societies can refuse to give a mortgage if they find it in a garden.

          Eeck...it will grow through tarmac. Through concrete.
          Carpet/tarpaulin will not kill it!

          Do not even attempt to cut it down.
          Do not attempt to try and dig it up.

          Every tiny bit missed will regrow.
          Do not think to dump it or put it in rubbish bins.

          Use "Round Up" when in full leaf and growing strongly with lots of healthy leaves
          Use to exact instructions.
          Do not be tempted to make solution stronger.
          It works slowly by the plant taking in the chemical in and killing from the root up.
          It is not an instant kill like some weed killers seen on TV adverts.

          It may need more than one or 2 attempts.
          Be patient.
          We had it in our old garden in a small area...planted as an ornamental plant in years gone by.
          We did eradicate it.
           
        • Jack2020

          Jack2020 Apprentice Gardener

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          Many thanks for your response. You’ve suggested what my gut instinct was telling me to do by letting it grow and then treat. I now have to work out a way to disguise it from the curious eyes of the walkers going by in their droves due to this current situation. I live on a rural farm road on the outskirts of a popular seaside town which in more mundane times has only one man and his dog passing - once a week! I’ll photograph tomorrow and ask you to confirm if that’s ok. It’s a bit disheartening when I read the stories on the internet but I do want to do the right thing. The area where the shoots have appeared is to be our car parking area and will have to be dug down quite considerably but the thought of disturbing the roots is giving me angst. Still, worse things are happening in the world....
           
        • Jack2020

          Jack2020 Apprentice Gardener

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          Hi I’ve just noticed your reply - sorry I’m just finding my way around the message board.
          You have given me something else to consider re. rock salt. I definitely will not be planting in the affected area and thankfully have no nearby neighbours whose ground I could contaminate. Much appreciate your information.
           
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