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eek , what is this worrying weed

berardeberarde Posts: 140
I noticed that my phlox had green leaves coming up, but today I wondered why it had now come up well outside of the crown and looking further it had spread and to nearby plants, and they weren't phlox leaves so then realised this was a weed and with runners a milky white and an extensive root network I'm rather concerned that it is something pernicious. I am sure it wasn't there last year so must be new and I hope not too embedded as some of the runners were going into adjacent plants. I straight away checked Jap knotweed, Himalayan balsam, but doesn't look like them, bit could it be himalayan knotweed? I'll be on a daily lookout and have some glyphosate in the garage


  • josusa47josusa47 Posts: 3,530
    From the foliage, I'd guess one of the willowherbs.  Take care with the glyphosate that none of it gets onto your cherished plants.
  • nutcutletnutcutlet Posts: 27,142
    it isn't any sort of Knotweed, they have alternate leaves, these are opposite.
    Himalayan Balsam is an annual, it doesn't have runners
    Have you got a photo of the plant growing, no hands distorting the shape?

    In the sticks near Peterborough
  • berardeberarde Posts: 140
    Thank you
    I haven't got photos of it growing as I pulled it all out. Yes it does look as though it may be a willowherb. I'd only ever heard of rosebay willowherb which I do get in the garden, but it comes up as single plant which pulls out easily with no spreading roots so I assumed it was an annual. So this may be a different variety as it has come up in a rapidly spreading clump with a lot of roots running.
  • josusa47josusa47 Posts: 3,530
    Wikipedia lists almost 200 species of willowherb!  Luckily, most of them don't grow in the UK.
  • berardeberarde Posts: 140
    Ok it took me most of the morning as it had spread over about a diameter of about 2 feet and around 9 inches down. I removed 4 of my plants,  it hadn't got too deeply into them, forked out as much as I could and then riddled the soil twice over and replaced it.

     I thought about black poly, but the GW website says that it dies off with pulling repeatedly. I think it must have been in the phlox that I bought and planted last autumn as I never saw any when I did a fairly major revamp of the garden last autumn. 

    What alarms me though is just how much it had spread; supposing it got going a bit in the Autumn and that it is only mid spring now it must have grown at a startling and worrying rate. I guess now it is a case of checking daily.
    I'm surprised it doesn't figure more prominently in the lists of bad weeds. I hope that mostly deals with it.

    I'm not sure it is rosebay willow herb as I often get that coming up singly and they seem easy to pull out. (maybe what I have always thought is rosebay isn't)
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