1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Please note - to keep GC running smoothly, from time to time the staff will have to close a long thread and continue it in a new thread. You too can do your bit to help - if you have a long running PM conversation, please terminate the conversation and start a new conversation. For further information, please contact a member of the staff team.
    Dismiss Notice

Japanese Knotweed near veg patch

Discussion in 'NEW Gardeners !' started by Proper_brew, Apr 21, 2017.

  1. Proper_brew

    Proper_brew Apprentice Gardener

    Joined:
    Apr 21, 2017
    Messages:
    4
    Gender:
    Male
    Ratings:
    +5
    Howdy my green fingered wizards.

    I have a gravelled garden with slightly raised beds that go into the soil under the gravel membrane. There is a small cluster of knotweed coming under the fence at the very back of the garden ~5metres from the frontline of the closest bed. We live in an area of heavy clay soil.

    My questions are:
    Will it eventually creep and overtake my beds or just stay quietly in its corner if i just cut back growth? (No weedkiller or smother tactics)
    And
    Is it okay to grow veg and edible food this close? Bearing in mind the suspect area may have been saturated with an unknown ammount of shop-bought weedkiller (not a drop of weedkiller used since ive been in property which is 1yr 6m)

    Apologies if they are naive questions.

    Thanks.
     
    • Friendly Friendly x 1
    • Zigs

      Zigs Naughty Ginger Admin Staff Member

      Joined:
      Jun 10, 2010
      Messages:
      42,892
      Gender:
      Male
      Occupation:
      Historic Building Conservator
      Location:
      GCHQ Zone 9a Dorzet
      Ratings:
      +53,404
      Welcome to Gardeners Corner :sign0016:

      No such thing as a naive question :)

      It's something you really ought to spray off, it won't stop advancing and it can take £20,000 off the value of your house :yikes:

      Cutting back is dodgy too, you run the risk of spreading it thru vegetative reproduction, and it's controlled waste, you can't just take it down the tip.

      See if you can find out if its been treated by the person that owns the land its coming from :fingers crossed:
       
      • Like Like x 2
      • Agree Agree x 2
      • Marley Farley

        Marley Farley Affable Admin! Staff Member

        Joined:
        May 11, 2005
        Messages:
        27,346
        Occupation:
        Gardener Councillor Governor Homemaker
        Location:
        Under the Edge Zone 8b
        Ratings:
        +7,730
        Oh dear not the gardeners friend at all.. I would cut and burn any stems left from last year and then spray it off with Roundup tree and stump killer.. It is a very voracious weed that people will turn their back on if possible as difficult to eradicate.. If it was me I would erect a screen around it so there is no over spray drift off..! You may need to spray several times as new growth pushes through..
        If it is coming from someone else's land un controlled it is notifiable to local council..
        Not something any of us want and need to get rid of ASAP..! :dbgrtmb:
         
        • Agree Agree x 2
        • Like Like x 1
        • Mowerman

          Mowerman Gardener

          Joined:
          Jul 26, 2015
          Messages:
          435
          Gender:
          Male
          Ratings:
          +588
          It will thrive in all kinds of soil and will spread no matter how heavy the clay soil is. Doesn't seem so formidable in really sandy soil for some reason.

          Firstly - don't cut off the growth. The root system will likely have energy reserves to keep sending up new shoots for years before lack of photosynethis kills it off. If it has crept from a neighbouring property, this 'smother' approach is doomed to failure as it will get a source of light from elsewhere. The waste is seriously dangerous too and if an erradication expert is needed, they will have to assess the infestation and the best indicator to the relevant course of action is the foliage.

          Like @Zigs and @Marley Farley suggested - you need to establish whether it has come from a neighbour's garden, private or council-owned land etc before considering the next course of action.
           
          • Like Like x 1
          • Agree Agree x 1
          • Informative Informative x 1
            Last edited: Apr 21, 2017
          • Proper_brew

            Proper_brew Apprentice Gardener

            Joined:
            Apr 21, 2017
            Messages:
            4
            Gender:
            Male
            Ratings:
            +5
            Thanks for the input guys. Current sit-rep is:
            Gave it a tactical strike of weed killer down a severed stem. And stuck all the remains in a heavy duty bag to dry and burn.

            I should probably mention that i do not own the property, i am currently renting. So i am not overly keen on venturing into all out war on a property i will not be in permenantly.

            Notably all sides of the garden are concreted: Neighbours, passageway and driveway respectably. Interestingly the neighbours beyond the passageway have grown a wall of bamboo along the border of their garden. So i have a feeling the landlord has simply gravelled over the problem, and my garden is ground zero :sad:

            That being said can i get as much as i can from the beds until they are compromised, If this is a viable option? And then change to pots and freestanding planters. Shall inform landlord and update.

            Thanks again guys.
             
          • ARMANDII

            ARMANDII ADMINISTRATOR Staff Member

            Joined:
            Jan 17, 2011
            Messages:
            37,691
            Gender:
            Male
            Occupation:
            Semi-retired
            Location:
            West Cheshire
            Ratings:
            +42,308
            "Control


            Non-chemical controls
            When tackling Japanese knotweed, cultural control methods pose some problems;

            • Digging out is possible, but due to the depth that the rhizomes can penetrate, regrowth usually occurs. This method also creates problems over disposal as Japanese knotweed is classed as 'controlled waste' under the Environmental Protection Act 1990. This requires disposal at licensed landfill sites. Specialist Japanese knotweed contractors are usually licensed to safely remove the weed from site but check first before employing their services. Alternatively, it can be destroyed on site by allowing it to dry out before burning. On no account should Japanese knotweed be included with normal household waste or put out in green waste collection schemes
            • If digging out is attempted, remove as much root as possible, then repeatedly destroy regrowth. In this way the energy reserves in the remaining underground parts will be gradually exhausted; a process which may, however, take several seasons
            Biological control
            • A plant sucker (psyllid) is being released in the UK as a biological control for Japanese knotweed. It is currently only being released at a handful of trial sites and is not available to gardeners. However, if successful it will be released more widely and will become widespread in Britain over the next five to ten years by natural spread
            Chemical controls
            When using weedkillers, always follow the instructions on the pack to make effective and economic use of the product while minimising risks to people and the environment.

            Glyphosate
            • Perhaps the most effective and simplest method for the home gardener to tackle Japanese knotweed is with the glyphosate-based weedkiller Scotts Roundup Tree Stump & Rootkiller. This has label recommendation for controlling Japanese knotweed, instructing it to be applied to the cut canes. Bayer Garden Super Strength Weedkiller also has label control for this weed
            • Alternatively, try other tough formulations of glyphosate (e.g. Scotts Roundup Ultra, Bayer Garden Rootkill, Doff Maxi Strength Glyphosate Weedkiller or Westland Resolva Xtra Tough Concentrate)
            • Glyphosate is usually applied to the foliage and is passed within the plant to the underground parts
            • It is useful to cut away old stems during the previous winter to allow good access. As with other weeds, the most effective time for spraying Japanese knotweed with glyphosate is at the flowering stage in late summer. However, it is difficult to spray at this stage, when the weed is 2.1m (7ft) or more high
            • A more practical approach is to allow Japanese knotweed to grow to about 90cm (3ft), which will usually be reached in May, and spray then. There will be regrowth and consequently a second application in mid-summer is useful. Check during September and if it has grown once more, spray again before growth begins to die down in the autumn. Check again the following spring
            • Avoid spray coming into contact with garden plants. Glyphosate-treated knotweed will often produce small-leaved, bushy regrowth 50-90cm (20in-3ft) in height the following spring. This is very different in appearance to the normal plant and it is essential that this regrowth is treated
            • It usually takes at least three to four seasons to eradicate Japanese knotweed using glyphosate. Professional contractors, however, will have access to more powerful weedkillers that may reduce this period by half
            Residual control
            • The residual weedkillers Bayer Garden Path & Drive Weedkiller and Scotts Weedol Pathclear products containing glyphosate/diflufenican in a soluble sachet. They may provide a moderate check in growth, but because of the extremely persistent rhizomes, is unlikely to eradicate the weed."
             
          • ARMANDII

            ARMANDII ADMINISTRATOR Staff Member

            Joined:
            Jan 17, 2011
            Messages:
            37,691
            Gender:
            Male
            Occupation:
            Semi-retired
            Location:
            West Cheshire
            Ratings:
            +42,308
            "What is Japanese knotweed?


            Japanese knotweed is a strong-growing, clump-forming perennial, with tall, dense annual stems. Stem growth is renewed each year from the stout, deeply-penetrating rhizomes (creeping underground stems).

            New legislation
            An amendment to the Anti-social Behaviour, Crime and Policing Act 2014 includes Japanese knotweed and other invasive non-native plants. Full details of how this will work for the homeowner are not yet available, but here are some key points:

            • It is not illegal to have Japanese knotweed in your garden
            • On your property, you should aim to control this plant and other invasive non-native plants such as Himalayan balsam and giant hogweed, to prevent them becoming a problem in your neighbourhood. If they have a "detrimental effect of a persistant or continuing nature on the quality of life of those in the locality", the legislation could be used to enforce its control
            • Control can be carried out by the homeowner (see the control section below) and doesn't require a specialist company. However, a specialist company will be skilled at control and can dispose of the plant waste
            • Identification is important. Japanese knotweed can be confused with other plants including Persicaria microcephala (e.g. P. microcephala 'Red Dragon'), Leycesteria formosa and Houttuynia cordata
            • Where problems with Japanese knotweed occur in neighbouring gardens, we suggest that you speak or correspond directly with your neighbours (who may already be taking action to control this difficult weed). These informal steps should be taken before contacting your council to talk about control using the legislation
            For more information, see the Home Office Information Note: Japanese knotweed."
             
          • pete

            pete Growing a bit of this and a bit of that....

            Joined:
            Jan 9, 2005
            Messages:
            23,083
            Gender:
            Male
            Occupation:
            joinery
            Location:
            Mid Kent
            Ratings:
            +17,150
            About to get shouted down,:biggrin: but I know of quite a few clumps of this, which for years, have only very slowly gained in size.
            Personally I think it is the frenzy that the plant causes that creates the problem.

            Builders are probably the plants biggest propagators.

            Worst thing you can do it to try digging it out.

            I'd say weedkiller is probably the best way to go, but if it was me I'd just cut it down and burn it when it has reached full growth in each season.
            Then keep an eye on how much bigger the clump gets the next year.

            Weedkiller is expensive and you will need a lot of it.
             
            • Like Like x 1
            • Mowerman

              Mowerman Gardener

              Joined:
              Jul 26, 2015
              Messages:
              435
              Gender:
              Male
              Ratings:
              +588
              It depends on how much time, money and effort you are willing to put into the eradication.

              As you're renting, it's your landlords responsibility to get the matter resolved. It's in his/her's interests to do so as the stigma surrounding Japweed can devalue the house price significantly. The very fact it is present on the property (or surrounding properties) will rule out mortgages from many lenders.

              If it has crept in from surrounding land, the landowner may face an expensive bill or large insurance payout.

              But if you want to tackle it alone and have a hundred quid or so and a few hours to spare (solely for the equipment and products needed to knock it back/kill it), I'd be willing to point out in this thread, the best way to make a start. Whatever you do - PLEASE don't chop it down or dig any of it up!!! :wallbanging: :thud:
               
              • Like Like x 1

              Share This Page