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Couch Grass

Moved into nw house in summer.

Front garden is riddled with couch grass.

Dug it over and removed as much as possible, left to grow and applied glyphosphate once a week for 5 weeks. The surface is now barren but the root structure still dense.

My question is: Will glyphosphate destroy/kill the courch rhyzomes or will it resprout in spring.

The soil is heavily compacted and riddled with root so I was planning to rotavate. If the roots are killed off is this a safe and viable option to help me recondition the soil?



  • nutcutletnutcutlet PeterboroughPosts: 26,160

    Hi anderson, glyphosate doesn't need applying once a week. It works on strongly growing green growth. Respraying something that's already died back, or is in the process of dying back, is a waste of time and money.  A second spraying may be needed if new growth occurs. Don't rotavate til it's really dead, all those little bits will grow.

  • BookertooBookertoo Posts: 1,306

    In fact, I would humbly suggest you don't rotovate at all - I know of no better system for the spread of perennial weeds that rotovation.  We lost an entire allotment plot to having it dug and rotovated, it became a dense mat of dock, mares tail, couch grass and anything else you care to name - we had to abandon ship as nothing could deal with it.   Prevention of light access and patient digging will eradicate the problem, but it does take time and back ache to get there - and does not account for seeds blowing in from elsewhere.  However, no garden or allotment is entirely free of weeds, control however is possible - sort of. 


    Hi Nutcutlet,

    I had heard this but had read that in some cases multiple sprays may be needed. I bought a litre and hope never to need it again so aired on the side of caution with my frivolous application of glyphosphate.

    I plan to leave over winter and see if anything grows in feb-march, then respray if needed and rotavate to aerate the soil before replanting in May.

    Do you think this is a reasonable timescale?

     I have wanted my own garden for years so would really like to get it right first time and not compound the issue. Any advice is greatly appreciated.

  • barry islandbarry island Posts: 1,068

    It will be hard work, believe me I've done it on my overgrown allotment plot. I would advocate digging and removing the roots by hand. After removing it I tried burning the docks, bindweed and couch but found it too damp to burn well without smoking the site out, I then resorted to taking it home and dumping it in the council recycling bin, but I now compost it in a dalek type bin covered with black plastic to keep the light out. It will take a couple of years for it to rot down but after six months it already looks good. 

  • Busy-LizzieBusy-Lizzie Posts: 15,818

    When multiple sprays are needed that doesn't mean weekly. Spray and wait. If there is new growth then spray again. Don't rotovate if there is any chance of any of the roots being alive.

    Dordogne and Norfolk
  • Is it a large patch of unplanted ground?  I have used the old carpet teatment very successfully.  Cover the whole area with an old carpet (you may find one at the council tip) and leave for six months (that's the winter accounted for).  This prevents air and light reaching anything and any real tough weeds and grass will be weakened by the struggle against it.  When you lift the carpet the ground can be dug over and the root removed.  Anything that tries to regrow then can be sprayed with glyphosate. Much of the end of my garden needed this treatment as it had been neglected and become overgrown with couch and bramble.

  • ObelixxObelixx Vendée, Western FrancePosts: 24,934

    Defintely do not rotavate.  It will just make hundreds and thousands of cuttings as the roots are really persistent and grow again form the tiniest bit.   

    Do as advised and spray again in spring when any new growth starts but let it get a couple of inches high before spraying or there won't be enough green foliage to transport the active compounds back to the roots.   Be patient, even if it takes a couple of months and several applications.   It will be worth it.

    When you do eventually dig, use a fork rather than a spade as this will produce fewer cut pieces and allow you to wrestle more or less whole roots out of the ground.    Leave these aside on a plastic sheet so they can dry out and die over a week or two before putting them anywhere near a compost heap or trying to burn them.

    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • So even after a 6 month period of multiple glyphosphate applications the roots have the ability to reproduce?


    This is my main question, does it eventually kill the root?

  • FairygirlFairygirl west central ScotlandPosts: 35,672

    Eventually it will, but as others have said, there has to be enough green material above ground for the  weedkiller to be taken down to the roots. At this time of year there will be very little new growth so you'll need to wait till spring now for any further applications. Dig out roots over winter if you have the inclination, or leave till then  and start a new regime with your weedkiller.  

     It's a very persistent weed, like many others, but the better you have the ground before you plant, the better the result will be. image

    It's a place where beautiful isn't enough of a word....

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