Using a small Border Fork just keep plugging away and get all those Couch Grass roots out now, while the weather is dry. There is no easy solution. I am still clearing them in a 20 pole allotment. Its called ' winning your plot' - the soil you end with is your treasure.

You do need to get the roots out - if you can manage it, use a full sized garden fork for digging rather than a border fork and extract as much root as you can. Border forks are sometimes the only option if digging is difficult for you, but the tines aren't long enough for something like couch grass. There is no herbicide that will kill off couchgrass, its been withdrawn. If the couch grass has grown in amongst other plants you want to keep, then the best you can hope for is control by hand pulling around the base, but for smaller plants, you can dig those up in autumn, extract the couch roots, and replant immediately. Repeated applications of glyphosate may have some impact, but it works much better on broad leafed plants than it does on grasses, so be careful you don't get it on the leaves of any plants you actually want to keep. You needn't worry about getting it on the woody base of plants though, glyphosate works 'through the green' and won't work on wood.

Hi, thanks for the tip green fingered friends. this is in a relatives amazing barn convention garden, she has lent my family for one month as we are in between moving house. As a thank you I am tackling her overgrown garden as she works at sea.
I am super fit and have done a good 8 hours digging I reckon there's another 10plus to finish the major grass extraction. My question is , to make it as low maintenance as possible for her should I put a membrane down then a thick layer of bark or just bark? I have taken out all the major roots so it's just the micro roots that would take a lifetime to weed.

Many thanks Ronan

Membranes have tiny drainage holes in Ronan. The Couch Grass roots will grow again through them, and need Glysophate spraying, if you want to use that method. They die off eventually.
Bark chippings go rotten in 3 years.
I still advocate the border fork as I am 5'1" tall, and use a sharp spade for the deep bits. Best now the ground is drier. I have spent hours picking these awful roots out of soggy wet soil.
This summer weather has made the problem worse.

I'd use a root barrier, but not the really thin weed membrane commonly available, often on rolls, use the thicker grade one,usually sold by the length at the garden centre, looks black and shiny. Still weed membrane, but lasts longer and is thicker... then mulch over the top, or just put soil over it, whichever.

Hi, thanks again for your tips. I know that membrain has holes in and roots will eventually come through and that a thick layer of bark will help with weeding as they have a long root.
I measured up today I've cleared 30m2 there is still a lot todo. For what I've cleared I need 20 bags of bark , so I'm just fishing for the best method , do it properly once and all.
What's glysophat spray ? I have been thinking of sprays but have never used them didnt realy want to go down that road. Must it be done before the membrain gose down ? Dose it harm other plants ? Can it be re applied ?
would like some advise on the most cost effective plant buying method for shrubs/bushes flowering and just nice leaf colour and shape. Was at a garden center today but had limited time just a brisk walk round , all a little dear I'm thinking small plants in groups that will grow in time. Will do a bit more research with what plants I'm thinking of and get back to see what you all think.
Thanks again and I'll keep on digging

Glysophate Spray kills the root systems of weeds, and everything else within a 3 ' radius. So be careful.
I would get the strong membrane, cover with a ton of gravel which you can buy in bags now, cheaper to take home in the car boot. Buy half barrels or cheapest large containers, and best compost. Choose the shrubs when you have more time to think about the various coloured leaves. Evergreens keep their colour all through the winter, but some need acid compost.
Take advice from GC staff about this. Cover compost in containers with bark chippings, saves watering.
Study Goyers' gardens for decorative ideas to make a long term low maintenance effect. I have learned a lot from them.
Good luck.

Glyphosate is the active ingredient in Round Up - but Round Up has other ingredients which cause trouble in the environment. You can buy straight Glyphosate (as Tumbleweed, or places like Wilkinsons sell their own generic version). Add a squirt of washing up liquid (helps it to stick better) to it when you've mixed it - its much cheaper than buying Round Up, and ecologically better. Even so, still works much better on broadleaved plants, not grasses.