Plastic barrier to keep back the ground elder...?

The cultivated area of our garden is under constant threat from the wild area which is rife with ground elder. We want to put an impenetrable barrier into the soil (vertically, dug in, about 18" deep) to ensure the roots can't creep under the fence and into our flower/veg beds.

Are there any products out there that would suffice? We could use normal heavy-duty polythene, but I'd quite like to find some rigid plastic semi-flexible solution that would last a bit longer and be a bit more impervious to the weeds. Can anyone recommend a suitable product? We'd need about 30m of it, so price is fairly important too.

 

Marko
I also suffer from ground elder and have to keep digging it up. My neighbours have it under the hawthorne hedge and share it regulary with us so I will watch this space for some good advice.I know all the little white roots just produce more.
Good luck with yours.
Jacqui

 

MarcO.
Poly twinwall, the stuff used on conservatory roofs,bought in large sheets and easily cut to size.
I had similar problem with Bind weed and once contained zapped the evil sod with Roundup. Those roots are something else!
Paladin