A better way would be to carve out the shape of your choice on the ground, dig it out to the required depth, pat all the stones down evenly, choose a quality pond underlay to lay down next and then a thick pvc overlay such as butyl which has good strength and elasticity. Place another layer of pond underlay on top again and then spread down enough soil for plants to root into. This sandwich layering makes it more difficult for anything to perforate it.
fast growing hedging