To eliminate maintenance and water costs, I replaced my front yard with rocks and 6 Cypress trees. The front yard slopes away from the house toward the street. Since I don’t need to water any plants or trees (the Cypress trees can survive off of rainwater in the Winter), I put down 20-mil thick pond liner. Where two pieces of pond liner meet, I overlap them by 12 inches.
Along the perimeter, I screwed 2x4s into the sides of the concrete using concrete screws. I stapled the pond liner to the 2x4s along the perimeter and then screwed 1.5″ x 1.5″ brown drip edge to prevent weeds from sneaking their way up along the crevices.
If one of your edges is not a standard concrete slab, you may install a short retaining wall. In my case, I made a wall using 12″ wide pressure-treated wood that I held in place using metal stakes. I used brown deck screws that were designed for exterior use to minimize rust and corrosion.
I should have placed the pond liner under the wood before securing the wood in place. Since I didn’t do that, I stapled the pond liner to the side of the wood and then screwed thin wood wrapped in brown plastic (bender board) over the pond liner and into the wood. That should prevent weeds from growing between the wood retaining wall and the pond liner.