If your yard has existing grass and sprinklers you can have curb put in. There are a couple things to be aware of though. Existing yards are considered a retro-fit, done after the fact. Normally curb goes in before the sprinklers and rock or mulch so the curbers can create smooth flowing lines without obstruction like sprinkler heads ect. Since they are already in along with the plastic or brick edging, the curb may go outside those areas and create new lines. Curb can easily be placed outside the sprinkler heads and not obstruct spray that way we can create smooth, beautiful flowing lines. The space behind the curbing then can be filled with your material.