will gramoxone affect my laurels

Sorry, don't know what gramoxone is. Should be instructions on the pack saying how it works and what you can use it on. In my experience, nothing kills grass that doesn't kill everything else, so the best way to remove is to dig it out. If its couch grass and it's near the main stems, you could try painting glyphosphate on it, having dug out the worst of it as far as possible.