Decorative rock is often used to create low maintenance paths or cover French drain systems. A 3-4″ layer of rock covering the ground is typical. If it is designed well, it can seamlessly blend into the landscape and look like it is supposed to be there. Decorative rock is useful for creating paths in dry shade areas where grass will not grow but with too many tree roots that would destroy a concrete sidewalk. This is a great way to get rid of mud and dog traffic related problems. Many different decorative gravels are available.