Place an artificial rock cover over each sprinkler head. Often artificial rock covers are made of plastic and feature an exterior that is molded to look like real stone, but each artificial rock cover has a hollow interior. Remove the artificial rock covers before turning on your sprinkler system.
Block each sprinkler head of a broken sprinkler system with one landscape rock that is 2 to 5 feet wide and tall. Position each rock in front of its sprinkler head so that it blocks the head from the main point of view to that area. Test a rock's placement to hide a sprinkler head by walking down the sidewalk, up the driveway or by the road where the sprinkler head was once visible. Reposition the rock if necessary so it hides its sprinkler head.
Install a rock garden over a garden's sprinkler system that is broken. Lay down an even layer of landscape rocks to cover the area, and use a mixture of large and small rocks to complete the appearance you desire for the rock garden.