Using edging on a garden path defines the personality of a path.   It helps keep the material in the path secure and also helps grass from growing into your path.  Many materials may be used to define the edges.  You can use Stone or Rock Edging, Block Edging, Flat Stone Edging, Brick or Paver, metal or plastic edging.

 

Flat Stone Edging

Paver

Rock Edging

Stone Edging