Aug 20, 2015· 3/8″ River Rock (Pea Gravel) Posted on August 20, 2015 by Valley Landscape Center. ... Smooth rounded rocks between 1/4 and 1/2 inch in size. It can be used around drainpipes and is commonly used in concrete. It is also used for a low maintenance groundcover, in dry creek beds, or on pathways. ... Oregon Block Pavers Price List Castohn Price ...