(a) No wall, fence, or opaque hedge or screening material higher than thirty-six (36) inches shall be maintained within a required front yard in a PO zone.

(b) A decorative masonry wall at least six (6) feet in height shall be erected along all property lines which lie immediately adjacent to any residential zone, except that alternative screening may be used which may include a landscape hedge of six (6) feet at a two (2) year maturity, wood fence or a combination of landscaping with chain-link, with or without slats. In the case where there is mutual agreement by adjoining property owners and approved by the Planning Commission or its designee, this requirement may be waived.