Prior to the granting of any planned unit development, the Council may stipulate such conditions and restrictions upon the establishment, location, design, layout, height, density, construction, maintenance, aesthetics, operation and other elements of planned unit development as deemed necessary for the protection of the public interest, improvement of the development, protection of the adjacent area and to secure compliance. In all cases in which planned unit developments are granted, the Council shall require such evidence and guarantees as it may deem necessary as proof that the conditions stipulated in connection therewith are being and will be complied with.