If the council shall fail to pass an ordinance proposed by initiative petition or shall pass it in a form substantially different from that set forth in the petition therefor or if the council shall fail to repeal an ordinance for which a petition for repeal has been presented, the adoption or repeal of the ordinance concerned shall be submitted to the electors not less than thirty days nor more than one year from the date the council takes its final vote thereon. The council may, in its discretion, and if no regular election is to be held within such period, provide for a special election. All county councils shall be bound by the results of any such referendum.