Landscaping. Screen planting of a dense evergreen material not less than four feet nor more than six feet in height shall be provided in off-street parking areas for more than six vehicles. In lieu of screen planting, a fence or woven lattice, masonry wall or wooden louver-type or split cedar fence with a maximum of three-fourths-inch spacing may be provided not less than four feet nor more than six feet in height, maintained in good condition and without advertising. This provision shall not apply to the industrial districts except where industrial districts border on a residential district.