When the county council shall find that it is required for the purpose of safeguarding the health, safety and welfare of surrounding residential development, then, in that event, the operator of any drive-in theater shall provide a wall or fence of adequate height to separate the patrons and cars in attendance in the theater from surrounding property. The fence shall be of substantial construction made of wood, metal or masonry and erected solely upon the property used for the outdoor theater proposed, in accordance with the requirements specified by the director, but it shall not be treated as a partition or line fence. The outside of the fence, as far as possible, shall be landscaped with suitable plants and shrubbery to preserve harmony with the appearance of the surrounding property. (Mont. Co. Code 1965, § 75-25.)