Unenclosed uses. Any use, required by this chapter to be landscaped, which is not conducted within a completely enclosed building, such as required off-street parking, shall be screened by a solid or closely woven fence or by evergreen hedges or shrubs spaced at intervals of not more than five feet, located and maintained in good condition, within 10 feet of the property line or the zone district boundary line or as shall be determined by the Planning Board. In the alternative, the Planning Board may require a landscaped earthen berm not less than five feet in height.