Within the fifty-foot-wide area established in Section 224-113E hereof, there shall be a buffer strip suitably landscaped with grass, ground cover, shrubs and trees and unused for any other purpose except walkways, bicycle paths, gardening, equestrian trails and passive park purposes, including park benches, except that this landscaping requirement shall not apply within any such setback area which abuts an open body of water or public street or where natural wooded areas exist.