Where a perimeter strip is required by special permit, there shall be provided along such abutting lines a perimeter strip having a minimum width on all sides adjoining other parcels of 25 feet, provided that this strip does not apply to front yards. This strip is in addition to all side and rear yard requirements and shall be developed, used and maintained for lawn, shrubs, trees and bushes to the end that such strip shall afford a screen at least six feet high effectively barring visibility. The perimeter strip is intended to remain inviolate of any other use, including piling, plowing or storage of snow.