Landscape Screening. To be adequately screened from residential development, a drop box transfer station shall have a perimeter landscaping area of mixed evergreen trees and shrubs that is not less than six feet in width when adjacent to existing public, residential, or commercial uses or public, residential, or commercial zones, including the R1, R2, MF-L, MF-H, POS, MU-O, MU, MU-M, NC, MU-N45, MU-U75 and MU-C110 zones. Landscape planting screens shall be planted according to an approved site plan, with due consideration to seasonal planting conditions, irrigated as necessary, and permanently maintained. All planting material which does not live shall be replaced within the next planting season.