All construction, alteration or enlargement of nonresidential structures or multifamily structures shall require a planted buffer area when such use adjoins single-family dwellings. The purpose of the buffer area is to provide a visual screen to separate the impacts of nonresidential use and/or disproportionate building bulk to adjoining single-family residents. The buffer area may consist of preservation of existing natural mature plant growth, new plant materials, fencing or any combination of the same to ensure proper separation of one use from the other. This regulation shall apply to all districts unless specifically regulated elsewhere by zone district.