For all uses that include areas used for service, loading, and unloading activities, such areas shall be screened along the entire rear lot line and side lot lines from the rear lot line to the rear building line to the following minimum standards:
(a) The width of the screening area shall be a minimum of five feet. Screening shall consist of walls, hedges, fences, vegetation, or an acceptable combination of these elements, provided that screening must be at least six feet in height.
(b) Vegetation used for screening shall have a minimum opaqueness of 50 percent at all times within two years of planting.