Within the buffer area, a solid and continuous landscaping shall be planted and maintained. The landscaping shall consist of lawn, massed conifer and deciduous trees and shrubs of such species and size as will produce, within two growing seasons, a screen at least four feet in height and of such density as will obscure, throughout the full course of the year, all of the glare of automobile headlights emitted from the premises, except from the driveway. Landscaping within the buffer area shall not satisfy any other landscaping requirement of this chapter.