Landscaping and beautification. Any part or portion of the site, which is not used for building, other structures, loading or parking spaces and aisles, sidewalks and designated storage areas, shall be planted and maintained with an all-season ground cover and shall be landscaped with trees and shrubs in accordance with an overall landscape plan and shall be in keeping with natural surroundings. Any off-street parking area with five or more spaces located between the front building line and the right-of-way lines shall include at least 50% of all required landscaping. The parking areas shall be graded for proper drainage and paved and at least one shade tree, of at least two-inch caliper, shall be provided per five parking spaces or portions thereof located adjacent to the parking area, 8% of which shall be landscaped, the grouping or spacing of which shall be reviewed as part of the landscape plan. A maximum of 70% of the total area of a parcel may be covered with an impervious surface.