Landscaping. All public off-street parking areas serving five or more vehicles and created or redesigned and rebuilt subsequent to adoption of this chapter shall be provided with accessory landscaped areas totaling not less than 5% of the surface area. The minimum size of each landscaped area shall be 100 square feet. Location of landscaped areas, plant materials, protection afforded the plantings, including curbing and provision for maintenance, shall be subject to approval by the Plan Commission. All plans for proposed parking areas shall include a topographic survey and grading plan showing existing and proposed grades and location of improvements. The preservation of existing trees, shrubs, and other natural vegetation in the parking area may be included in the calculation of required minimum landscaped area. Parking areas for five or more vehicles which adjoin residential districts shall be visually screened with a solid wall, fence or evergreen planting of equivalent visual density or other effective means, built and maintained to a minimum height of six feet.