Any part of a lot area not used for buildings or other structures or for parking, loading or accessways shall be landscaped with grass, ground cover, trees, shrubs and pedestrian walks. A planting strip of ten (10) feet shall be provided and maintained within the front yard. All areas of the site not paved shall be landscaped with a mixture of trees and grass or any combination of trees, shrubs, flowers, grass or other living ground cover to retard water runoff, restrict blowing trash and deter improper and unsafe access and site use by the public. Trees shall be of three (3) inch caliper measured six (6) inches from the ground level. Street areas not approved for driveways shall be planted in grass. For all buildings there shall be one (1) three (3) inch caliper tree planted for every ten (10) parking spaces to be located within the paved area. Trees shall be spaced approximately twenty-five (25) feet on center across all front yards and thirty-five (35) feet on center in side and rear yards. Foundation plantings shall be planted and maintained along all exterior walls of all buildings at the ratio of one (1) plant material for every ten (10) lineal feet of exterior wall.