Landscaping. For purposes of traffic channelization, precluding parking of vehicles in unwanted areas, and reduction of visual monotony, a minimum of 10% of all parking areas, for 20 or more cars, shall be devoted to raised landscaped islands. The landscaping shall be installed in such a manner that no individual landscaped area shall contain less than 200 square feet; the minimum horizontal dimension of any such area shall be 10 feet. Raised landscaped islands shall be placed such that the ends of all parking bays are defined. No shrubs shall be permitted that are taller than two feet at maturity. At least one shade tree shall be required within each landscaped island.