For each mobile home space, there shall be required two (2) trees and four (4) shrubs, at least one-half of which shall be located on the mobile home space. The remaining one-half may be dispersed or clustered throughout the park. In addition thereto, there shall be required two hundred (200) square feet of grassed area for each mobile home space, all of which may be dispersed or clustered throughout the mobile home park. All landscape material shall be maintained in a living, disease- and pest-free manner.