Landscaped areas and sections, including trees, shrubbery, fences, and the grounds in and surrounding these sections, shall be properly maintained throughout the twelve-month period following certification, with recourse by the City to the performance bond in the event of default by the developer or owner. All plantings which fail to survive for a period of 12 months following certification shall be replaced by the developer at no cost or expense to the City or the municipal agency. Such replacement shall be made within 60 days following written demand for such replacement from the municipal agency, or within such extended periods as may be specified. If the developer refuses to do so, the City shall have recourse to the performance bond to remedy his default.