The following shall be exceptions to the provisions of this chapter:
1. Vegetable and/or flower gardens, purposefully planted, shall be permitted if they are maintained.
2. Wood perennials, purposefully planted, shall be permitted if they are planted and maintained.
3. Prairie grass areas, wild flower planting areas, natural reserve and preserve areas, urban wood lots, wild life refuge and conservation areas, wetlands and natural water ways, all as recognized and identified by a governmental agency or a respected private conservation organization.