The document discusses sustainable design principles for small landscapes, emphasizing the importance of functional, maintainable, environmentally sound, cost-effective, and visually pleasing designs. It outlines key design principles such as unity, simplicity, variety, balance, emphasis, sequence, and scale, along with considerations for plant selection based on sustainability. Additional design tips for small landscapes include designing for multiple purposes, interplanting ornamentals with edibles, and considering views while ensuring proper maintenance.