Sustainable landscape construction : a guide to green building outdoors Basic principles : Sustainability in context Principle 1 : Keep healthy sites healthy Principle 2 : Heal injured soils and sites Principle 3 : Favor living flexible materials Principle 4 : Respect the waters of life Principle 5 : Pave less Principle 6 : Consider origin and fate of materials Principle 7 : Know the costs of energy over time Principle 8 : Celebrate light respect darkness Principle 9 : Quietly defend silence Principle 10 : Maintain to sustain Principle 11 : Demonstrate performance learn from failure Sustaining principles evolving efforts.