Landscaping should benefit and enhance the environment, not potentially harm it. The importance of environmental soundness in design comes right after function and maintenance.
A design with the right plants in the right places will reduce or eliminate the need for fertilizers and pesticides because these plants will have less stress and be less susceptible to nutrient deficiencies and insects.
Resources should not be used to fight against the climate, soil, insects, light or wildlife. Instead a design should operate in harmony, taking into account and emulating the successful ecosystem that already exists.
GOOD ENVIRONMENTAL DESIGNS
Incorporate food, water and habitat for native wildlife.
Use hardy local plants to eliminate the need for additional water, fertilizer and pesticide.
Do not use invasive species.
Keep lawn size below 25% of the total irrigated area.
Reduce impervious surfaces.