Wikipedia defines sustainability as "the capacity to endure."
To give an analogy, green landscaping is to landscapes what the internal engine is to green automobiles. Similar to the performance of a green automobile, when looking "under the hood" at the performance of the landscape, a green landscape will run longer, leaner, cleaner and meaner than it's conventional counterparts. And, just as green automobiles come with various styles and functionality, green landscaping can have different styling and functionality as well.
A good quality landscape should have all the qualities of styling, functionality and performance -- performance being the "green" quality. A deficit in any one quality compromises the overall quality of a landscaping project. This answer focuses on the "green" quality of performance.
Green landscapes are evaluated on performance. With landscapes being one of the heaviest consumers of water, water efficiency is an important evaluator of performance. Much like fuel consumption of an automobile, water consumption is often the first thing noted about a green landscape's performance.
The four main aspects of green landscaping are the ability to perform:
Within these aspects, performance qualities of a green landscape result in:
Longer intervals between feeding, watering, manicuring, and maintaining mechanical systems such as irrigation, lighting and equipment.
Less input and importation required of water, fertilizer, toxic or non-biodegradable chemicals for biological controls, electricity, and fuel for equipment and maintenance vehicles.
Reduction, elimination or cleansing of sources of pollution such as petro-synthetic fertilizers, toxic chemicals for biological control, petro-synthetic fuels used to operate systems, equipment and vehicles, and other sources of pollution coming from either on or off site.
Improved health, vigor and variety of living systems including soil, plants and animals.
Some of the accomplishments of green landscaping have been:
- up to 70% reduction in irrigation water useage (up to 30% over conventional drip)
- 100% elimination of chemical fertilizer and toxic or non-biodegradable biological controls
- 0% potable municipal water use in irrigation
- 100% irrigation water needs supplied from onsite graywater and harvested rainwater
- Plant growth of 5 years accomplished in 1 year with zero human effort
- Soil health increased 2 to 5 times
- Soil structure and aeration maintained with zero human effort
- 100% hauling green waste away to dump, eliminated
- 0% waste produced
- 100% green waste reused on site to recondition soil
- Plant disease reduced
- Beneficial insect population such as bees and ladybugs increased
- Predatory insect infestations decreased
- Habitat of local native animal population, such as song birds, increased
- Preservation of locally endemic (native) plants included in the landscape to ensure survival of their species
- Preservation of habitat of locally endemic (native) insects and animals who feed on native plants included in the landscape, to ensure survival of their species
- Increased biodiversity, for increased endurance, health and vigor of the landscape as well as preservation of species
...And many more results
I myself like to loosely define green landscapes as being good for people, pets, property and planet.
Programs such as the Bay-Friendly Landscapes in Alameda County, California, educate the public and the landscaping profession on the latest trends and advancements they can use today. The program is geared towards immediate practical application of green landscaping methods and targets working landscaping professionals as well as property owners. It is where "the rubber meets the road", so to speak, and is taught in both English and Spanish.
Policy movements such as the Sustainable Sites Initiative are providing the framework of policy for future advancements of broad application of this knowledge for more people to benefit.