It’s our view that every landscape design should follow sustainable principles. It is possible to take our cue by studying the way in which natural ecosystems are organized. We could take one of many natural ecosystems as a model, but the figure below shows a patch of Mallee scrub in South Australia. The soil here is poor (it is low in phosphates and trace elements) and the rainfall is less than 350 mm per year. One species of Eucalypt (a multi-trunk tree) dominates the upper story, 2-3 species, an Acacia and Senna artemisoides are the mid-level shrubs and Spinifex grasses and Blue Bushes (Kochia sedifolia) make up the understory plants. Note the bare areas where competition keeps plants from establishing.
The figure below shows a designed and constructed landscape. The selection of species, placement, etc. is modeled on the above. Here a sustainable landscape has been created – one in which the plants are adapted to the local soil and climate conditions so no additional fertilizer or watering is required. The landscape sustains itself, just as the natural one does.
There are certainly many other aspects of landscape design where attention to sustainability principles is important.
So, to sum up, a sustainable constructed landscape:
• Is designed to suit local environmental conditions.
• Contains carefully selected water-wise plants.
• Contains plants that will not become environmental weeds.
• Conserves water using mulch, efficient irrigation, watering only when necessary and grouping plants with similar water needs together.
• Provides habitat for local native fauna such as small birds, butterflies, bats, lizards and frogs.
• Avoids use of pesticide or other chemicals that could harm the beneficial organisms or contaminate soil and water.
• Consumes minimal non-renewable energy in construction and maintenance.
• Uses sustainable and locally sourced materials and products, and avoids materials such as rocks, pebbles or wood collected from wild landscapes.
Our landscape design software (gCADPlus) allows access to a sustainability calculator to help in that regard. Here is the link.
You may find that running through the following checklist upon completion of a design useful.
Has existing vegetation on and within 3m of site boundary been identified to the genus and species level?
Have all recognized environmental weeds, if present on the site, been indicated to be removed?
Does the Plant Schedule cover all information required by the local planning authority? (see layout)
Have tree protection, maintenance, planting, garden bed preparation notes been included?
Are indigenous planting requirements met? (50% and above)
Are permeability requirements met? (75% and above)
Have you checked the planning overlay for any permit requirements or authority approvals?