Nine years ago, sitting at the top of the site cut for our new house, I found myself gripped with design paralysis. The garden could be anything so what should it be? The house under construction combined bold architectural design with every principle of sustainable building design that we could achieve. Could these principles also be applied to a garden?
Other than in the permaculture world it was hard to find guidance on how to go about designing sustainable landscapes and permaculture gardens appeared to be rather messy. The answer seemed to be to set up a challenge to make a contemporary garden melding bold design and lessons from permaculture. A design with strong bones was born and construction of the Roogulli ‘slow’ garden began.
With the reduce, reuse and recycle jingle ringing loud in our ears and a non-existent budget, the obvious way to begin was to gather piles of salvaged pavers and other materials that seemed useful. Salvaged pavers come in many shapes, sizes and colours and have to be retrieved at short notice. A useful strategy was to set up guiding principles for the materials palette: large format plain grey concrete pavers and smaller reddish clay pavers for paving with attention to paver thickness, red clay bricks for edges. This guided decisions on what materials to collect and which to leave for others. Using the salvaged pavers required skilled construction and creative on-the-spot decisions about paving patterns to accommodate the different sizes and achieve a good looking surface. New pavers are easier but the Roogulli paving is unique.
The Roogulli garden also used large rocks salvaged from site cuts in Canberra to retain the slope of the site cut. This avoided the need to build retaining walls. The resulting rock garden planted with trials of local grassland species and native cultivars has become a key feature of the garden and is home to many lizards.
One of the greatest surprises was the amount and variety of materials that could be salvaged from the dirt left over from the site cut and the key role these materials would play in establishing the identity of the garden. During excavation the topsoil was separated from the subsoil and the two were stockpiled in different areas. When the subsoil was sieved to make mudbricks for the house, various sizes of gravel were left over. The smaller gravel was used on paths and the larger gravel in drainage swales. Fine sieved material from the dirt pile was swept between the pavers instead of quarried sand. All these riches from a pile of rather useless looking dirt!
Curved courtyard walls created sheltered areas in an exposed site. The bold lines and colour of the walls are a key design feature of the house and garden agreed at an early stage with the architect. While the walls are a contemporary design element, their construction from mudbricks rendered with a lime earth plaster is more unusual and involves less embodied energy than a conventional wall.
Roogulli is located near Canberra in a climate with hot dry summers and cold frosty winters. Soils are acidic and devoid of organic material. A sustainable design approach seeks to select plant material to suit the existing conditions and build fertility in soils by encouraging soil biota rather than bringing in huge quantities of materials to amend or replace the soil. It also seeks to incorporate indigenous plant material. The Roogulli house garden uses a diverse range of native plant material grown without artificial irrigation and is constantly full of surprises such as the bright yellow splash of Bulbine Lilies in spring. Lessons have been learned about what species survive and continue to look presentable under these conditions. The planting design continues to develop as more local species and cultivars become commercially available. It is clear that a lush ‘Bali Garden’ will never be possible but it is astonishing how green many of the groundcovers, lilies and rushes remain without watering when the nearby grass is crispy dry.
Irrigation in the edible gardens uses water from the dam pumped using a solar pump to provide much of the food for the household. Here there is constant trial and monitoring of technologies to improve water efficiency. In the dry summer of 2013–14 it is clear that water efficiency for food plants growing in wicking beds is far superior to even the most attentively watered traditional vegetable bed. Increasingly the food production gardens also grow their own mulch, reducing the need to buy in large quantities of mulch.
Heather Venhaus, in her book Designing the Sustainable Site: Integrated Design Strategies for Small-Scale Sites and Residential Landscapes, outlines characteristics of conventional and sustainable landscape design approaches. She contrasts the homogenous, standard template approach of a conventional design with designs that grow from the place and are representative of the local soils, vegetation, materials and culture. As the Roogulli garden developed it came as a surprise to find what a strong local identity was forming through selection of local plant species and re-use of materials from the site at a remarkably low cost in dollars and environmental impact.
While the garden design largely aims to satisfy the aesthetic and functional needs of the occupants, it has been interesting to observe that many other people find this non-traditional garden attractive. The lessons learned in the design and construction of the Roogulli garden are applicable in many other landscape situations. Perhaps there is hope yet for the demise of the cookie cutter, instant suburban garden beloved of fashionable garden magazines and in their place, the rise of resilient gardens with distinct local identities crafted slowly and thoughtfully.