Ornamental Garden Development
An ornamental garden that uses nothing but rain and, barring cyclones, should cope with whatever the climate is likely to throw at us over the next fifty years.
The original plan for the front garden was to showcase water-wise ornamentals. When I realised in 2004 that SE Qld was headed into drought, plans for a garden needing a once weekly watering (my standard design), I decided instead to create a ‘crash test’ rain fed subtropical garden. Long lived plants, like palms and cycads, were chosen to suit the CSIRO’s predictions for Global Warming to 2050.
The native and exotic ornamentals here are not merely water-wise, they are never watered. I foliar feed the garden with seaweed once or twice a year. Only the native hibiscus hedge (Hibiscus insularis, an endangered species from Phillip Island in the Norfolk Island group) needs to be watered weekly during dry spells. This hedge acts as a windbreak, reducing evaporation in the ornamental garden.
In September 2004, I planted 150 plant taxa of ornamental, medicinal and food plants, some of which are threatened with extinction, including palms, cycads, bromeliads, succulents, ferns and bulbs. They were watered six times over five weeks before being abandoned to natural rainfall (which in this part of Brisbane can be erratic).
Unprecedented drought (2005 – 2010) was followed by summer floods (2011, 2012 and 2013) and most recently dry years of 2013 and 2014. These were stressful periods for the garden, and helped reduce planted diversity to 118 taxa.
The reality of drought was erratic falls of brief, dumping rain (often in the winter dry season as a result of East Coast Low Weather Systems), and frosts of 0.5C despite this being a usually frost free district, spring hailstorms, and long periods with no useful rain during the summer wet season.
The heaviest single falls of rain to date were: 56mm rain falling in 16 minutes on 24.1.12, and when 88mm fell in 30 minutes on 11.12.10. In both cases there was no runoff, every drop was absorbed as is normally the case at this property.
The driest dry season to date was winter 2004 (June to August) when the total rainfall was 31.75mm (the average is 176.5mm).
I removed the Agave and the bamboo, Schizostachyum ‘Murray Island’, because they outgrew their allocated space and created unwanted maintenance. In 2014, I removed the Mt Spurgeon pine (Prumnopitys ladei) which was shading the solar panels.
The Coquito de Chile palm (Jubaea chilensis), a threatened species of South American palm and feature plant at Bellis, germinated in 1995. It started producing a nut crop in winter 2011.
Video from a 2007 Gardening Australia Expo presentation