The Woody Meadow project
By Gabrielle Stannus
With the popularity of the prairie or meadow evident during the recent Melbourne International Flower and Garden Show, we take a closer look at how University of Melbourne researchers are developing a local response to this demand.
John Rayner is an Associate Professor and Director of Urban Horticulture within the University of Melbourne’s Green Infrastructure Research Group. Together with colleague Dr Claire Farrell, John has been working to develop a low-input naturalistic planting design suitable for use in public landscapes, based around Australian plants.
The idea for this research was sparked during a conversation John had with Professor James Hitchmough from the University of Sheffield in 2013. Inspired by the London Olympic Park’s annual and perennial meadows, they discussed the possibility of creating a similar design here, one that would be robust enough to thrive in Australia’s challenging climate.
The University of Melbourne then partnered with the University of Sheffield, the City of Melbourne and the Royal Botanic Gardens Victoria (RGBV) Cranbourne to deliver the Woody Meadow Project. The aim of the project was to develop a low maintenance but highly aesthetic 'meadow' landscape using Australian shrubs. Funding for the project came from the City of Melbourne, University of Melbourne and the Trawalla Foundation.
Plant selection criteria
In 2014, University of Sheffield colleague Dr Audrey Gerber completed a literature review evaluating more than 1,200 Australian shrubs against more than 200 criteria. An expert panel of native plant specialists helped to narrow down this list to 287 preferred species. This list of plants was further refined after initial plant coppicing trials of 48 species at the RGBV Cranbourne and the University of Melbourne’s Burnley campus. The final plant list was chosen based on their ability to reshoot after coppicing, to grow well with limited maintenance, provide a long display of foliage and flowers and survive with minimal supplementary irrigation.
“The group of plants we are interested in occur naturally in heathland and woodland ecosystems”, says John. "Heathland plants in particular have well-adapted fire regeneration strategies such as resprouting and reseeding".
The main part of the project includes two Woody Meadow plantings at Royal Park and Birrarung Marr in the City of Melbourne, planted in September 2016. The aim of these plantings was to explore the growth of a mixed community of plants over time and determine whether planting density or species diversity influenced the overall success. 18 x 9m2 plots were created at each City of Melbourne site, using a 200 mm deep scoria substrate.
Over 4,000 plants from 21 species were planted across the two sites. Treatments included Plant Diversity (Low = 12 species vs. High = 21 species) and Plant Density (Low = 33 plants at 38cm spacing vs. High = 63 plants at 52cm spacing). These plantings were irrigated for six months post planting and then most were coppiced to a height of 15 cm in height in April 2017.
At the heart of the Woody Meadow is a layered shrub community. Each plot contained three distinct layers: base (plants ~50 cm in height), bump (plants to ~100cm) and emergent (plants over 150cm). The bump layer provides the main boost of flowering and visual interest. While both base and bump layers were coppiced, the emergent layer was not.
NB. Click here to read more the list of plant species used to create the Woody Meadows.
Results from April 2018 demnstrated that higher density and fewer species produced the best coverage. Good survival rates were recorded (with only 16-21% mortality rate at 18 months). The experiment also found that plant survival was not affected by coppicing or by the plant diversity or density treatments. Distinctive base, bump and emergent layers did develop. However, John acknowledges that only time will show whether these layers will continue to maintain their form.
As for the plants, John says, “The ‘winners’ so far in terms of survival, vigour and flowering have been across all the three layers, This has included the taller shrubs such as Alyogyne huegelii, Eucalyptus caesia, and Acacia acinacea and some of the ‘bump’ layers, especially those with great form and foliage such as Calothamnus quadrifidus and Eucalyptus 'Moon Lagoon'. Some have also been really long-flowering such as Astartea fascicularis while others have successfully suckered and reseeded, such as Dampiera alata and Veronica arenaria. Those with weaker growth across the two sites included some members of the Proteaceae, including Grevillea ‘Coconut Ice’ and Banksia spinulosa subsp. spinulosa.
Together with a number of local councils and state government agencies, the University of Melbourne is applying to the Australian Research Council (ARC) to continue this research work over the next few years. John is hopeful that the outcomes will help develop more locally relevant designs providing resilient, robust and visually interesting plantings in the public realm. “Climate change is upon us. Copying planting design recipes from Europe or North America will not cut it here, we need to develop our own designs that suit our climate and context”, says John.
Opportunities for the nursery industry
John claims that the research outcomes will open a lot of opportunities for under-represented plants, shrubs and perennials to take their place in the market.
“In most urban landscapes Australian shrubs are typically cultivated as poorly maintained specimens rather than as in communities such as the woody meadow. Some of the more interesting plants are unknown in cultivation due to production and horticultural challenges and we would love to see these being grown more widely,” John claims, “Eventually we want to extend plant selection across a broader range, perhaps including Mediterranean plants with natives to create more interesting, attractive and diverse landscape plantings.”