Online workshop: Green Roof Maintenance

Find link to recording here

In this free online1.5-hour workshop, research experts and practitioners in green roof design and maintenance outlined the key maintenance requirements for a range of Australian green roofs.

Maintenance is critical for functional, flourishing green roofs – ensuring they deliver the long-term benefits for which they were designed – including rainwater capture, biodiversity enhancement and cool, green spaces for people to enjoy.

Participants gained a broad understanding of green roof maintenance considerations as well as detailed information on specific tasks for different types of large and small systems such as roofs for stormwater control, podium gardens and residential projects.


  • John Rayner, Associate Professor in Urban Horticulture, the University of Melbourne
  • Michael Casey, President Australian Institute of Horticulture, Director MJC Horticulture & Evergreen Infrastructure
  • Sarah Hardgrove, Horticulturalist and Landscape Designer, Wildgrove Horticulture
  • Scott Sherwood, Manager Fytogreen NSW and National Maintenance Manager

See more about the presenters here

Is this for me?

This workshop is aimed at a general audience, but will be of particular interest to green roof and aligned industries, and those with an interest in green roof management and maintenance including designers, construction, building owners and managers, developers, planners, landscape maintenance personnel, sustainability professionals, horticulturalists and nursery industry.

About this project

This workshop is part of a part of a University of Melbourne–UNSW Sydney research project Researching the benefits of demonstration green roofs across Australia (GC16002). The project is investigating how demonstration sites can advance the uptake of green roofs and other green infrastructure in Australian cities, developing a knowledge base and range of green roof tools for industry, government and the community. The project is funded by the Hort Frontiers Green Cities, part of the Hort Frontiers strategic partnership initiative developed by Hort Innovation, with co-investment from City of Melbourne, the Victorian Department of Environment, Land, Water and Planning and contributions from the Australian government.



Royal Park Direct Seeding Project

In late April, almost a million seeds of native meadow species were sown across a 1,300m2 area under eucalypts in Royal Park. The Royal Park Direct Seeding Project is a collaboration between the City of Melbourne and the University of Melbourne’s Nick Williams, Steve Livesley and John Delpratt. PhD student Katherine Horsfall joins the team and will be investigating novel techniques and substrates that can best facilitate the germination and establishment of direct-seeded native grassy meadows.

Image: Newly sown native meadow plots along Gatehouse Street in Royal Park, Parkville.

Moving on to new biodiversity ventures

Caragh Threlfall is leaving GIRG for University of Sydney, having received a Commonwealth Discovery Early Career Researcher Award (ARC DECRA) for the project Success and the city: biodiversity responses in urban environments.

Through developing and testing a framework linking urban expansion and biodiversity change, her project aims to identify favourable conditions that support biodiversity in the face of global urbanisation. Caragh has been an integral member of GIRG since 2011, collaborating on a range of urban biodiversity projects including ecosystem services from golf courses, parks and gardens, and the development and assessment of a streetscape biodiversity planting palette. Caragh has also been a Project Leader for the Shared Urban Habitat research stream as part of the National Clean Air & Urban Landscapes Hub. We wish Caragh well in her endeavours and look forward to collaborating with her in future.


PhD News

JULY 2020

Image: PhD candidate Katherine Horsfall at her grassland research plots in Royal Park

Road verges provide ecosystem benefits plus new projects in urban grasslands, how misting can cool cities and stormwater for urban trees.

Congratulations to Adrian Marshall for completing his candidature in which he researched ways to maximise the ecosystem and social benefits of road verges (nature strips). Adrian has published several research papers as well as discussing his work on ABC radio and writing for The Conversation. Find out more about Adrian’s research here, and read a summary of his PhD work.

Welcome to new PhD candidates Katherine Horsfall, Pui Kwan Cheung and Paul Hanley. Katherine is researching direct seeding of native grassland species in urban areas, while Pui Kwan will be investigating the cooling benefits of irrigation and misting in the urban landscape. Paul is looking at how to optimise the design of passive stormwater irrigation systems for urban trees.

Collaborative ecology in public spaces – shared learnings

Collaborative research projects in urban ecology and biodiversity were the focus of a March workshop led by GIRG’s Nick Williams with Prof Alexander Felson (Faculty of Architecture, Building and Planning) and visiting scholar Prof Diane Pataki (University of Utah). Open space managers and maintenance professionals joined researchers at the Melbourne workshop to share learnings and identify new approaches and ways of improving research co-design.

In cities across the world, open space managers and researchers are increasingly working together to co-design and undertake research on public land. These partnerships are an effective way of testing urban ecological theories in real world settings while also generating useful information that can be used by managers to improve open spaces for people and biodiversity. Conducting experiments in public spaces through the creation of ‘living laboratories’ is an opportunity to trial new methods, technologies and plant species. Workshop outputs being developed include a practice note on the elements needed for successful collaborative research in public open spaces as well as academic papers.

Contact Nick Williams

Recent Publications

JULY 2020

Biochar source material matters
Joerg Werdin and colleagues tested the wood of 18 eucalyptus species and found that biochar made from lower density wood was better at storing water and making it available for plants, with implications for the use of biochar as a substrate additive.

Werdin J, Fletcher T, Rayner J, Williams N and Farrell C (2020) Biochar made from low density wood has greater plant available water than biochar made from high density wood. Science of The Total Environment 705. doi: 10.1016/j.scitotenv.2019.135856

What drives green roof invertebrate communities?
Jacinda’s research shows that invertebrate communities of green roofs in Melbourne are driven largely by their surrounding environment rather than the plants they contain. Consequently, the effectiveness of green roofs as invertebrate habitat is highly dependent on location and their horizontal and vertical connection to ground-level habitats.

Dromgold J, Threlfall C, Norton B and Williams N (2020) Green roof and ground-level invertebrate communities are similar and are driven by building height and landscape context. Journal of Urban Ecology 6(1). doi: 10.1093/jue/juz024

Sustainable green roof substrates
Organic waste can lighten green roof substrates, increase water retention, and improve sustainability. This study showed that the addition of coir and compost improved substrates but nut shells adversely affected plant growth, likely due to phenolic compounds.

Xue M and Farrell C (2020) Use of organic wastes to create lightweight green roof substrates with increased plant-available water. Urban Forestry & Urban Greening 48. doi: 10.1016/j.ufug.2019.126569

Assessing green roof substrates
A standard international approach to testing green roof substrates properties is a recommendation of this comparative study of different Australian and overseas methods.

Conn R, Werdin J, Rayner J and Farrell C. (2020) Green roof substrate physical properties differ between standard laboratory tests due to differences in compaction. Journal of Environmental Management 261. doi: 10.1016/j.jenvman.2020.110206

See more GIRG publications

Bringing nature back to cities: Streetscape Biodiversity Case Study

The City of Melbourne has released a comprehensive case study of their biodiversity streetscape research project. The project has illustrated how diversifying streetscape plants can have measurable biodiversity benefits by providing resources such as habitat, food and nesting materials. Researchers Nick Williams, Caragh Threllfall, John Rayner and Jess Bauman have been working with City of Melbourne to design experiments and monitor research plots across four City of Melbourne sites. The Streetscape Biodiversity Case Study details the design approach, budgets, plant species, and the steps and timelines involved. It will be of interest and inspiration to those wishing to undertake a similar evidence-based, collaborative project or anyone wishing to enhance urban biodiversity.

The case study complements the Urban Nature Planting Guide, an online resource for selecting plant species of different forms and drought tolerances that can provide habitat and food for a suite of animals including birds, frogs and butterflies.

Read the Streetscape Biodiversity Case Study

Find out more about this research project here or contact

Image: Lee Harrison, City of Melbourne

Roadmap for Greener Cities

GIRG researchers Nicholas Williams, Kate Lee, John Rayner and Rachael Bathgate have worked with our industry, government and research partners to develop the Roadmap for Green Roofs, Walls and Facades in Australia’s Urban Landscapes 2020-2030. The roadmap sets out the actions for achieving a flourishing green infrastructure industry and more liveable future green cities, and has been produced as part of a Hort Innovation Green Cities project looking at accelerating green roofs in Australian cities. Key actions include establishing a Knowledge Hub, the creation of incentives and mandatory building requirements, and including green infrastructure in government infrastructure planning.

See the roadmap below and find out more about our collaborative research for growing greener cities

Putting Melbourne’s Green Plans into Practice

Dr Claire Farrell took part in a lively panel discussion on urban greening as part of an MPavilion event “Living Melbourne: A Practitioner’s Toolkit to Improve Urban Biodiversity” (Feb 2020). Claire’s co-presenters were Dr Nick Somes (Ecodynamics) and Emma Pryse (Greening the Pipeline). Claire spoke about how the Woody Meadow project could improve urban greening in low maintenance landscapes, especially along roadsides and railway sidings.

Living Melbourne: our metropolitan urban forest is a plan developed by Resilient Melbourne in partnership with The Nature Conservancy (TNC) and endorsed by 41 Victorian organisations representing local government, Victorian government, water authorities, statutory agencies and industry. The strategy details actions for a greener, more liveable Melbourne and presents a transformative approach to respond to urban challenges with nature.

The work of Claire and colleagues in the Green Infrastructure Research Group forms part of the evidence base that will help inform the effective implementation of this important strategy.
Claire is working with a number of local governments on the Woody Meadow project with support from the Australian Research Council. Find out more about the Woody Meadow project here or contact


Global Exchanges – Sweden and China

Amy Hahs joins the China-Australia Young Scientist Exchange Program

Dr Amy Hahs recently visited China as one of 16 Australian Scientists selected to participate in the 2019 Australia-China Young Scientist Exchange Program (YSEP). The Program is funded by the Australian Department of Industry, Innovation, and Science and the Chinese Ministry of Science and Technology.

The trip included a 10-day individual study tour hosted by Prof. Weiqi Zhou at the State Key Laboratory for Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences; and Prof. Jun Yang, Professor of Ecology at the Department of Earth System Science, Tsinghua University. During this time, Amy discussed current research projects and identified areas for future collaborations, with a plan to build towards joint grant opportunities and student exchanges. Amy met up with the other YSEP participants for a closing event in Chengdu and had the opportunity to connect with the Australian Consul-General in Chengdu and the Victorian Government’s local Trade and Investment Office.

Green Infrastructure in Scandinavia

Assoc. Prof. John Rayner has just returned from a five-month sabbatical in Sweden, at the Swedish University of Agricultural Sciences (SLU) in Alnarp, near Malmö. John was based in the Department of Landscape Architecture, Planning and Management (LAPF) where we worked with a small team of research and teaching academics in the Urban Vegetation Group. Continue reading “Global Exchanges – Sweden and China”

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