The aim of this research is to enable green roofs in the subtropics.

Cities worldwide are under increasing pressure to provide multi-benefit solutions to urban issues like flooding, heat waves, and the ecological crisis. Green roofs are a complimentary technology alongside other nature-based solutions to introduce nature back into our cities and help combat those issues. Green roofs are encouraged in the northern hemisphere, yet in subtropical Australia guidance and incentives are scarce. This research first assessed subtropical green roof literature to outline the state of knowledge and identify research gaps in the subtropics, as green roof benefits are strongly climate dependent. The resulting systematic quantitative literature review assesses plant performance and impacts of design components on runoff water quality and quantity. Insights from the review were supplemented with expert opinions of practitioners from the green roof industry using an online survey and semi-structured interviews. This mixed method research uncovered further research gaps. While practitioners attributed a high importance to using native plant species, they raised concerns about the availability of performance data, aesthetics, and flammability of Australian native plants. To address the defined research gaps, two experimental field trials were conducted to evaluate the performance of 15 native Australian species in the humid subtropics. [...]