Life at the Top: Extensive Green Roof Plant Species and Their Traits for Urban Use

Green roofs are becoming common in cities around the world. Rooftop vegetation faces severe and unique conditions ranging from shallow substrates, high irradiance, water limitation, flooding, extreme temperatures, and strong winds. To benefit the most from this technology for improving urban climate, ecological interactions, and human life quality, it is important to have a toolbox of candidate plant species adapted to the rooftop environment. Herein, an effort was made to provide an overview of the global scenario of green roof plants. A quantitative and qualitative review examining 439 articles published within an approximate 14-year time window (2009 to mid-2023) was conducted to categorize plants amenable to use in green roof conditions, and to identify and discuss their key morphophysiological phenotypic features. This dataset allowed the establishment of archetypal green roof plants for use in different climates. Similar traits were recorded between temperate and continental climate species on one side and between tropical and dry climate plants on the other. The identified set of species and their archetypes within each major climate zone can be useful for readily adopting and expanding new green roofs and as a guideline for incorporating new taxa into this urban environmental technology.