Ecosystems as Models for Plant Selection on Extensive Green Roofs in Southern Ontario

Research on green roofs has shown their potential to moderate stormwater runoff and excessive heat in large cities. This has supported the implementation of a bylaw in Toronto, Canada which mandates large scale green roof construction. However, designers lack knowledge on appropriate plant selection for local green roofs. European research has demonstrated that healthy plant cover can significantly improve stormwater capture and cooling on green roofs. This thesis employed two methodologies to select native plants suitable for green roofs. Plants species were first identified from Ontario ecosystems with conditions similar to extensive green roofs including alvars, rock barrens, talus and cliffs. Secondly, plant surveys of existing extensive green roofs in Toronto and other southern Ontario locations to discover plant species already in use. Formal testing of the plant species generated from both methodologies can eventually provide designers with knowledge of dependable plant assemblages for extensive green roofs in Toronto.