2018 ASHS Annual Conference

Because of their wide range of environmental and economic benefits, green roofs have become important elements of both small and large scale sustainable landscapes. Plant recommendations vary based on the type of system (extensive or intensive), substrate, as well as the geographical location. Sedums generally do well in both types of systems; however, information on which species and cultivars should be recommended in Oklahoma does not exist. The objective of this study was to evaluate nine different Sedum cultivars planted in an extensive system using a 70:30 ratio mix of calcined clay and compost at a depth of 15 cm. Rooted cuttings were planted late March in 2016 in Stillwater, OK in a randomized design with eight plants per cultivar. Plants were watered as needed during the summer and no supplemental irrigation was applied in the winter. Of the eight species and 72 total plants, only 25% of plants survived. Recommended species include S. album ‘Coral Carpet’, and S. reflexum ‘Sandy Silver Crest’, as both had 63% survival. ‘Coral Carpet’ had the greatest growth. Sedum ‘Dr. John Creech’ had 37% survival followed by S. reflexum 'Angelina' and S. spurium 'Fuldaglut' with both having 25% survival. Sedum divergens, S. japonicum 'Tokyo Sun', S. confusum, and S. spurium ‘Tricolor’ did not survive past the first year.