This study was carried out to assess the covering of 11 Sedum species on an extensive green roof system under the urban climate of South Korea for 2 years. The eleven Sedum species which came up to the criteria were selected: S. acre, S. album, S. kamtschaticum, S. oryzifolium, S. polystichoides, S. reflexum, S. rupestre, S. sarmentosum, S. sexangulare, S. spurium, and S. telephium. The plants were planted in the extensive green roof system with the substrate of porous glass+bark+field soil (v:v:v, 3:2:5) and then evaluated. The covering area of the Sedum species were about 72㎠ at the start after the establishment. When a year had passed since the systems were established, S. acre, S. oryzifolium and S. sexangulare maintained 200-500㎠/plant of covering area and the others maintained 800-1200㎠/plant. Most covering area increased continuously for about two years and showed a large quantity of increment in summer season with the exception of S. kamtschaticum, S. polystichoides, S. sarmentosum, and S. telephium, whose above-parts were not alive in winter.