Abstract
Focusing on native plants that have a high possibility of being introduced as extensive rooftop material, this study was conducted to realize extensive and easy-to-manage rooftop gardens and to raise the utilization of native plants by verifying their growing response to soil media and depth. Its result is as follows: 1) In the case of Chrysanthemum zawadskii, the top growth was better in sandy loam than in P$_1$V$_1$P$_2$, and P$_1$V$_1$P$_3$, but the mortality rate was high, making it unsuitable soil. Regarding soil depth the mortality rate was lower in 10cm than in 5cm, and it grew well in 10cm. When using it for rooftop gardens, it would be desirable to keep the minimum viable soil depth over loom. 2) In the case of Sedium middendorffianum the mortality rate was 0% regardless of soil media and depth making it very suitable material for rooftop garden. Although the flowering rate was somewhat lower in P$_1$V$_1$P$_2$, and P$_1$V$_1$P$_3$ than in sandy loam, the mortality rate was low and the root growth was good. Therefore, provided that fertilizing is managed well, it is a plant that can be highly utilized. 3) In the case of Allium senescens, the mortality rate was 0% regardless of soil or soil depth, making it a very suitable plant for extensive rooftop gardens. Although top growth was poorer in P$_1$V$_1$P$_2$, and P$_1$V$_1$P$_3$than in sandy loam the root growth was good. Therefore, provided that fertilizing is managed well, it is a plant that can be highly utilized. In conclusion the study revealed that suitable species for extensive rooftop gardens are Sedium middendorffianum and Allium senescens. However, Chrysanthemum zawadskii can be utilized greatly when fertilizing is managed regularly in artificial mixed soil over l0cm.