Abstract
The performance of the combination of high density unwoven cloths of which water retention performance is high and a mat plant was estimated. This system is expected as a thin-layered growing system for various kinds of ornamental plants on green roof. The unwoven cloth of 4 cm in thickness was the most effective for growing of Ophiopogon japonicus f. nanus and Phyla canescens among that of 2 cm and other kinds of water retention mats. O. japonicus and P. canescens could grow without irrigation, although they grew best with irrigation of once per 2 weeks or 2 times per week, respectively.