Evaluate the performance of some plants on different substrate types and depths under various drought conditions in the extensive green roof

Because of the extensive green roof and the special conditions of an environment that is created for plants, the selecting suitable plant species to provide the necessary accuracy. In order to introduction of suitable plant species and investigation of effect of the irrigation treatments and the suitable depth and type of medium, the plants were culture in boxes for five months (July - November) and they were placed on the roof of a building. Selected plants including Ophiopogon (Ophiopogon jaburan), Frankenia (Frankenia thymifolia), Carpobrotus (Carpobrotus edulis) were from three different families. They were placed in boxes with 10 and 20 cm deep including the culture medium with and without peat in wet and dry irrigation conditions. The characteristic of plant morphology were appearance, length and surface area, root and shoot fresh and dry weight. Results showed that the highest quality, coverage and length during the three treatment plants beyond to depth of 20 cm, wet medium irrigation and peat medium. It should be noted that the treatment plants with water depth of 10 cm and medium-dry without peat, in the longer time their quality, coverage and length were acceptable.  Since of the extensive green roof system requires minimal maintenance and less deep, this situation can be considered appropriate. In comparing the three plants, Carpobrotus and Frankenia had better performance than the Ophiopogon. The topic of green roofs in Iran is very new so the importance and necessity of this research is quite clear. This research for the first time did pay attention to the green roof and suitable selected plant species for this system in Iran.