Eco green roofs have just competed the semi-intensive roof on BSKYB head offices. The roof consists of 450m2 wildflower and shrubs. There was a mixture of 20 different native wildflowers suitable for a green roof. The green roof growing medium was 200mm deep and this was to offset some of the buildings requirements to slow the water leaving the building.
As you can see from the photos the green roof looks great.