Common toadflax (Linaria vulgaris) is an excellent plant on green roofs. However it is vulnerable to drought and therefore needs to be in at least 150mm to really flourish. A good tip is to plant between a couple of logs. The logs provide a little shade and protection form the wind. [...]
Thrift is a coastal plant thriving on cliff and cliff tops. Thriving in such stressed conditions makes it ideally suited to green roofs.
It is spectacular plant and it is worth planting plugs of the species in groups of ten or more to give a good carpet effect on the green roof.
Mignonette (Reseda lutea) is a native berb that has dense terminal spikelike clusters of yellowish white flowers. The scent of the flowers is an intense spicy fragrance. It is a good green roof plant, where the substrates are deeper than 100mm.