There are many advantages of green roofs other than just looking good. They help to stop the rain gushing down and therefor stop storm water runoff as well as keeping the building cooler indoors. The benefit to humans and animals is that the plants process the carbon dioxide from vehicles and produce oxygen, without which we would not live. They retard fires and help to reduce both noise and air pollution. Once planted up, they will require watering or irrigation until such time as the plants have established themselves. Choose drought hardy plants that will be low maintenance like the succulents. They also have a large variety of leaf shapes and colours which make them interesting. Consider the Cotyledon, Crassula, Kalanchoe, Kleinia, Othonna and the Lampranthus families. One could also use flat growing Aloes and they would supply nectar to the sunbirds. The hardy Tulbaghias, Bulbines and the emerald green Asparagus would also look lovely. Portulacarya afra prostrata is perfect for the edges and it has this pretty, cascading habit. One could also emulate an English meadow using our indigenous grasses with bulbs interplanted. If one plans it carefully, there could be some flowers throughout the year. In Spring one would have the Aloe cooperi and Crinums booming. In Summer there could be Aristea, Bulbine, Kniphofia or Merwillea plumbea. Winter flowers are the Cyrtanthus and Tulbaghia while Autumn is the time to see Gladiolus daleni and Aloe dyeri. These would create biodiversity and attract birds and insects as well as admiration from passers by.