As a New York green roof installer I have a special affection for my own green roof. Check it out after all these summer rains. It is bursting with life. I threw a couple handfuls of Native North East wildflower seeds a couple years ago and now the roof overflows with sunflowers both big and small.
This green roof installation really shows a different green roof from your typical low laying sedum roof that resembles more a desertscape. It looks more tropical than anything. But if you pick the right native plants for the mini ecoregion of your particular roof then you can expand the kinds of flora you have on a green roof.