Over Grown in New York

This roof in New York has been left to grow on it's own! This is taking the idea of a green roof to the extreme but also quite logical to just let it grow, possibly a bit of pruning now and again. Lovely. I would love to try this with a town and see what happens over the years. Developing habitats that are more "alive" would be interesting as to cope with the destructive effects natural growths have on most ridged and imposing buildings.