The green roof concept is gaining traction with builders and the eco-conscious but a successful green roof requires more than just planting some vegetation.
A University of Cincinnati pilot study finds some native plants are more successful in our climate than others.
Student Jill Bader and Assistant biology professor Ishi Buffam were surprised to discover a member of the onion family fared best.
"It looks delicate, I think. The foliage is long and thin and it has a very delicate flower. It doesn't look tough but it is," says Bader.
"It stores a lot of water in the bulb," says Buffam. "It has a storage capacity to withstand a drought and that's its trick."
The researchers say other native plants don't tend to fare as well, though various sedum varieties do.
Read more about Bader and Buffam's work here.