May 3th, Heintz - Pittsburg, a very urban green roof

Covering 12,000 square feet or slightly more than ¼ of an acre, this extensive green roof uses a two layer Roofmeadow® Type III assembly. There are three inches of growth media over two inches of engineered drainage media. The five inch depth enhances the drought resistance of the green roof ecosystem.

My first impression was: "I can belive to find this diversity of plants on a 14 stories building in the most densely populated business district of Pittsburg."

People from Heintz's office have a direct view on it, that's why they maintain it twice a year (manual weeding).

My transect analysis tells me the true. More than 20 species lives here! Some of them were very attractive even if the majority of the plants's roof were still dormant. Let's see those wonderful Phlox Subulata, Potentilla Verna, Allium Tuberosum or Festuca Glauca. Incredible!


Here, Sedum species really cover the entire roof and the accent plants give it a colorful sensation. I didn't notice any invasion by one particular specie; It was a balanced competition.


But how it's possible to obtain these diversity?
One solution is probably the media. When I opened a part of it, I was surprise to see how the roots penetrate the layer to take water from the drainage layer. As you can see on the photo, they love that!


Finally, some insects like this nice ladybird were happy to live here.



Vive la biodiversité!