Kuma Kengo’s new design features cool roof gardens

Famed architect Kuma Kengo’s new building, Tamagawa Takashimaya S+C Marronier Court, features cool roof gardens that jut out over the sides of the building on four levels. I am curious what the plants are, and how it will look as they cover the triangular frames. More photos on Designboom.
Yes, this is cool. I see this on my way of bicycle road training.