Although the popularity of green roofs today leads to increasing the positive impacts for which they are often used -- namely reducing heat gain, reducing storm water runoff, increasing biodiversity in urban areas, and looking prettier than typical flat roofs -- this situation also means that green roofs become standardized, they become products, they lose creativity.
Architects can choose to cover their roofs with intensive or extensive systems, in trays, in planters, spread across the roof, most planted with a strain of low-maintenance sedum to reduce water needs and increase the likelihood of the vegetation lasting longer. Variety in design typically comes from the choice and combination of plantings and the form of the roof. While the former certainly falls in the realm of landscape design and the latter is a product of architectural design that may not take the green roof into consideration until after the form is decided upon, one wonders, where does the interaction of architecture and landscape takes place? Where does the creativity of the designer take the green roof into account as a progenitor of architectural design?
One answer, or rather a multiple of answers by one individual, comes from Terunobu Fujimori, an architectural historian in Japan who creates architecture that appears traditional but whose surfaces hint at the uniqueness of his buildings, what Thomas Daniell describes as "shaggy and bristling, humorous and grotesque, uncanny and vaguely obscene, and at times surreally beautiful." This last can easily be attributed to his handling of vegetation on roof surfaces.
[Grass House | image source]
The Grass House alternates bands of vegetation and stone shingles to integrate the two realms of landscape and architecture, while at the same time allowing each to maintain its uniqueness.
[Leek House | image source]
This intertwining of the natural and the manmade (for lack of a better term) finds another means of expression in the Leek House. Here the choice of plant influences the architectural solution: wood shingles are dotted by a grid of openings that allow the thin leaves of the leeks to rise towards the sun. It couldn't be any more different from the Grass House.
[Tsubaki Chateau | image source]
Lastly, the green roof of Tsubaki Chateau appears more in line with today's green roofs, minus the sharp pitch, the projecting spikes and, oh, that tree at the roof's peak. The sod-looking roof creates a highly visible green "cap" for the building, one literally capped by a tree in a symbolic gesture that, like Fujimori's ouevre, links tradition and idiosyncratic design.