The Washington Nationals' new baseball stadium opened the 2008 season with one. Vancouver's 2010 Winter Olympics will feature many more. And earlier this year Minneapolis decreed that the city's voluminous Target Center arena will have one too.
Suddenly, green roofs are sprouting across North America. Designed to curb air pollution, decrease energy expenses and reduce storm runoff, the environmentally friendly assemblies are adding a decidedly earthy element to urban skylines -- a sign that the green roof industry is rapidly coming into its own.
Particularly in cities, the rise of roof-topping grasses, succulents and other vegetation is fueling a boom for landscape architects, growers, builders and consultants in the know. As the roofs bloom in size and number, cities are weighing new incentives to developers and owners to install the admittedly costly growing medium and plant life as a long-term investment that could benefit both businesses and surrounding communities. And with a strengthening infrastructure to support them, designers are branching out in new directions.