The 45,000 square foot green roof on the eighth floor of the Peco Building is the largest ever installed on an existing building in an urban area of Philadelphia.
43,000 square feet of this roof are drought resistant and comprise of 12 different species of Sedum plants. These Sedum are succulents and can survive the extreme heat. On this roof, they're low-growing and low-maintenance.
"We made a very definite decision to choose plants that were drought resistant or drought tolerant," said Liz Williamson of PECO.
All of these plants have fleshier leaves and a root system that helps retain moisture, which goes to show that they are built to take care of themselves.
Even during last summer's prolonged drought, this area wasn't watered. The plants did recede, but have since recovered, now filling the roof again this summer.
Ornamental grasses and perennials make up the other 2,000 square feet of the roof. They're all indigenous of Pennsylvania and are drought tolerant -- which means they do need water.
A drip irrigation system runs underneath and directly provides moisture into the soil and the plants without losing any water into the atmosphere.
The hope of this green roof is to decrease the amount of water used for the grasses and perennials as they grow and establish a hearty root system.
