It’s easy being green: New research supports green roof advancement in the U.S.

Chicago Botanic Garden's Green Roof Garden atop the Daniel F. and Ada L. Rice Plant Conservation Center. (C) Chicago Botanic Garden

Richard Hawke, Associate Scientist and Plant Evaluation Manager, Chicago Botanic Garden

Imagine looking down on a major cityscape and seeing a sea of lush greens dotted with vibrant blues, yellows and Mother Nature’s other favorite hues. Normally, that type of scenery can only be found in the Midwest, over expansive prairies or western plains. However, in the future, metropolises could become “Emerald Cities,” distinguished by the green roofs crowning their skyscrapers and buildings.

Green roofs, also known as living roofs, are partially or completely covered with vegetation and have numerous social, economic and environmental benefits – from lessening storm water runoff and filtering pollutants, to adding aesthetic appeal, reducing energy costs, and more. However, to fully reap the benefits of green roofs, the plants must be right.

Chicago Botanic Garden’s Green Roof Garden atop the Daniel F. and Ada L. Rice Plant Conservation Center. (C) Chicago Botanic Garden

As such, in 2009 I began research atop the green roof of the Chicago Botanic Garden’s Daniel F. and Ada L. Rice Plant Conservation Science Center. The goal of my research was to help fill the significant void that exists in understanding green roofs. Through the various plant trials that my team and I conducted on the roof, I hoped to increase the scientific and gardening communities’ knowledge about the best plants for green roof culture.

Over the course of five years, a diverse group of 216 herbaceous and woody taxa were evaluated in the extensive (growing depth of three to six inches) to semi-intensive (growing depth of six to eight inches) green roof garden. My team and I watched, documented and analyzed data collected from the green roof, keeping five criteria top of mind when considering each plant’s sustainability, including adaptability, pests/diseases, winter hardiness, non-weediness and ornamental beauty.

Throughout the study I was surprised by —> Read More