The Department of Horticulture and Landscape Architecture at Colorado State has indentified five particular species of plant that work well in semi-arid climates for green roofs.
Energy Daily reports that "Previous research on species that can survive and thrive on extensive green roofs has shown that succulents outperform most non-succulents."
Blue grama and hardy ice plant weathered the test best, outperforming other succulents.
The study is being conducted on the roof of the Colorado headquarters for the Environmental Protection Agency, a LEED-certified office building.
From the EPA's website:
"While installing green roofs has been gaining in popularity in temperate areas marked by relatively ample rainfall such as Europe (green roofs are particularly popular in Germany) and the Northeastern U.S., developers, architects, and building managers have much less experience installing them in places with low rainfall and the solar extremes presented by high altitudes. EPA's green roof is the first of its kind in the state of Colorado."
FULL STORY: Five Standout Species for Extensive Green Roofs

Rethinking Redlining
For decades we have blamed 100-year-old maps for the patterns of spatial racial inequity that persist in American cities today. An esteemed researcher says: we’ve got it all wrong.

Planetizen Federal Action Tracker
A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

Walmart Announces Nationwide EV Charging Network
The company plans to install electric car chargers at most of its stores by 2030.

Knoxville Dedicates $1M to New Greenway
The proposed greenway would run along North Broadway and connect to 125 miles of existing trails.

Philadelphia Launches ‘Speed Slots’ Traffic Calming Pilot
The project focuses on a 1.4-mile stretch of Lincoln Drive where cars frequently drive above the posted speed limit.

NYC Delivery ‘Microhubs’ Aim to Cut Down on Truck Pollution
The hubs are designed to provide parking for large delivery trucks, which can pass on their cargo to bikes or other zero-emission vehicles.
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