Green roofs have worked well in Europe for decades and in the northeast United States since the 1990s, but the complex systems of balancing nature, architecture and smart energy usage have been absent in Texas due to the state’s dreadful amount of heat and dearth of water. So when it came to designing a green roof system that could withstand the state’s worst, two Texas Christian University graduates went west and looked down.

The catch is, however, that the plants used in green roof systems in other parts of the U.S. benefit from cooler temperatures and a fair amount of moisture. Applying those plants to Texas doesn’t work, so Williams and Jon Kinder decided to figure out what plants would, and how.