Plants
LiveRoof Component - Plants
Plant Basics
Not all green roofs are created equal, or are equally green. The rooftop is an unforgiving environment for plants. Our knowledge of your local conditions is essential for figuring out what plants are best for your project. That’s why we customize our plant and grass selections for your specific area, unlike other vendors who recommend a sedum roof consisting of exotic species that may have performed well in other states but are known to do poorly in Texas.
Recommended Plants
LiveRoof Texas approaches each green roof project from a horticultural point of view. We see the rooftop environment as a biological system, and understand what it takes to produce a horticulturally sound, sustainable system designed so plants will flourish.
We provide regional pallete plant mixes with plenty of native xeric groundcovers, several ice plants, succulent perennials with good colors, and short-stature grasses. Please see our plant list page for more details on what plants will work best for you.
Why Don't Sedums work in Texas?
Sedums are succulent, water-holding plants that have a special type of metabolism called Crassulacean Acid Metabolism, CAM
for short. CAM plants are unique in that under drought conditions their stomates (leaf pores) are open at night rather than during
the day (as is the case with most plants). This allows CAM plants to be much more efficient with water conservation than non-CAM
plants. So why don’t they work on roofs in Texas?
Most sedums come from dry temperate climates. They do very well during the cooler months in Texas when the high temperatures and humidity are not around. But when those summer afternoon temperatures reach between 90 F to 100+ F and the air water vapor is high, sedums struggle to keep their cover and then invasive species can take over. But it is not the high heat and humidity, itself, that causes sedums so many problems. These two factors simply provide the perfect environment for the real sedum killer, Southern Blight Fungus, also known as ‘crown rot’ and ‘white mold’, to thrive. This fungus is practically impossible to keep at bay once the hot, humid summer months arrive and it will decimate even a well established roof of sedums.
An extensive green roof study was conducted at the University of Texas at Arlington by associate professor and landscape architect, David Hopman, ASLA, in 2008. Part of this study included the testing of five sedum plants. The results of the sedums testing produced two major issues. First, the sedums required watering in order for them to not go dormant or die in the summer. The second, and more concerning problem, was that during hot rainy weather some sedums began to rot.
The study concluded that the use of sedums on green roofs in Texas should be avoided due to the two limitations and the non-regional origins of sedums.