One day when we could not go onto the roof due to weather, we each researched succulents that we thought would work well on the succulent/xeric roof garden. It was an educational experience, as I really did not know much about succulents beforehand. We were given a list of plants to look up to research their hardiness. These plants included:
Sedum reflexum f. cristatum
Sedum moranense subsp. grandiflorum
Sedum kamtschaticum subsp. ellacombianum
Delosperma ‘Mesa Verde’
In addition to these plants, we were to suggest additional succulents to add to the list of potential species that would grow on the roof. Everyone suggested a variety of interesting plants to look up. I suggested Graptosedum ‘Vera Higgins,’ Sedum palmeri, and Sedum potosinum based on their known ability to grow within Central and South Texas.
On a green roof, we learned that there are a variety of different factors that affect the hardiness of plants. The main opposing climatic conditions consist of high heat and humidity during the summer and freezing temperatures in the winter. Previous green roof trials failed to meet an occasional freeze into the lower temperatures. With this in mind, it is important to research plants that can withstand the lower temperatures at least moderately, so that they will not die every few years when the temperature gets that low.
Ultimately, we planted a Delosperma species as well as several other sedums as mentioned in the previous posts. Researching plant species ‘extends the horizons’ and challenges the perception on what a truly defines a green roof. As research continues, more knowledge on the durability of these plants on will increase the variety and frequency of efficient greenroofs in Texas.