Using succulents as green-roof plants Q: We e interested in putting succulents on the roof of a small storage building in Southern CA. How would you go about it?
Green roofs are primarily a cool-climate phenomenon and the succulents used for them are mainly sedums and sempervivums. In the dry, hot Southwest, plants on rooftops bake in summer, there isn’t enough rainfall to keep them going, and what the heat doesn’t kill, winter frosts may. The only flora that might have a chance would be desert plants. You might use multiples of dwarf agaves or barrel cacti (which from a distance would provide a marvelously nubby look). As for construction, your green roof will need a moisture barrier to protect the structure—which also may need to be reinforced to hold the additional weight—and perhaps some means of irrigation (such as drip). There’s an excellent book by Ed Snodgrass about constructing green roofs, and info online as well.
