Roof Research Site Plant Performance Evaluation This study site provides actual roof conditions to conduct research on plant selection, growth media formulation, and fertilization options. Various species are being evaluated for drought tolerance, winter interest, sunlight requirements, and other considerations that affect green roof suitability. Additionally, various growth media formulations, including expanded clay, expanded slate, lava rock, and pumice, are being evaluated for rooftop suitability. The research team is also studying the performance of several fertilizers and the possible leaching associated with each strategy.  The goal of this research is to establish tolerance threshholds for stress and to identify plant species suitable for green roof propagation. To recommend a plant species for evaluation, e-mail the research team at wretzla@siue.edu. Sedum species evaluated: Weihenstephaner Gold Album Mural Immergrausch Spurium "Dragons Blood" Sexsangulare Headline Growth Media & Fertilizer Evaluation 108 Green Roof Blocks planted September 20, 2005 The St. Louis region experienced the fifth worst drought on record during the months of July and August 2005. Some green roof plants experienced significant injury while other green roof plants seemed to weather the drought fine. Once the disappointment about the dead plants subsided we realized we were presented with a golden research opportunity. We noted that there were some commonalities among the affected plants; growth media, plant species, fertilizer. To gain a better understanding of the how the green roof variables effect drought tolerance we set up a replicated experiment using 108 Green Roof Blocks to evaluate three plant species, four growth media, and three fertilizing strategies. The plants are being monitored to determine growth rate and overall health. Some modules have been equipped with temperature sensors to study how the varying components effect the roof surface temperatures.