saw this article in The Coloradoan. http://greenroof.agsci.colostate.edu/ i don't care how hardy a plant is on a 110 degree roof it is going to need water. I think a great business opportunity is the green roof removal business. Here are the plant choices. EPA GREEN ROOF PLANTING PLAN The green roof will have 4 deep modules randomly planted at 8 on center with the following mix of several species of Sedum: *Sedum cauticola 'Lidakense' - blue/gray foliage, pink flower, bloom August-Sept, height 4 and 6 inches *Sedum floriferum 'Weihenstaphaner Gold' - green foliage, orange/yellow flower, bloom July- August, height 4" *Sedum hybridum 'Immergrauch' - green foliage, yellow flower, bloom July-August, height 6" *Sedum kamtschaticum - green foliage, yellow flower, bloom June-July, height 6" *Sedum reflexum - blue foliage, yellow flower, bloom June-July, height 6" *Sedum sexangular - green foliage, yellow flower, bloom June-July, height 4" *Sedum spurium 'Fuldaglut' - Red foliage, Red flower, bloom Fall, height 6" *Sedum ternatum - Dark green foliage, White flower, bloom May-June, height 2" These species were chosen by the green roof subcontractor, Green Grid, as selections that are well-suited to the Denver climate in terms of drought tolerance and cold hardiness. This selection is per the intentions that the green roof be a dry land tapestry that will change its appearance seasonally, looking very dormant and lifeless at times.