Have you heard of green roof technology? It's not just a Saint Patrick's Day thing. The greenin' o' the roof is a "fast-growing" trend. Here's why: In Europe, "green" rooftops are a common sight (filled with a wide range of low-maintenance plants -- often drought-resistant succulents from the popular and hearty "sedum" species). These rooftop blankets of natural green grow year-round in just a few inches of soil above a sealed waterproof membrane. Besides the aesthetic benefits, they provide better energy efficiency and rooftop water management by absorbing 60 percent of the rainwater that falls on them. Soon you'll be seeing a bit more o' the green here, too, as this "growing" trend starts to take hold. For more tips, visit our Web site at Onthehouse.com.