I've been reading up on rain gardens and green roofs lately. The rainy season isn't far off for us here in Tallahassee, and (if the drought ends this year) we're in for our daily flooding. Rain gardens and green roofs have a lot of benefits like preventing soil erosion, keeping stormwater runoff from entering waterways, and filtering CO2 from the atmosphere. Green roofs are also very efficient insulation, and double or triple the roof's lifespan.
We're talking about putting in a rain garden this year to catch some of the runoff from our driveway, roof and patio, and to cut down on the amount of mowing we do. If I were building a new home, I'd seriously consider a green roof, but I don't think it's an attractive option for a retrofit.
Does anybody have any experience with either of these?