Don’t all gardens collect rain? Of course, but these particular gardens collect parking lot runoff and allow it to settle into the planted swales. It’s a great way to remove our rainwater from hard surfaces instead of allowing it into the storm sewer and flooding and polluting our streams and wetlands. The parking lots have no curbs so all water runs to the swale. The plants are mostly native and must be able to withstand drought since they are planted in 6 inches of sandy loam over 2 feet of sand! Further, they must also be able to withstand short term flooding during heavy storms.