The best species to plant in rain gardens and stormwater swales

A rain garden is basically a planted basin, usually oval or kidney-shaped with well-amended soil in the bottom, that’s located in a low spot at least 10 feet from the house where it can collect rainwater from downspouts. The plants’ roots filter and cleanse this runoff of pollutants before it percolates into the soil, replenishing groundwater; they also slow the flow of stormwater into sewers, which can help prevent overflows from entering waterways. If you can’t plan for a natural wetland on your property, this is the next best thing. Bonus: some municipalities, like the City of Portland, will install a rain garden —basin, plants, and all—completely free of charge.