The EPA's Rain Garden

Last week in Washington, on Tuesday, in the rain, we sloshed by the Environmental Protection Agency's Washington office. They have a rain garden between building and sidewalk! Of course it's the government that brought you "Advanced Interrogation Techniques" so they refer to it as a "Bioretention Cell." Sounds like a cell of bio-terrorists.

The rain garden comes complete with interpretive signage.

The purpose is to have the garden act like a sponge to absorb storm water runoff. Underneath the garden are a drainage pipe and bed of gravel topped with porous soil and mulch. The plantings are both water and drought-tolerant (??), and keep soil from compaction. All we saw was this great display of tulips, trees, shrub and grass. I'd love to see what other plants–the perennials–they have for this garden. And I'd like to see them when it's not raining.


  1. Very cool - rain gardens and bioswales have become a hot topic out here in California as well. There is a church nearby me that has installed bioswales instead of traditional drainage in the parking lot, with the intention that the plants will filter out all the polluted run off that comes from the cars, etc.

    FYI, there are plants that can handle both bog and drought conditions, but it's news to me that a Japanese maple is one of them! Could be different in your neck of the woods where they get all the humidity they crave.

  2. Can't think of a better plant than one from Holland if you're having to deal with the control of water... Is that a Sandcherry in the middle? It would be interesting to see what they come up with in the summer.

  3. SusanGardenChick,
    I don't remember, or can even really tell, beyond a shadow of a doubt, if the red-leafed trees are Japanese maples. I know that here in Buffalo, if every business and resident had a rain garden (bioswale sounds WAY cooler) it would relieve stress on our partially-Civil-War-era storm water/waste-water system.

    Come to think of it, if memory serves that just may be the tree in the photo.

  4. Beautiful. I too would be interested to see how it looks in high summer.

  5. It is actually us engineers who coined the phrase bioretention. they are engineered retention cells deliberately planted. vs the ones you notice around you with weeds in them.


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