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Sunday - June 12, 2011

From: Washington, DC
Region: Mid-Atlantic
Topic: Green Roofs
Title: plants for a green roof
Answered by: Guy Thompson


Dear Mr. Smarty Plants, We have a small, homemade green roof with a 4" medium on our sunroom, which faces south, however, a portion is partially shaded a Sweet Gum tree. Native Iris cristata, phlox subulata, & nodding onions are doing well & plan to add chives. The prickly pear suffered from snow sliding down from the main roof. Alpine sedems thrive, but we are trying to go native & provide wildlife benefits. A mourning dove pair uses the roof with their fledglings, which kept them safe from cats. However, they are vulnerable to crows and hawks, so we would like to add some cover. How about Prairie Rose? Is it native to DC? Any other natives to suggest, cover or otherwise? Any evergreens?


Finding successful green roof plants is still an work in progress.  What works at one site may fail just down the street under different conditions.  Mr. Smarty Plants recommends that you try a number of plant species, hoping that a few of them thrive.  The Lady Bird Johnson Wildflower Center maintains a fairly brief list of plants that have proved themselves in warm climates. Other sources are available on the Internet, including this one listing some taller plants that should provide shelter for your doves.  Among the taller perennial plants are Bignonia capreolata (Crossvine),Echinacea purpurea (Eastern purple coneflower)Schizachyrium scoparium (Little bluestem)Salvia greggii (Autumn sage)Rudbeckia hirta (Black-eyed susan), and Coreopsis lanceolata (Lanceleaf coreopsis).  Most of these also provide food for wildlife.

One species of Prairie Rose, Rosa setigera (Climbing prairie rose), would provide hips liked by wildlife, and another,Rosa arkansana (Prairie rose) has smaller fruit.  Whether these would thrive in 4" of medium is something you will have to test.

A list of native plant suppliers can be found at this website.


From the Image Gallery

Bignonia capreolata

Little bluestem
Schizachyrium scoparium

Black-eyed susan
Rudbeckia hirta

Eastern purple coneflower
Echinacea purpurea

Lanceleaf coreopsis
Coreopsis lanceolata

Prairie rose
Rosa arkansana

Autumn sage
Salvia greggii

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