A Roof That'll Grow on You

Because of the shallow soil and harsh conditions on the roof, only especially tough plants, often those naturally adapted to rocky outcroppings, can thrive.

It's been fun experimenting with different plants -- on the first day of spring I glanced out the dormer window and noticed a crocus blooming on the roof. Bulbs work -- and so, quite surprisingly, did the sweet potato vine I planted near the edge. The dianthus was lovely for a few months, but it succumbed to the August drought. Portulaca, alyssum, sempervivum (hens and chickens), delosperma (ice plants) and many varieties of sedum have survived, and some have even thrived through the first year of our living roof.

The hardest part has been watering the roof -- impossible early in the construction when the plants were up before the hose bib was connected, and awkward even when water was available. Unfortunately, we lost a quite a few plants over the summer. Once established, they won't need to be nurtured as they have during this first year.

My husband and our children, 16 and 10, went to see "An Inconvenient Truth" this past summer, and as we were leaving the theater the kids discussed how proud they were that we have a green roof. In the face of daunting information about climate change, our children were informed and empowered.

Our little 300-square-foot patch of green won't stop global warming or even save the bay. But if many of us in the Washington area and across the nation plant green roofs, we will make a difference.

-- Nancy Striniste

Arlington

The writer is a landscape designer.

Her e-mail address isnstriniste@earlyspace.com.