The Hill Gardener

Up on the Roof Rooftop Gardens Greening our Neighborhoods

The garage top at 929 S St. NW in Shaw. Photo: DC Greenworks

Ever wonder what it would be like to escape to your own private urban oasis? Is it a place that has a stunning view and maybe a little breeze? A place where you feel like you are sitting on top of the world? Well, maybe that place has been there all along, up on your roof.

More and more folks are waking up to an idea that Europeans have been enjoying for years, and that is developing rooftops into green gardens and outdoor spaces.

It is estimated that at least 10% of all flat rooftops in Germany have a rooftop green space or garden, and the numbers are even higher in Sweden. In addition to the ecological benefits of rooftop gardens, they also allow people to enjoy nature even in crowded urban areas.

Rooftop gardens lower energy consumption and reduce urban heat and problems associated with heat stress. They can also help to improve storm water management if enough of them are implemented in an urban area.

There are really two schools of roof top gardens; those designed to be enjoyed as a living space or patio type area using containers; and those designed to be green providing a more environmental space that may be greening up the view and improving the air quality. Capitol Hill homes and businesses are catching the green wave and are beginning to adapt their rooftops in all kinds of exciting ways.

The Roof at Pierce School

Chris Swanson and Jeff Printz, owners and developers of the Pierce School at 14th and Maryland Avenue, NE, spend time on their rooftop oasis every day. Jeff says he starts his mornings with a cup of coffee in the garden as a mocking bird sings to him. The bird has adopted this gorgeous roof top garden as its home.

In addition to the bird life, this year Chris has installed a beehive on the roof, joining the estimated 100,000 backyard beekeepers across the United States. He said that he found the local Washington beekeeper association very helpful, and ordered his equipment online after attending some lectures. And, yes, he does own a white beekeepers suit. The bees the morning I visited were enjoying the gray cooler weather, and hadn’t taken off yet for pollen gathering. Sitting in the white box on the roof were 50,000 honeybees. Chris has so enjoyed having the addition of the beehive in his garden that he plans to add more in future years.

The roof top garden has spectacular views in whatever direction you look. The Capitol stands in one direction, RFK Stadium on another side, and at the front of the building the view is of the ever-developing H Street corridor, which is where Chris and Jeff’s business, Evolve Property Management,, has its offices. Chris says the garden is the perfect place for him to escape to when he needs a little peace and quiet. The garden is extremely quiet and you definitely escape the street sounds when you sink into one of the cushioned chairs or sofas that are scattered in several different seating areas. The space has hosted large dinner parties over the years and is equipped with a grill, sink, and refrigerator.

Lessons Learned

The recent heat wave had taken a bit of a toll on the garden, but Chris, like all good gardeners, has taken it in stride. Many of the plants are chosen for drought resistance because watering is a consistent issue, and the plants are also chosen for two other surprising reasons. With the garden so high up, wind is a serious concern. The other big factor is how much plant material a plant produces.

Some of the early plantings, simply didn’t survive, especially the trees that line the sides of the roof. Chris had experimented with an Oleander tree at a beach property and was impressed with its durability especially with very little attention having been provided. So, he replaced the failing trees with Oleanders, and they are thriving on the roof. Not surprising really, as the Oleander is subtropical and is known to survive the brutal California Santa Anna winds. “They do drop their leaves in the late fall”, Chris says, “but the trees really give us something every season from flowers to lovely green leaves in the summer.”

The plants have an automated irrigation line around the edges, which helps keep the entire plants watered daily even when the fellows are out of town. When asked if there were plants, he wished he could cultivate in this lush garden, Chris said that he wished he could get more vegetables to grow, but so far it has been too hot. The clusters of herbs do seem to be doing well.

The garden is a container garden, and investing in thermal containers has been another lesson learned. The ceramic containers are very heavy, and Chris laughs when he thinks about how hard they were to get up to the roof and to move around. Styrofoam containers didn’t hold up well in the wind. “While they are considerably more expensive, the thermal containers have really made a big difference in the garden,” said Chris.

Greening the Garage

Another business on H Street is DC Greenworks, a non-profit group whose mission is growing livable communities using living materials like green rooftops, water gardens and rain barrels. The group started in DC in 2000, and the current executive director, Peter Ensign, says that Greenworks has helped homeowners and businesses on Capitol Hill install many green roofs over the past few years.

The garage I toured with Peter was installed in the fall of 2009 in the Shaw neighborhood, and was 365 square feet, and captures about 6,080 gallons of water. The flat roof was accessed through a ladder in the garage and was built not to be a social space, but rather for the aesthetic value it provides for the owner and neighbors, and for ecological reasons. Peter says, “it is like creating your own micro-climate space and it can reduce the temperature in the surroundings by ten percent or more.”

The space is divided into three planting areas, with hardy grasses, succulent plants, and sedums planted that are drought tolerant. “Vegetables can be grown,” Peter said, “but it requires a little more attention, and if you don’t have easy access to the roof, probably not a good choice.” With irrigation lines, owners don’t have to go up and down often, and DC Greenworks often provides maintenance contracts with their installations.

Roof top green gardens are a relative new industry in the United States, and DC has been fortunate to be on the leading edge. DC Greenworks hopes to find more and better ways to drive down the cost and labor intensity of the projects, so that even more homeowners can take advantage of this important green trend.

What you need to consider in planning your own oasis?

Both Chris and Peter agree that you have to begin with a sound structural roof. In the case of Pierce School, the roof had caved in, so they were in the position of replacing the roof to hold their dream garden. Peter recommends that owners have a structural assessment done as the first step, and make the repairs identified.

The DC Department of Environment is a huge supporter of rooftop gardens, and provides a rebate of $5.00 per square inch of garden for DC residents. To learn more about the program, visit the website, green roofs. It will also walk you through the application process. DC Greenworks is happy to work with homeowners as well,

Once up and running, thinking through how the garden can be maintained, especially issues like watering and wind, as well as selecting appropriate plants that can tolerate heat and dry conditions is important. “It is definitely worth the effort,” says Chris and Jeff, “we have enjoyed our garden more than we ever thought we would. It is our special retreat.”

Rindy O’Brien is proud of her hill neighbors for their forward environmental efforts, for thoughts or comments contact her at

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