This weekend I discovered an ecological gem right in downtown Durham. I have walked by the parking garage green roof maybe a thousand times, situated as it is between Foster Street and Morris Street, but I have never really seen it.
A friend and I were walking back from the Durham Farmers’ Market when the bright colors of the green roof’s flowers caught both our attention. Our curiosity piqued, we climbed the stairs and entered the grassland oasis.
Green roofs have fascinated me lately. Taking advantage of abundant sunlight on city roofs, they insulate buildings against the heat of the summer and cold of the winter, reducing cooling and heating costs. They even change the albedo of the buildings, which are often dark and thus absorb the sun’s rays. Additionally, when it rains the vegetation can absorb and clean stormwater, reducing pollution and preventing harmful runoff from eventually entering nearby waterways or cleaning facilities.
While I appreciate these effects, what I really love about green roofs are their capacity to support native plants and wildlife species. The majority of the parking garage roof is covered with Pink Muhly Grass, according to Hoffman Nursery, while bright red and yellow flowers bloom next to the walkway. The plant beds seemed alive there were so many pollinators, including the very bees that have been in the news for their declining population numbers. What an amazing use of space, especially compared with the cold, hard concrete or brick of many city roofs.
The wildlife definitely appreciate the green roof, and I did too. Though we were only a few stories up, the urban noise was reduced substantially, replaced by the buzzing of the bees and a light breeze blowing through the grasses. We were elevated enough to see an interesting cityscape, and I noticed other buildings and new features of Downtown Durham. I know that if I worked nearby, this parking garage roof would be a great place to eat lunch in nice weather.
It’s true that green roofs are not necessarily easy to begin or maintain. A roof gardener must have an understanding not only of gardening, but also take into account the weight of the garden and hydrology, so that the roof itself does not cave in or cause damaging leaks. Still, I am excited to learn more about the process because the benefits so outweigh any of the start-up costs. I’m imagining Durham with an additional plant layer on every roof, reducing negative urban externalities while contributing positively to local species. Why not?