Paradise Unpaved: Adkins Arboretum’s Parking Lot Becomes an Extension of its Gardens

Insects flock to the plants in Adkins Arboretum’s parking lot on a fall day. Photo credit: Nicky Lehming

The project removed a total of 4,987 square feet of asphalt, according to the arboretum. And though no agency monitors the water at the arboretum to detect how much nitrogen and phosphorus the garden is keeping out of Tuckahoe Creek, Buehl said the estimated load reductions per year are approximately 10.3 pounds of nitrogen, 1.1 pounds of phosphorus, and 660 pounds of suspended sediment. It may not be as substantial as other projects, Buehl said, but every pound helps, especially in a location so close to the creek. Excess nitrogen and phosphorus that flow into creeks can cause algae blooms that block light needed by underwater grasses to thrive. The numbers on this project are not comparable to, say, upgrading a large sewage treatment plant, but Bay restoration depends on many little projects to make overall progress, Buehl said.

“We’ve reached the point in Bay restoration where everything helps and everyone needs to do their part,” he said.

They call the project Parking Lot Alive! and the description seems apt. On a recent autumn visit, butterflies flitted about on fragrant aster, blue mist, and milkweed blooms, while kingfishers, pileated woodpeckers, and herons could be spotted gliding by. Besides the seven planted gardens, the parking lot now features sediment control devices with sandstone or gravel on the bottom to help filter the water as well as an underground conduit to direct stormwater flows to the gardens from the lot in times of heavy rains.

“Before, it was pretty clearly barren for an arboretum, and now, it is so alive,” Tiernan said. “Now, when you come in, you totally know that you are somewhere special.”

The Adkins Arboretum parking lot lost only a handful of spaces in their parking lot renovation, but they gained beautiful gardens that help absorb runoff from storms and protect the water quality of tributaries to the Choptank River. Photo credit: Nicky Lehming

Buehl wants the aboretum to be a demonstration site for other parking lot projects. Often, he says, people don’t think they can do the work or find the money. In this case, Unity Landscape was able to construct the project, after design work from Campion Hruby Landscape Architects and DesignGreenLLC. The design incorporated Adkins’ needs, including a turning radius for buses and accessible parking spaces near their facilities.

The arboretum estimates it has 18,000 visitors a year. Visitors had commented on the new look, but the arboretum got its big test in the late spring, when Tiernan nominated it as a site for the American Public Garden Association’s field trips from its annual conference in Washington, D.C. It was accepted.  The response was overwhelming as more than 60 attendees visited. “That was like putting us on a national map,” she said.

Tiernan credits Buehl with putting it all together, and said others in the county looking to do such water quality improvement projects should reach out to Sea Grant Extension specialists to find sources for funding, expertise, and design help.

“This was something where there was an opportunity,” she said, “and I think there will be more and more of those.”

If they do, perhaps more parking lots will show signs of life as they help protect water.

Photo, top left: Maryland Sea Grant Extension Specialist Eric Buehl examines new growth near the parking lot of Adkins Arboretum with Kathy Thornton, the arboretum’s land steward. The greening of the parking lot removed nearly 5,000 square feet of asphalt. Photo credit, Nicky Lehming