What Should Grow in a Vacant Lot?

On a frigid day in the West Baltimore neighborhood Harlem Park, ecologist Chris Swan parks his pickup on a block where vacant lots outnumber houses. On the tailgate, he organizes envelopes of native wildflower seeds: Liatris squarrosa, Pycnanthemum muticum, Monarda bradburiana. For the next several hours, Swan, who teaches ecology at the University of Maryland, Baltimore County, will sprinkle the seeds over an acre and a half of scrubby land, lots that once held the neat brick rowhomes that still define much of Baltimore’s working-class housing stock.

Perennial wildflowers are best sown in fall or winter. “The seeds have to sit over the winter and kind of crack open,” Swan says. Trowel in hand, bundled in camouflage hunting gear against the cold, he’s an odd sight on this desolate street. His project is an oddity as well: He’s searching for the combination of native species that can thrive in the poor soil left behind after homes are demolished.