Cedric Williams Jr. zipped between the trees, yanking up one slim green stem after another in a whirl of activity, until he had collected a bunch.
He ran down the sun-dappled hill in Patapsco Valley State Park, stuffed the plants into a white trash bag, then resumed his frenzied pace of pulling.
"Cedric, don't pull so violent - make sure you're getting the roots," his father, Cedric Williams Sr. of Woodstock, called after him.
"I'm getting the roots," the 11-year-old replied.
The Williams men - and dozens of others spread throughout the Avalon and Glen Artney areas of the park yesterday afternoon - had good reason to be thorough: They were hunting down and uprooting the so-called "villain of the valley," otherwise known as garlic mustard.
In its ninth year, the Garlic Mustard Challenge draws people from throughout the region to scour park woods for a lanky plant with broad leaves and tiny, white-petalled flowers. Named for the garlicky smell it releases when its leaves are crushed, the invasive species is a European transplant that tends to crowd out local species.
The challenge came out of an effort to "educate people about the environment," said John Slater, vice president of Friends of the Patapsco Valley and Heritage Greenway Inc., co-sponsor of the annual event.
Over the past eight years, contest participants have uprooted more than 8,750 pounds of the herb, said Betsy McMillion, the challenge coordinator.
"We're never going to fully stop it," Slater said, describing the myriad seeds that eventually explode out of the plant, giving rise to another generation.
But armed with garden gloves, white trash bags and a competitive spirit, yesterday's participants worked toward halting the biennial herb's progress, striving to pull up a ton - as in 2,000 pounds - of garlic mustard.
"It's pushing the other plants out of the park," Lisa Wingate, a Friends board member, explained to Charlie Stratton, 8, who was being briefed on his mission for the afternoon.
Charlie had come with his mother, Barbara, for the first time. Barbara Stratton said she has been reading up on the herb's possibilities on a Web site dedicated to "edible wild things" and aimed to pick until she had "enough to eat." Having already tried dandelions, she said, she was hoping to do more.
"I figured this was a good start," Stratton said.
As the two hours of yanking and pulling drew to a close, teams made their way back to the pavilion. They were greeted by a couple of owls - courtesy of the park service's Scales and Tales program - and several other environmental exhibits, including a display on worm composting, examples of other invasive species and state park trivia.
Several adventurous participants had stepped up to a cooking challenge, inventing recipes using garlic mustard. Their creations - garlic mustard pumpkin bread, garlic mustard pesto pasta salad and garlic mustard oatmeal among them - sat on a table, waiting to be judged.
Live music wafted through the air along with smoke from a fire where children cooked marshmallows for (garlic mustard-free) s'mores. Some set out to search for items in a scavenger hunt while others tested their skills at blowing bubble gum.
As they played, the pounds of herb were tallied, eventually totaling more than 2,075 pounds of garlic mustard uprooted from moist park soil.
For her part, Stratton drove home having met her personal goal, with bags of garlic mustard destined for her kitchen, where she'd be taking up her next challenge.