An invasive giant hogweed plant in Virginia. (Credit: Virginia Tech)

Researchers at Virginia Tech recently identified a towering invasive plant that has sprouted in Virginia for the first time: The giant hogweed, Heracleum mantegazzianum. It's one of those wild things that should come with a Do Not Touch sign — its sap can cause painful burns. Hogweed has been a problem plant in Pennsylvania and New York but had not been seen so far south in the U.S., until now, as The Post reported this week.

Giant hogweed grows best in the borders between forests and open areas, particularly along roads and streams. River currents spread hogweed if the seeds fall into water. But human hands have, historically, been the most significant contributors to the plant's spread. (One of the plants found in a Virginia, it turned out, was grown as a decoration.)

Horticulturists looking for the next ornamental curiosity brought the plant to England in 1817, where it escaped the Royal Botanic Gardens and flourished in the wild. By the mid-1900s, scientists recognized the toxicity of giant hogweed sap, but the weed had already taken root across the Atlantic.

Hogweed sap requires a partner in crime — photons. Activated sap on skin produces are blisters, like a very aggressive sunburn. Years ago, I spoke with a member of a New York crew tasked with destroying the plants. She'd dug up a patch of hogweed on a rainy day in 2010, unaware her suit was compromised. The skin on her leg turned bright red.

Within a week, the back of her calf began to bubble. The state's hogweed control program uses photos (they're graphic) of her wounds in an informational brochure.

But she was back in the field months later. As if to prove the toxin's weak spot — darkness — she plucked a seed off the top of a plant, popped it into her mouth and chewed. “It would taste good on chicken,” she said. She spat it out, but if she hadn't,  "it wouldn't have bothered me, cause the sun doesn't shine down there.”

— Ben