Photograph by Wolfgang Kaehler, LightRocket, Getty Images
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Hogweed grows among wildflowers in Washington state. The plant has been spotted in the Pacific Northwest and Northeast.

Photograph by Wolfgang Kaehler, LightRocket, Getty Images

What Is Hogweed, the Invading Plant That Burns and Blinds?

The striking plant was brought to North America to decorate gardens and arboretums, but now officials are working to wipe it out.

If you see it growing in your garden, don't touch it.

The 15-foot-tall invasive plant locally known as hogweed (Heracleum mantagazzianum) was recently spotted for the first time in Virginia. Experts and locals are on high alert because the notorious plant produces a dangerous, clear sap that can cause third-degree burns, severe blisters, and permanent blindness.

The plant has previously been identified in more northern regions in Canada, the Pacific Northwest, and the northeastern U.S., and now officials in Virginia are monitoring the region to see if it takes hold there, too.

How Did It Spread?

The plant's dangers didn't stop enthusiastic gardeners from bringing it to North America over a century ago. Before it was classified as a noxious weed in several states, it was cultivated as an ornamental garden plant. Native to regions bordering the Black Sea like Russia and Georgia, hogweed spread to the rest of Europe and North America in the 19th and 20th centuries when it was transported by collectors entranced by its unique beauty.

“It really is a spectacular plant. It's very Dr. Seuss-ian,” says Kevin Heffernan, a stewardship biologist with Virginia's Department of Conservation and Research.

He speculates the plant's allure is how it got to Virginia in the first place.

The plant was found in a home garden kept by hobby gardeners. Experts think it may have been growing for the past 40 years when it was first planted by the home's original owners. It was the the current owners who began to suspect the notorious weed was in their own backyard and sent photos to horticulturists at Virginia Tech, who confirmed the species. Forty years ago, buying and planting hogweed was legal, but today, Virginia classifies it as a noxious weed, meaning it's regulated by the state and can't be bought or sold.

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As a precaution, the weed was uprooted and removed. Other Virginia hogweed sightings have been reported but not yet confirmed.

“We're fairly confident it hasn't spread. If it had been found in the wild, alarm bells would be going off,” says Heffernan.

That's because in other regions where the plant has been found spreading, it causes serious, long-lasting harm.

Dangerous Contact

Just brushing against the plant won't lead to severe reactions. The plant's sap contains a chemical called furocoumarins, and when it mixes with sunlight, it causes a phototoxic reaction on skin called phytophotodermatitis. Permanent blindness can occur if the sap gets in your eyes.

Symptoms develop and worsen over several days before healing and leaving a lasting sensitivity to sunlight.

The plant can impact native species, too. The tall, hardy plant has a wide, upturned top that shades the forest beneath it. This can prevent native undergrowth from taking hold and leads to more unstable soil that erodes more easily during winter.

If you come into contact with hogweed sap, experts advice immediately washing the affected area, staying out of sunlight, and seeking medical attention.