Giant hogweed, the towering plant with umbrella-like white flowers, may look striking along a roadside or stream bank, but getting too close can have painful consequences.
As giant hogweed reaches peak growing season, the New York State Department of Environmental Conservation is reminding residents to recognize the invasive plant, avoid touching it and report suspected sightings. The plant’s sap contains chemicals that, when exposed to sunlight, can cause severe blistering burns and permanent scarring.
“It’s definitely a good thing to learn how to identify and learn to avoid,” said Daniel Waldhorn, an invasive species specialist with DEC’s Division of Lands and Forests. “If you see any, definitely reach out to us and we can be of assistance.”
Giant hogweed is a member of the carrot family that can grow between 8 and 15 feet tall. Its flower clusters can reach more than 2 feet across, and its thick stems are marked with dark purple blotches and coarse white hairs.
The danger comes from the plant’s sap.
Waldhorn said chemicals in the sap react with sunlight after coming into contact with skin, damaging cells and causing severe rashes, blistering and peeling skin. Because sunlight is part of the reaction, he said anyone who suspects they’ve been exposed should immediately wash the area and stay out of direct sunlight.
“If you do get exposed to giant hogweed and some of its relatives, it’s a very good idea to wash off and go indoors,” he said. “Even if you are exposed, going indoors and avoiding direct sunlight can help you avoid a nasty rash.”
He also recommends seeking medical attention if a reaction develops.
Although giant hogweed is distinctive once people know what to look for, Walthorn said it’s often confused with other large flowering plants.
The most recognizable feature is its broad, umbrella-shaped white flower head, accompanied by several smaller flower clusters. The plant also has large, deeply serrated leaves and a thick stem with purple blotches and coarse hairs.
Some harmless plants, including elderberry and Queen Anne’s lace, are commonly mistaken for giant hogweed. But Waldhorn said people should also be aware of wild parsnip, another invasive species whose sap can cause similar skin burns. Unlike giant hogweed, wild parsnip is smaller and produces yellow flowers.
In New York, giant hogweed is found primarily in the central and western parts of the state, often along streams, farm fields and roadsides. Because its seeds are relatively large, the plant doesn’t spread far on its own. Instead, seeds are often carried downstream by waterways or moved by farm and roadside mowing equipment.
If homeowners discover giant hogweed on their property, Waldhorn recommends contacting DEC before attempting removal.
An individual giant hogweed plant can produce up to 20,000 seeds, Waldhorn said, and those seeds may continue germinating for five to nine years. As a result, DEC and its partners revisit treatment sites over multiple growing seasons to prevent new plants from reaching maturity and producing more seed.
Beyond giant hogweed, DEC is also monitoring other invasive plants, including wild parsnip and kudzu, the aggressive vine that has begun spreading into parts of southern New York, Long Island and New York City.
For Waldhorn, public participation remains central to the state’s efforts.
The giant hogweed program began in 2008 with roughly 300 known sites. Today, DEC tracks about 3,000 locations — most identified through reports from residents.
People who suspect they’ve found giant hogweed can contact DEC’s information line at 845-256-3111 or email photographs to ghogweed@dec.ny.gov. General invasive plant questions can be sent to invasiveplants@dec.ny.gov.
Residents can also report invasive species through the New York iMapInvasives database, which Walthorn said helps DEC and partner organizations identify new infestations and prioritize management efforts.
“The data will be used in turn by the DEC and other organizations to drive management practices,” he said.
Image Credit: NYDEC