HAMPTON ROADS — Although it may sound like a monster from a classic B-movie, giant hogweed is very real and it’s also more than a little bit dangerous.
And it’s probably already well on its way to Hampton Roads.
Giant hogweed is a long-lived perennial plant that produces a clear, watery sap, which when it comes into contact with human skin can cause blisters and serious skin inflammation.
It’s a Tier I Noxious Weed in the State of Virginia and the blisters it causes can last a few months or even a few years.
“This weed is not something to play around with,” said Andrea Davis, Virginia Cooperative Extension Horticulture agent in Virginia Beach. “It does look similar to some other common weeds, but if you suspect it could be giant hogweed, protect yourself first before any further investigation.”
Davis said that protective gear should be used before coming into contact with giant hogweed. It’s also reportable to the Virginia Department of Agriculture and Consumer Services.
If a person comes into contact with the plant and its sap, it is recommended they wash the affected area thoroughly with soap and water as soon as possible and keep the exposed area away from sunlight for at least 48 hours.
If a reaction occurs, topical steroids applied early can reduce its severity and ease discomfort. If sap gets into the eyes, rinse them with water, wear sunglasses, and seek immediate medical care.
Since the affected area may be sensitive to sunlight for a few years, it may be necessary to apply sunblock or to keep the affected area covered when going out in the sun.
“Giant hogweed reproduces by seed and spreads by seed dispersal, which can be aided by wind, water, people, and animals,” Davis said.
Once in the water seeds can float and be carried by the current for up to three days.
Eliminating the seed head before the seeds are dispersed is the key to stopping its spread, she said. But since it often grows in areas that are unmanaged, that’s unlikely to happen and the spread will continue.
Skin reactions are different, depending on a person’s sensitivity. When the sap contacts skin and is exposed to sunlight, specifically ultraviolet light, it can cause phytophotodermatitis. The toxic furanocoumarins are present in all parts of the plant: The lower parts of the hollow stems and petioles may be partly filled with sap, and the hollow hairs on the plant also contain sap.
“Unless instructed otherwise by VDACS, observers of this weed should move to controlling it after reporting it,” Davis said.
Control of giant hogweed can be done manually or with herbicides.
“Weed eating is okay as long as you start when plants are small and continue mowing throughout the season,” Davis said. “Weed eating or mowing should not be done to plants with a flower or seed head to avoid spreading seed.”
Weed eating can splatter the sap that is harmful to humans.
For information on safely handling and eliminating giant hogweed, which requires more than simply cutting it down, Davis suggests reading “Control of Giant Hogweed” from the New York Department of Environmental Conservation.