Giant Hogweed, Heracleum mantegazzianum, White Clay Creek State Park, Delaware

In Albums: plants White Clay

May 5th, 2006, by Alex Zorach

This photo shows giant hogweed also known as giant cow parsley, the plant Heracleum mantegazzianum, growing in White Clay Creek State Park, in Delaware. This plant was found along the main road on the west side of the road, in a wet area.

This plant is native to central Asia, but was planted elsewhere as an ornamental plant, and became an invasive plant. As it gets older, the plant grows taller than a person and sprouts giant umbrella-shaped flowers that closely resemble queen Anne's lace, leading some people to call this plant giant queen Anne's lace. When walking among these flowers, it feels almost as if you have been shrunk down to a tiny size.

Giant hogweed is potentially dangerous, as its sap contains chemicals which can dramatically increase photosensitivity. If exposed to this plant and then exposed to sun, people can incur dangerous sunburns in a very brief period of time. Exposure to the eyes can cause blindness. Because of these issues, this plant is illegal to import or move across state boundaries, although it is still unfortunately sometimes planted as a landscape plant.