If you’ve walked along roadsides, trails, or riverbanks in Vermont lately, you may have noticed tall plants with large clusters of white flowers towering overhead. While impressive in size and appearance, not all of these plants are created equal. Two species in particular—cow parsnip (Heracleum maximum) and giant hogweed (Heracleum mantegazzianum)—often get mistaken for one another.
Cow parsnip is a native plant found throughout Vermont. It typically grows between 4 and 8 feet tall and features broad, lobed leaves and solid green stems that may be slightly hairy. Its white flower clusters form a relatively flat-topped shape about 8–12 inches across. While its size can be striking, cow parsnip is a beneficial part of the local ecosystem, supporting pollinators and other wildlife. Contact with this plant may cause a rash or burn, but the plant tissue must be broken to come in contact with the toxic sap.
Giant hogweed is an invasive plant that can grow up to 14 feet tall and has umbrella-shaped flower heads that can span over 2 feet across. The most notable distinguishing feature is its thick, hollow stem, which has distinct purple blotches and coarse white hairs. Contact with this plant causes severe rashes, burns, and blistering; just brushing up against the plant can transfer the toxic sap onto yourself or gear.
Giant hogweed is not widely established in Vermont, making it important to find and report it early. If you think you've spotted it, avoid touching the plant and report it here.
Looking for more photos? Check out the New York Department of Environmental Conservation Giant Hogweed page.