Giant Hogweed

Description

Warning: Public Health Hazard: Giant Hogweed contains a substance within its sap that makes the skin sensitive to ultra violet light. This can result in severe burns to the affected areas, producing swelling and severe, painful blistering. Large, watery blisters usually appear 15 to 20 hours after contact with the sap and sunlight. Contact between the skin and the sap of this species occurs either through brushing against the bristles on the stem (as with a stinging nettle) or breaking the stem/leaves. In the event of contact with the sap of this plant, the skin should be covered to reduce the exposure to sunlight and washed IMMEDIATELY and thoroughly with soap and water. Description: Giant hogweed is a member of the carrot and parsley family and is most distinguishable by its massive size, growing 15 to 20-feet tall. It closely resembles the native cow parsnip, which rarely exceeds six-feet, thus enabling differentiation. Stalks are hollow, have reddish-purple blotches and pustules with a single erect hair in the center. The flower head is a large umbrella-like inflorescence that can grow up to 2.5-feet in diameter. The leaves are three to five-feet wide, compound, and deeply-incised.

Habitat

Roadsides, other right-of-ways, vacant lots, streams, rivers, and riparian areas

Distribution

Northwest Oregon, Western Washington

Impacts

Health hazard to humans, crowds out native species, increases soil erosion along steam banks

Dispersal Methods

Water

Prevention

Look for giant hogweed in unmaintained urban areas and vacant lots, especially ravines and areas near know establishments. Dig up isolated plants and return the following year to check for new seedling or resprouted plants. Pay head to the health hazard when removing the plant. Carefully examine plants sold as cow parsnip, as giant hogweed is often misidentified as such.

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