Invasive Species Profiles
Giant Hogweed (Heracleum mantegazzianum)
Originates from Caucasus Mountains
- Monstrous height, reaching up to 5 m tall
- White flower heads reach up to 1.5 m in diameter, bloom in mid August
- Leaves are shiny and large, with coarse, jagged edges.
- Stalks have purple blotches, streaks or spots, and stiff bristly hairs.
- Usually found growing on agricultural lands, riverbanks, vacant lots, and along roadways.
Consequences of Invasion
- Outcompetes other plants and reduces suitable habitat for wildlife
- Produces copious seeds (100,000 seeds per plant)
- Dense taproot keeps producing leaves
- Direct impact on human health.
- The sap causes extreme dermatitis in the presence of sunlight.
- Contact can lead to welts, rashes, blistering, and scarring that can last up to 10 years after contact.
- If sap gets into the eyes, it can lead to temporary or permanent blindness.
Prescription for Control
- It is best to let a professional remove this plant for you
- If you are going to remove the plant yourself, always wear protective, waterproof clothing, gloves and safety goggles (WorkSafeBC has a great video here)
- Remove any flower heads into a plastic garbage bag
- Cut the root crown 3-4 inches below soil with a sharp spade.
- Continue to monitor the area for several years
- Once removed, plant native or non invasive plants in the affected area.
- NEVER compost giant hogweed after removal. Dispose of in a landfill or incinerator.
More Information Available:
Check out our video on Giant Hogweed Identification