Giant Hogweed

Giant Hogweed - Heracleum mantegazzianum

Warning! Giant hogweed stem hairs and leaves contain a clear, highly toxic sap that, when in contact with the skin, can cause burns, blisters and scarring.

Identification

Giant hogweed has numerous small white flowers clusters in an umbrella-shaped head, with stout, hollow green stems covered in purple spots. Dark green leaves are coarsely toothed in 3 large segments with stiff underside hairs, and lower leaves can exceed 2.5 metres in length. Giant hogweed can grow up to 5 metres in height at maturity.

Damage

Giant hogweed is a highly competitive plant due to vigorous early-season growth, tolerance of full shade and seasonal flooding, as well as its ability to co-exist with other aggressive invasive plant species.

Habitat

Giant hogweed, also known as "Giant Cow Parsnip," is a perennial and currently distributed in the Lower Mainland, Fraser Valley, Gulf Islands, and central to southern Vancouver Island.

In Delta, this plant can be found along the Roberts Bank Dike. A management strategy is currently being developed for control of this plant.

Spread

Each plant can produce up to 100,000 winged seeds (typically 50,000) that remain viable in the soil for up to 15 years. Plants generally die after flowering.

For more information about this plant please visit:

• WorkSafe BC
• Greater Vancouver Invasive Plant Council
• Invasive Plant Council of BC
• BC Ministry of Agriculture and Lands