• home
  • youtube
  • twitter
  • facebook

Invasive Species Research Conference

Turning Science into Action! Co-hosted by Thompson Rivers University and the Invasive Species Council of BC. learn more »

Parrot's Feather

A popular aquatic garden plant that spreads with water currents, animals, boats/trailers and fishing gear. Dense stands can stagnate water, and increase breeding grounds for mosquitoes

Zebra/Quagga Mussels

These tiny freshwater mussels clog drains, damage infrastructure, and are very costly to control/eradicate learn more »

Giant Hogweed

A towering toxic invasive plant with WorkSafe BC regulations learn more »

European Fire Ant

A tiny ant with a toxic sting learn more »

Purple Loosestrife

An aggressive wetland invader that threatens plant and animal diversity learn more »

Japanese Knotweed

Grows aggressively through concrete, impacting roads and house foundations learn more »

Spotted Knapweed

A single plant spreads rapidly with up to 140,000 seeds per square metre learn more »

Scotch Broom

An evergreen shrub that invades rangelands, replaces forage plants, causes allergies in people, and is a serious competitor to conifer seedlings learn more »

Orange Hawkweed

Also yellow, these invasive plants replace native vegetation along roadsides, and threaten areas not yet reforested learn more »

Giant hogweed

Species
Heracleum mantegazzianum

Giant hogweed (Heracleum mantegazzianum), 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.

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.

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. 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.

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. WorkSafe BC has issued a Toxic Plant Warning for Giant Hogweed that requires workers to wear heavy, water-resistant gloves and water-resistant coveralls that completely covers skin while handling the plants. Eye protection is also recommended.

A few native and ornamental alternatives to plant instead of Giant hogweed include: Blue Elderberry; Ligularia; Rodgersia; Shieldleaf Rodgersia; and Wild Celery. Read more about these alternatives in the Grow Me Instead booklet for BC.

For more information:

TIPS Factsheets

Gallery: Giant Hogweed