Tees Operation Giant Hogweed – ID & Risk Awareness

How to spot Giant Hogweed


Plant Description:

  • Found most commonly along river banks
  • Green sharply serrated leaves that begin growing early in March/April
  • Can grow between 3m - 5m (10-16 feet) tall
  • Large hollow stems are ribbed and green in colour with red/purple blotches and sharp bristles
  • Large white umbrella shaped flower heads can be 50 - 90cm (1.5 - 3 feet) in diameter
  • Seed heads produce anything up to 50,000 seeds

See more images and detailed descriptions of Giant Hogweed HERE on the Non Native Species Secretariat Identification Sheet.



CAUTION: Giant Hogweed can cause severe chemical burns to the skin. Avoid contact with any part of the plant at all costs


The Dangers Of Giant Hogweed And
How To Stay Safe

Giant Hogweed poses a significant risk to human health.

Similar to a nettle, brushing against the plant with bare skin causes micro-droplets to be deposited by the plant through tiny pores in the leaves and stem.

However, unlike a nettle, the sap of the plant is phototoxic.  The sap of Giant Hogweed contains toxic chemicals known as furanocoumarins. When these chemicals come in contact with the skin, in the presence of sunlight, they can cause severe burns and blistering which occasionally has led to hospitalisation.

The stronger the sunlight, the worse the effects tend to be. The effects of these burns can last for several months and leave the skin sensitive to sun light for a number of years.



If you get Giant Hogweed sap on your skin, wash the affected area as soon as possible with cold water and soap and cover for at least 48 hours.

Please also be aware of affected areas where dogs may enter. Although your dog’s fur will likely keep it safe from Giant Hogweed burns, the sap may sit on their coat and transfer onto your skin and cause burns on your skin as a consequence.