Giant Hogweed

Giant Hogweed is straightforward to identify, but has severe safety issues when in close contact with humans and animals. Introduced as an ornamental plant, its appearance is similar to cow parsley but on an enormous scale, growing up to 6m in height.

Foliage creates a dense canopy over surrounding land, smothering native flora and seriously affecting biodiversity. Giant hogweed thrives beside watercourses, causing erosion of riverbanks.

On contact with the skin, causes photodermatisis and can cause blindness from the chemical Furanocoumarin.


Giant Hogweed is proscribed under the Countryside and Wildlife Act (1981) and requires Duty of Care under the Environmental Protection Act (1990) due to both its invasive and toxic nature. The watery sap of the plant contains harmful toxins that cause photo-dermatitis and can cause blindness. After exposure to sunlight, painful blistering occurs where the sap has come into contact with skin. The effects may not become apparent for up to 48 hours after contact with the sap/stem.


  • Immediately wash the area of skin thoroughly with soap and water;
  • Protect the area from exposure to direct sunlight by covering with clothing, bandage etc;
  • Seek medical advice straight away;
  • Always wear non-porous gauntlet gloves when examining the plant and also wear long-sleeved and long-legged garments, even the dead stems can give a nasty burn;
  • The use of goggles is essential, especially when undertaking clearance work of the plant.


Leaves - Large with serrated edges that can expand to 1.5m across and 3m long.
Flowers - Inflorescences (circular clusters of small, white flowers) that can measure up to 50cm in diameter.
Stems - The stems are hollow and thick, growing to 10cm across, with bristles and are marked with purple specks.






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