Giant hogweed (Heracleum mantegazzianum)

Giant Hogweed is a very tall, robust plant growing 3-6 m tall with large leaves, hollow stems and white flowers at the top of the stems. It flowers from May to August and is found in grassy and waste places, particularly in areas close to water (for example, beside rivers and canals).

Skin contact with Giant Hogweed, in the presence of sunlight, can cause severe skin reactions and even burns. Problems can result from cutting the plants e.g. while strimming, or sometimes only from touching plants, in combination with exposure to sunlight.

The sap from Giant Hogweed makes the skin extra sensitive to ultraviolet light. Exposure to sunlight then causes redness, swelling and burns within 24 hours.  Large, fluid filled blisters may develop within 48 hours. The affected areas can be very itchy and painful and it may take several days for these symptoms to improve.  Brown pigmentation and scarring may last for several months and the affected areas may remain hyper-sensitive to ultraviolet light for years.

If you come into contact with Giant Hogweed wash the exposed areas thoroughly with soap and water, as soon as possible.  Then cover the exposed area and/or apply sun block to protect your skin from sunlight for at least 48 hours after exposure, even if you have no symptoms.  See your GP if you develop any symptoms.