Giant Hogweed

Giant Hogweed Heracleum mantegazzianum is an 'aggressive competitor', able to out-compete native plant species, reducing the amount of suitable habitat available for insects, birds and mammals.

Giant Hogweed produces approximately 1500 seeds per flower head in late summer. These seeds can remain inactive in the soil for several years. The movement of soil polluted with Giant Hogweed seeds must be carefully controlled to prevent the spread of the plant.

Dr Lindsay Stenhouse investigates the dangers of Giant Hogweed in Scotland, in a video first broadcast on Landward in August 2007. Image courtesy of Jean-Pol Grandmont.

Giant Hogweed contains a substance within its sap that makes the skin sensitive to ultraviolet light. This can result in severe burns to the affected areas, producing swelling and severe, painful blistering. Damaged skin heals slowly, leaving residual pigmentation that can develop into Phytophotodermatitis, a type of dermatitis that flares up in sunlight and for which there is no straightforward treatment.

DermaNet NZ advises that contact with dead plant parts, pets or other objects which have been in contact with Giant Hogweed parts is dangerous, and protective clothing and goggles and the avoidance of sunlight are necessary during the extraction of the plant.

Due to the density of stands of Giant Hogweed and the safety implications involved in the removal of the plants, footpaths and other amenity areas can be rendered unusable by the presence of this species.

Page first published on Wednesday 2nd September 2009
Page last updated on Wednesday 2nd September 2009


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