Giant Hogweed is biennial or monocarpic perennial flowering plant. This means that from seed, the plant takes two years (biennial) for it to complete its lifecycle to produce its own seed after which it dies (monocarpic). It can grow up to heights ranging between 2 and 5.5 metres making it a considerably large and fast growing plant.

 

This excessive size and growth rate shade out other slower growing, native plant species to the point where they cannot compete and so the Giant Hogweed becomes the dominant species, reducing biodiversity in an area and disrupting environmentally sensitive habitats. It can produce up to 50,000 seeds which can remain viable in the surrounding soils for up to 15 years ensuring that its presence remains.

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It grows mainly along river corridors where seeds can be transported down river where it can re-establish itself in new areas although it is not uncommon to see it occur in other environments.

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As the plant dies back in the Winter and its preferred habitat is along river corridors, this leads to situations where river banks can become destabilised as the river banks then become exposed exacerbating erosion.

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IMPORTANT: Giant Hogweed is a phototoxic plant as the sap of the plant can cause phytophotodermatitis. This means that exposure to the sap from the plant on the skin can result in severe, painful blisters if the sap is further exposed to sunlight (UV radiation). DO NOT CUT OR STRIM THIS PLANT.