Giant Hogweed


Giant  Hogweed
Heracleum mantegazzianum
Family: Apiaceae (Umbelliferae)
Giant hogweed has been introduced to Europe, the United Kingdom, Canada, and the United States as a garden curiosity.
Because of its tenacious and invasive nature it soon becomes a pest within the ornamental garden and readily escapes. It has naturalized in many of the places where it was first introduced.
Giant hogweed is a member of the parsley or carrot family, Apiaceae (Umbelliferae). As its name indicates, it is characterized by its size and may grow 15 to 20 feet tall. The stem and stalks are hollow. Stems vary from two to four inches in diameter. The compound leaves of giant hogweed may expand to five feet in breadth. Each leaflet is deeply incised. Giant hogweed is a monocarpic biennial to short lived perennial with tuberous root stalks which form perennating buds each year. The inflorescence is a broad flat-topped umbel composed of many small white florets. Each inflorescence may attain a diameter of two and a half feet.
The plant exudes a clear watery sap which sensitizes the skin to ultraviolet radiation. This can result in severe burns to the affected areas resulting in severe blistering and painful dermatitis. These blisters can develop into purplish or blackened scars. Proliferating populations in urban and suburban areas represents an increasing public health hazard. Giant  Hogweed Burns - Photo copyright -  USDA-APHIS
Keep the plant mowed down during the summer to prevent seeds from maturing. Don’t allow pieces of it to land on bare skin. Even after the parent plant is completely removed, the seeds left behind can come up, 7 or 8 years later. Removing the green growth will help to exhaust the root and will weaken the plant, so digging it out and chopping it is feasible.

Roundup weedcontrol manually.

Giant Hogweed is a foreign invader that prevents native plant species from growing.  Under the Wildlife & Countryside Act 1981 / Wildlife (Northern Ireland) Order 1985 it is an offence to ‘plant or otherwise cause Giant Hogweed to grow’ in the wild.  This includes spreading the species or transferring polluted ground material from one area to another.
Any Giant Hogweed polluted soil or plant material that you discard, intend to discard or are required to discard is classed as controlled waste and should be accompanied by appropriate Waste Transfer documentation.

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