Giant Hogweed (Heracleum mantegazzianum) seeds travel down the Thames and take root on riverbanks and floodplains in the County. They spread further down the Thames yearly and create issues with riverbank stability leading to erosion, grow quickly and outcompete native vegetation, and grow in large groups which leads to decreased riparian biodiversity.
Giant Hogweed (Heracleum mantegazzianum) can be a serious health hazard for humans. Its watery, clear sap contains photosensitizing compounds, which, when in contact with human skin and in combination with UV radiation, can cause burning. Content varies depending on the part of the plant, but contact should be avoided at all times. The reaction of the skin depends on individual sensitivity.
Giant Hogweed (Heracleum mantegazzianum) flowers grow in large clusters. Photo by Invading Species Awareness Program.
Giant Hogweed (Heracleum mantegazzianum) flowers and leaves on a mature plant. Photo by Invading Species Awareness Program.
Young Giant Hogweed (Heracleum mantegazzianum) plant before flowering occurs. Photo by Invading Species Awareness Program.
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