Giant hogweed (Heracleum mantegazzianum)

Giant hogweed (Heracleum mantegazzianum)

Introduced to Ireland as an ornamental plant over a century ago.

Giant Hogweed
Giant Hogweed - Photograph: W. Woodrow


This plant can grow to up to around 4 metres tall and can be found mostly along river banks and damp ground.  It was introduced to Ireland as an ornamental plant over a century ago. It has huge leaves that can be around 1.5 metres across and tiny white flowers that are spread like an umbrella at the top of the stem.  

Problems associated with this species include:

  • It is a health hazard! -  The plant produces a sap that can cause extreme blistering to the skin, particularly in the presence of direct sunlight.
  • Loss of biodiversity as native species are shaded out
  • Increased erosion as it stops plant growth beneath it in the summer and dies back in winter leaving bare river banks open to erosion
  • The combination of its large size, associated health hazards and fondness of river banks means that it reduces riverside access where it becomes a problem.
Giant Hogweed
Giant hogweed - Photograph: W. Woodrow

Where is it in Meath? 
Giant Hogweed tends to occur mainly along water courses, although it can also be found just on damp ground.  It has been recorded in Meath in the River Boyne / River Nanny area in the east of the county, and the Royal Canal in the south.  It is likely that it exists, unrecorded, in other parts of the county.

What can you do? 
Safety first - Don’t touch and keep children away from it.
This species needs to be controlled by chemical treatment (see Best Practice Management Document link below).

Report all sightings: 

To Meath County Council -  046 9097150 or email
To Invasive Species Ireland database - 

Download Best Practice Management Document from Invasive Species Ireland to help tackle this species - 

Download ‘How to manage Giant Hogweed at home’ leaflet from Invasive Species Ireland -