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Giant hogweed - Heracleum mantegazzianum

Habitat:
Giant Hogweed is a terrestrial plant found  primarily on riverbanks and canal corridors.

Status:
Hogweed was first identified in Ireland in the late nineteenth century and is now widespread.

What does it look like?
The plant is distinguished by a stout, dark reddish-purple stem and spotted leaf stalks that are hollow and produce sturdy bristles. It flowers from late spring to mid summer, with numerous white flowers clustered in an umbrella-shaped head.

Impact:
The plant is potentially harmful to humans as the sap can cause third degree burns. Giant Hogweed out-competes native flora in itís habitat and as it dies back in the winter, river banks are often left open to erosion. This leads to the alteration of freshwater systems with an increase in nitrates and phosphates that leads to an increase in aquatic plant growth posing a risk to fish life, in particular, salmon spawning.

Where is it originally from?
Giant Hogweed originated from Caucasus, Central Asia and was introduced as an ornamental plant.

What can you do?
The plants should be sprayed with herbicide; however cutting the plant down can also be effective once appropriate safety measures are taken. Go to the Invasive Species Ireland website for more information.

©2007 Department of the Environment, Heritage and Local Government