Giant Hog Weed Eradication Programme
A super sized threat to people and plants is beginning to show its white flowered head at a number of locations in County Kilkenny. Giant Hogweed (Heracleum mantegazzianum) is a biennial or herbaceous plant that can grow to 3 - 5m tall and looks very like a large cow parsley. Each plant can produce up to 20,000 seeds a year which can be spread by the wind or over long distances by rivers and streams. It is thought these seeds can remain dormant in the soil for up 15 years before germinating and growing into a new plant.
Giant Hogweed - it should not be confused with Common Hogweed which is native to Ireland and appears similar to Cow Parsley
Giant Hogweed has spread rapidly since its introduction as a garden plant in the 19th Century and is commonly found on damp sites such as the banks of rivers and streams, railway lines and waste land. Giant Hogweed out-competes native flora in its habitat and as it dies back in the winter, river banks are often left open to erosion. This leads to the changes in the rivers and streams with an increase in nitrates and phosphates that leads to an increase in aquatic plant growth posing a risk to fish life.
The sap of Giant Hogweed contains a chemical that can cause the burning, itching and blistering of the skin of any person that it comes into contact with. A number of people who have come into contact with this sap when strimming and cutting Giant Hogweed have had severe burns and burns which are slow to heal and burn like symptoms have been know to appear again for up to 6 years afterwards.
Infestations of the plant have been found on the banks of streams flowing into Lough Cullin, a proposed Natural Heritage Area (pNHA), which is the only natural lake in Co. Kilkenny. Kilkenny County Council has with the assistance of a grant from the Heritage Council and the support of local landowners put an eradication programme in place that will take a number of years to fully remove the problem in the area. The methods used to control the Giant Hogweed include spraying and injection of herbicides into the stem of the plant when the tops have been cut off.
Stem injection of larger plants to ensure chemical reaches the root system
Further information on Giant Hogweed can be obtained from www.heritagecouncil.ie, www.kilkennycoco.ie and www.invasivespeciesireland.com.
