Ballyhoura Development has been working with local landowners and with Limerick Co. Council to eradicate Giant Hogweed along the Loobagh river catchment, from the headwaters down to Bruree, since 2014.

Giant Hogweed is an invasive alien species which is regulated for control by two pieces of EU legislation because it causes a serious burn on contact with skin, it spreads very fast by seed, and it destroys native biodiversity.  Giant hogweed is not native to Ireland, and causes serious economic and environmental damage.

Giant Hogweed can grow up to 5 metres in height Project History

As part of Limerick Co Council’s strategy to restore biodiversity on the River Loobagh, Ballyhoura Development has been working with landowners to try to eradicate the plant.  The first eradication project, in 2014, led to a 50% reduction in severity of the infestation in the area.  At the same time, it became evident that it would be impossible to eradicate it entirely until the plant was eradicated from the upstream part of the catchment, since the seeds flow downstream in the river.

To address this, a complete survey and full eradication strategy was devised in 2018, and in 2019, funding was awarded through the National Biodiversity Action Plan, for a 3 year project to eradicate Giant Hogweed from the entire length of the River Loobagh. 

Current Project

The River Loobagh Giant Hogweed Eradication Project will run until 2021, and aims to restore native biodiversity and prevent the growth of secondary invasive species such as Japanese Knotweed. The project also aims to establish a best practice model for eradicating invasive species without the use of herbicides and other chemicals.

The project is led by Limerick Co Council, in partnership with Ballyhoura Development and local landowners, and the unique feature of this project is that the plant is being eradicated without the use of herbicides.  While this approach is labour intensive, it is environmentally friendly.

The project follows a two pronged approach of cutting flowering heads and digging up new plants.  This will continue for another 2 years.

To do this, a team of trained community volunteers and Rural Social Scheme staff from Ballyhoura Development cut the flowering heads, to reduce the seedbank in the soil.   The team then manually digs out out new plants as they emerge.  Plants on steep banks which are inaccessible are tackled at times of the year when the river level is lower.

Hand in hand with the eradication programme, the project focus is on restoring the native vegetation of the river banks to prevent secondary invaders such as Japanese knotweed and Giant Butterbur.

Species records are being created for each area and there is good native biodiversity. This method of digging out the Giant Hogweed will facilitate rapid recolonisation by native species without much intervention because there is minimum disturbance to existing ground cover.

The success of the project to date is testament to the high levels of cooperation and support from landowners, their willingness to help, and their interest in addressing this significant environmental challenge.