Friday 14 December 2018

Knotweed and how to manage it

Public meeting in Ballydesmond

One of the warning signs erected by Cork County Council
One of the warning signs erected by Cork County Council

Bill Browne

Signs erected by Cork County Council bearing the warning 'Japanese Knotweed, do not touch' can be seen on ditches and along roadsides all across the north Cork area.

But, do you know why they are there and why the invasive plant is such a serious threat to biodiversity? If not, a free information evening entitled 'Knowing Knotweed' set to take place next Tuesday evening at 7pm in the Liscarroll Community Centre will tell people all about the species and how to prevent its spread. 

The seminar is being organised by ecologists and concerned citizens with assistance from Ballyhoura Development and Local Agenda 21 through Cork County Council.

It will be delivered by local ecologist Lee-Jane Eastwood, who will draw from the experiences of Feale Biodiversity, a group dedicated to eradicating invasive alien species from the River Feale catchment area and restoring native flora and fauna. 

Japanese Knotweed is now recognised as being one of the worst invasive species in the world due to its serious impact on biological diversity, the damage it can cause to the built environment and its capacity to spread rapidly. It grows readily by roadsides often causing damage to road and nearby structures. It also grows on hedgerows, often forming large thickets that kill native species, and on riverbanks where it can affect flood defences and increase the risk of flooding. In Britain, some people are even finding it difficult to get mortgages in areas affected by the plant. 

Eradication of Japanese Knotweed can be difficult and costly. For example, its removal from the Olympic Village site in London cost an estimated £88million.   

People finding on their land are advised not to strim, cut, flail or chip plants as tiny fragments can be transported to other areas by footwear, tools or machinery and regenerate within days, spreading its growth and making it even more difficult to manage the plant.  

Cutting can also lead to more vigorous growth both above and below ground, making eradication even more difficult.  

While it can be controlled through the use of appropriate herbicides this needs to be done by a competent expert, with great care given to disposal of dead plants and the treatment of contaminated soil. 

During the evening people will be given leaflets on how to manage Knotweed. Local county councillor John Paul O'Shea urged people, and in particular local landowners, to attend the information evening. 

"The aim is to increase local awareness of Japanese Knotweed and help prevent its accidental spread across the north Cork region," he said.