Programme to tackle the scourge of Giant Hogweed on Suir Island in Clonmel

Above - Lyn Mather, Theresia Guschlbauer, Mike Fitzgibbon, Karl Roche, Alan Moore and Dr. Fran Igoe, Regional Director of LAWCO (Local Authority Waters and Communities Office) taking part in a dig to clear Giant Hogweed from Suir Island, Clonmel. 

A novel conservation programme is taking place along the River Suir to eradicate what is one of Ireland’s most hazardous and dangerous invasive plant species, the Giant Hogweed. 

This plant, which can grow to heights of over 15 feet tall, was introduced as an ornamental novelty to this country back in the 1800s, but has since escaped the ornamental gardens where it was first planted. 

It is highly invasive and can produce over 100,000 seeds per plant. More worryingly, however, is the fact that it's a hazard to the public and has been spreading along the River Suir.  

The plant has spread particularly quickly on the fertile soil of  Suir Island itself, posing a health risk to anyone who comes into contact with it. 

Members of Suircan Community Forum and other volunteers from Clonmel and Ardfinnan have been involved in eradicating Giant Hogweed from Suir Island in recent months. 

Several evening sessions have taken place, organised by Suircan Community Forum, in association with Dr Fran Igoe, Regional Coordinator of LAWCO (Local Authority Waters and Communities Office) who is based in Clonmel.

Giant Hogweed is easily recognisable by its very large stems and leaves, which resemble rhubarb.  

It is a particularly nasty and unwelcome invasive plant that can cause quite serious skin burns to those who come in contact with its milky sap, and which unfortunately is flourishing on Suir Island in large clumps. 

This is considered a problem for a number of reasons. Firstly, the River Suir is a key amenity for Clonmel, and the County Council’s Masterplan for Suir Island, developed by Ken Hennessy Architects, aims to develop woodland paths and play areas on the island to allow public access to this beautiful green wilderness.  

In addition, the new canoe slalom course alongside the island and the River Suir Blueway from Cahir to Carrick-on-Suir are attracting kayakers and canoeists to the river and its banks as well as walkers, cyclists and picnickers. 

Giant Hogweed, in common with other invasive species such as Japanese Knotweed and Himalayan Balsam, tends to crowd out and replace native plants, contribute to soil and riverbank erosion and lead to an overall reduction in biodivercsity.

Under the direction of Suircan members, the Hogweed blitzes kicked off on Suir Island car park with a short lecture from Fran Igoe, who took volunteers through a health and safety checklist and then a demonstration of the control method.  

This novel technique was first trialled during the development phase of the Mulkear Life project in the Lower Shannon. It uses no chemicals but targets the roots of the plant by digging early in the growing season. 

This is the first time that the technique has been trialled on a larger scale in Ireland, although in New York State it is now regularly used. Long-sleeved protective clothing and protective gloves are essential when dealing with this plant, and a digging method involving cutting and uprooting below ground level ensures a high level of plant kill. 

The method also avoids handling of the stem or leaves, thus greatly reducing the risk of sap burns.

Further follow-up digs are planned to take out any plants that were missed on previous digs, as well as a review of the efforts made to date.

Clonmel Borough District Council have also initiated a Japanese Knotweed eradication programme on Suir Island. This plant requires a dedicated control programme using weedkiller (glyphosate) and careful follow-up treatment to ensure its complete removal.

According to Alan Moore, Chairperson of Suircan, it is imperative that these plants are brought under control, especially now that the area is being developed as a greenway and a waterpark in Clonmel, which will potentially bring more people into contact with it.

Fran Igoe says that the problem and impact of invasive species came up regularly during the countrywide public consultations on the River Basin Management Plan. There is a broad consensus that that the problem can only be tackled by a combined and concerted effort along each river course. 

Efforts are currently being made to expand the invasive species control programme locally on the River Suir and include other species such as the Himalayan Balsam and Japanese Knotweed. Volunteers are always welcome to take part in these initiatives.

Check out Suircan’s Facebook page or contact the group by e-mail on Suircanclonmel@gmail.com