'It's a 20 to 30 year battle to get rid of this Frankenstein' - park ranger on war against rhododendron infestation
Killarney National Park has been waging a “twenty or thirty year battle” on mature rhododendron plants which have infested the area for over half a century.
Last September, two walkers became disorientated in dense rhododendron and had to be rescued, and last February Kerry TD Michael Healy Rae said the plant infestation was so bad that the army would need to be brought in to deal with the problem.
The plants can grow several metres high, and they can live for hundreds of years.
Since the 1980s, rangers have tried many ways to kill the plant, eventually settling on the environmentally friendly method of stem injection.
Killarney National Park conservation ranger Peter O’Connor says 75 per cent of the rhododendron infestation is now under “active management”.
“You can just inject the stem. You can kill a 100 year-old plant in 30 seconds. You make cuts into the stem, and put tiny amounts of herbicide into it.”
“There are thousands of species of rhododendrons worldwide and there’s only one that’s causing the problem. It’s the rhododendron ponticum, brought into Britain from the Iberian peninsula in the 1800s.”
“I often refer to it as 'rhododendron Frankenstein' because this original rhododendron was mixed with another one, and it’s very hardy, frost won’t kill it, the drought won’t kill it, animals won’t touch it because there’s a toxin in the leaves.
“It blocks out all the light, and shades out all the plants underneath on the woodland floor, and all the associated animals are gone as a result of that. It’s a major ecological problem, it has a huge effect on the biodiversity.”
The rhododendron ponticum was sown outside gardens of country homes in the early 19th century, because hunters liked the cover it gave for birds like pheasants.
And when the sica deer population increased in Killarney National Park in the 1960s, the deer ate and cleared the woodland floor, which in turn made ample room for the rhodendron to take hold.
“Any of the extensive areas in Killarney where the rhododendron is growing, two got people lost in it recently and spent the night in it, those plants are 80 to 90 years old.”
Some 3,000 hectares of the 10,000-hectare national park have been affected by the rhododendron - either a light or heavy infestation.
“We have 75 per cent of that 3,000 hectares under active management, it has been cleared and now under active management.”
“We have an all-year-round volunteer programme, where students come from abroad and spend three to six months in the park volunteering their services. We have eight to ten of those volunteers all year round, and they clear the smaller rhodendron plants.”
For the past few days, Killarney Chamber of Tourism and Commerce, Haven Pharmacy and the Irish Men’s Sheds Association have been helping to manage the rhodendron.
“The 25 per cent of rhododendron that’s still not touched - the virgin rhododendron, it would take millions and millions of euro to bring it under control. Those are 60 to 80 year old plants.”
“It’s a 20 to 30 year battle – killing the mature rhododendron and keeping the site clear. They have to be dealt with over time.”
He added: “A lot of the sites we’re maintaining are in very good order. The main thing is we prevent the young plants from producing seed. That’s the bottom line.”