A couple in their 50s had to be rescued from a dense rhododendron forest after they became trapped in a "treacherous area" on an Irish mountainside.
The five-hour rescue operation took place in the Knockmealdowns Mountains, which straddle the border between County Waterford and County Tipperary.
The couple, who are experienced hill walkers, got into difficulty on steep ground overlooking Bay Lough on Sunday.
One of the rescuers said the plants were "like an impenetrable jungle".
Jimmy Barry from the South Eastern Mountain Rescue Association said the rhododendron forest was so thick and deep that people could not hear each other.
"It was horrendous - I have been a member of mountain rescue for 15 years and it was probably one of the most dangerous exercises or rescues I've been on," Mr Barry told BBC Radio Ulster.
The couple had lost their way on a hillside that sloped down to a lake.
The rescuers located them quickly and managed to get into a position no more than 400 metres away, but did not anticipate how difficult it would be to reach the couple through the dense vegetation.
"We sent the first party of five in - I was in that party - and within 50 metres, we couldn't move. It was like a jungle and it was horrendous, because everything dies underneath rhododendron," Mr Barry said.
"And it was messy, we had to crawl through it, carry our gear and then try and locate the people as well."
He said he had never seen his rescue team struggle so much among rhododendrons, and it took them two hours to walk about 350 metres.
"We kept going," he told the programme. "Two hours later we finally reached the two people inside the middle of the rhododendron forest, and then the fun began, because we had to decide how we were going to get out of it."
"We were 100 metres from the edge of the lake, so we decided to literally drop down through the forest," he added.
The plant's dense foliage tends to block out sunlight and kill off surrounding vegetation.
Mr Barry said this meant the rhododendron forest had produced very difficult terrain on the mountainside.
"It's regarded as a weed. It's not a native plant to Ireland or any part of the British Isles and they've just gone wild," he said.
"It looks beautiful, but underneath it nothing of our native plants grows, and it's just horrible in there.
"Dangerous, because where it was growing on the side of the lake, it's very steep ground, so we were literally walking on rhododendron.
"We could look down through the rhododendron and see 10ft drops, 20ft drops and at the end we were looking at a 50ft drop, but we had to go down through it to get out."
The couple and their rescuers eventually reached the lake where they were picked up by a boat and taken to safety.
Mr Barry said the couple were not hurt but were "tired and very, very relieved".
He added that his team was "exhausted" following the rescue.
The multi-agency operation also involved Cahir River Rescue and the police.
'Risky and arduous'
On their Facebook page, South Eastern Mountain Rescue Association said they were able to make visual contact with the stranded couple and then "guided rescuers in by radio to the location in very dense rhododendron forest".
"To avoid a risky and arduous trek back up the slopes of Knockshanahullion, Cahir River Rescue responded to help complete the last leg of the journey, transporting the two along with mountain rescue personnel across Bay Lough to safety," the Facebook post added.
The association described the operation as a "good result".