Folgendes habe ich in der Kerry Gems Broschüre gelesen (werde nicht übersetzen, da Ihr ja vermutlich als Reiseexperten gut englisch könnt).
"RHODODENDRON Ponitucum was introduced into Ireland from Spain and Portugal in the early 1800s as ground-cover for game. Today it is a serious threat to Killarney's oakwoods.
It spreads rapidly, each branch taking root whereever it touches soil. With its shiny leaves and dense cover, only 2% of sunlight reaches the forest floor, which eliminates other plants and dramatically reduces the biodiversity of woodlands. As it contains toxins, nothing eats it. Just one flower head can produce 7,000 seeds. To make matter worse, it has been found to be a carrier of 'sudden oak death', although rhododendron itself is immune to it."