Introduced as an ornamental plant, the giant knotweed was not only uprooting road surfaces, it has delayed the building of a hospital, and is now a major problem on the banks of the Laune — one of the county’s major rivers.

Fianna Fáil councillor John Francis Flynn called for “a knotweed enforcement officer” to be appointed. “It’s out of control along the river bank,” Mr Flynn warned.

The coastal regions of the county are badly affected, and the knotweed is found in the centre of Ballylongford, on the Shannon estuary, in Dingle but also inland in Killarney where several clumps along the N22 are being treated, previous meetings have been told.

Spraying not cutting was the only solution as even tiny fragments of the knotweed can cause it to spread.

However, Killarney Fianna Fáil councillor John Joe Culloty astonished his fellow councillors with a suggestion the dreaded plant might be eaten.

Mr Culloty had attended a conference in Caherdaniel on tackling knotweed and he had tasted its shoots and it was “like rhubarb”. Not only had he eaten the shoots, but he had also eaten knotweed jam, he said. There was also a knotweed wine, the council heard.

“You can cook knotweed. It tastes like rhubarb — but maybe this was the way it was cooked,” he said.

He said the plant had “significant medicinal” properties — referring to the high levels of vitamin C which the young spring shoots hold.

It had to be eradicated, but the council might look into using the plant for food as a way of curtailing it, he said.

“It could even cleanse the council chamber,” Independent councillor Michael Gleeson said in exasperation. He had begun the drive against knotweed, calling for war to be declared on it, over the past number of years but was getting no support for his call for a special presentation to the council on the subject.

Kerry County Council has set aside a €100,000 war chest in its knotweed battle.