Japanese knotweed invasion widens grip as farmers and gardeners are warned of risk
Farmers and gardeners have been warned that planting or recklessly allowing Japanese knotweed to spread to another property could result in a prosecution.
The warning came as experts stressed the scale of the national problem posed by the invasive Asian species has been underestimated.
Japanese knotweed remains a problem in gardens, ditches, wasteland and woodland nationwide despite an expensive campaign by councils over recent years to eradicate it.
Scientifically known as Fallopia japonica, the plant was introduced to Ireland by landscape gardeners in the 1850s when its full characteristics were not understood.
It is so aggressive that, once established, it spreads to dominate entire areas, forcing out native plant species.
Its extensive root network also makes it exceptionally difficult to remove - and its roots can cause property damage.
The National Biodiversity Data Centre stressed Japanese knotweed is a strictly regulated species.
"Under Regulation 49 (2) any person who plants, disperses, allows or causes to disperse, spreads or otherwise causes to grow Japanese knotweed shall be guilty of an offence," it stated.
Botanist Dr Frances Giaquinto said it was now an issue in every Irish county.