Biosecurity Awareness

In Ireland,  Japanese Knotweed and all other plants listed on the Third Schedule and subject to restrictions under regulations 49 & 50 are classified as controlled waste.

Japanese Knotweed thrives on disturbance and invades environments where soils are routinely disturbed and transported.

• Do not strim, cut, flail or chip the plants as tiny fragment can regenerate new plants and make the infestation harder to control
• Do not attempt to dig out Japanese Knotweed, this can actually encourage the plant  into growing faster, therefore colonising an area more aggressively
• Do not move or dump soil which may contain plant material as this may also add to its spread.
• Do not attempt to pull the plant out of the ground, as this can expose part of the infectious crowns, stimulating growth
• Do not use unlicensed herbicides close to any watercourses, plants or wildlife
• Do not compost any part of the plant as due to the resilient nature of knotweed it could survive and grow on when the compost is ready for use
• Do not dispose of Japanese Knotweed in garden waste allotments as this just transport the plant to new locations
• Do not spread any soil that has been contaminated with Japanese Knotweed rhizome as new plants will sprout
• Do not do break the law – Remember it is an offence if you cause the spread of Japanese Knotweed either intentionally or unintentionally.

Lack of awareness about how the plant spreads has meant that hedge cutting contractors, developers and people in general have been spreading it unwittingly for years.

Every Japanese Knotweed plant in Ireland is female, the only way that it can spread is through rhizomes or fragments of its own vegetation breaking off and re-growing.

Cutting it to try to get rid of it actually helps it to form new plants and continue to spread.

It is common where there is a roadside area of knotweed, to find more stands of it further down the road where fragments from the flail cutter have landed in previous years and regrown.

Strimming is a very common way for homeowners and landowners to maintain their gardens, ditches and hedges, in fact strimming is the very worst thing that you could do as it creates millions of tiny pieces, each of which has the potential of developing into a new plant.

The spread of Japanese Knotweed was accelerated hugely in the Celtic Tiger years here in Ireland, contaminated soil was routinely disturbed and transported during construction and road building projects in both the rural and urban environments.

Equally damaging were the subsequent recession years, where there was the dawn of the “ghost estate” abandoned, unfinished housing developments littered the country – housing estates that were built on sites with contaminated soil present.

The unfinished nature of these housing developments provided ample opportunity for deep seated establishment of Japanese Knotweed.