Japanese invader is killing off native plants

JAPANESE Knotweed, which seems to be spreading all over west Cork, has now established itself in some important heritage sites and in some areas of outstanding natural beauty where it forms a monoculture, quickly killing off all the native plants.

The Japanese Knotweed Alliance provides information and eradication methods. Its website says the weed spreads by rhizomes deep in the ground and the only way to treat it is by using chemicals which will penetrate the rhizomes.

Cutting back only helps it to spread as fresh stems produce shoots and roots when buried in soil or floated in water.