50 locations in north Cork are home to invasive plant species
Cork County Council have confirmed that there are approximately 50 known locations across north Cork where they are treating invasive plant species and 60% of those are for Japanese Knotweed, while 40% are Himalayan Balsam.
Engineers for the council confirmed that they have been successful in eliminating the species with three to four consecutive years of treatment.
There are laws in place for the control of plants, and with relation to Japanese Knotweed it is an offence to plant, disperse or cause the spread of the plant, or to keep any ‘vector material’ like soil that could breed, distribute or release spores of the plants.
Introduced to Ireland as a decorative plant, Japanese Knotweed grows rapidly and can grow through concrete and tarmac, causing structural damage. The eradication of the plant is difficult and costly; for example, the removal of the plant from the Olympic Village in London cost an estimated £88 million.
In Japan, the plant grows in a considerably more hostile environment, in places getting covered with volcanic ash, and competing with other plants like bamboo, giant grasses, and is victim to an insect that feeds on the plant. However, it seems unstoppable in more accommodating environments.
While glycophosphate, popularly known as RoundUp, is used to treat the weed, with a growing focus on the harm that is caused by weedkiller other methods may need to be researched. In the UK, researchers are assessing the pros and cons of introducing the psyllid Aphalara itadori (the Japanese Knotweed-eating insect) into the British countryside.
Himalayan Balsam is frequently seen along riverbanks, liking wet conditions. It can grow up to three metres, and its seed pods explode, scattering seeds up to seven metres away. It outcompetes Irish native plants for space, light and nutrients, lacking natural predators and pathogen.