Japanese knotweed (Fallopia japonica) is a highly invasive plant species that is not native to Ireland. It was originally imported from East Asia during the Victorian era as an ornamental garden plant. It is widespread across every county including Galway & Mayo. It thrives in Ireland's mild, wet climate. From our surveys, we have noted it more in areas where it can grow without hindrance, in particular along abandoned railway lines and adjoining rivers and streams. However, we have also seen it along public roads in rural areas.

It can be identified through its red stem that has a ‘zigzag’ or left to right shape between leaves. Some variants have a white flower (in summer) but the leaf of the plant has an intense green colour, that often stands out and is one of the most striking things about the plant. The leaf is an almost heart shape, and is very recognisable, but it can also be mistaken for Bindweed, as it has a similar leaf shape. We have also seen variants such as Giant Knotweed and Himalayan Knotweed in our work.