https://www.thesun.ie/news/5080611/dangerous-japanese-knotweed-illegal-dumping-dublin/ DANGEROUS Japanese Knotweed is being spread by illegal dumping, experts say. Council biodiversity officers tasked with trying to contain the invasive plant have revealed that its growth is most prevalent along waterways. The Asian plant, which has been wreaking havoc all over Ireland, can undermine the structural integrity of roads and buildings if it begins to grow in cracks and crevices.