Parasitic Japanese knotweed threatens road safety
Japanese knotweed is a parasitic plant that grows everywhere in Flanders and threatens to become a safety problem growing over road signs and damaging the road surface. So far there is no effective way to control it, says the Flemish Agency for Roads and Traffic (AWV) which is maintaining the road network.
The invasive plant was imported in Europe years ago from a botanical garden in London. This Japanese knotweed grows so fast that it threatens road infrastructure. Its roots can even damage the foundations of the roads. As the plant grows 10 centimetre a day, it becomes a plague.
No mowing allowed
“The moment we are identifying new zones with the plants we mark them with red tape to avoid mowing because this enhances growth and distribution”, says Veva Daniëls, spokeswomen of AWV). “Only if it endangers road safety our people are allowed to mow manually”.
Even out of the smallest cut of parts, new plants can grow, explains Tim Adriaens of the Instituut voor Natuur- en Bosonderzoek (INBO).
A legal weed killer that removes knotweed doesn’t exist. Also in the rest Europe this pant becomes a problem. “In the Netherlands the Japanese knotweed has been spreading so widely that it may cause damage to infrastructure and even houses”, says Rob Leuven from the Radboud University (Nijmegen).
“Everyone is looking for a solution. Some countries use pigs, goats or sheep to eat the knotweed. In Germany the soil is removed and treated with steam. All these solution work temporally and are very expensive”.
“In the United Kingdom searchers run an experiment to bread the Japanese leaf flea. This flea only eats Japanese knotweed and if the experiment works, they might also be used in Flanders.”,