In Heerlen, Geleen and Herten, trials are being conducted to combat Japanese knotweed.
The plant was once brought to Europe from Japan as an ornamental plant. It was soon discovered that the plant is very invasive. “A bud or even less than one gram of stem is enough to create a new plant,” explains expert Jean-Pierre Duijsens.
Test with tubes
In a trial that is being done, tubes are placed around the roots. “We ensure a desired temperature in those pipes. We cook the roots, as it were. After two weeks we see what the effect is on the roots.”
Other plants broken
It is important to also check what consequences this has on the flora around the knotweed. “Obviously you don’t want other plants to be destroyed as well. But on the other hand, if you don’t tackle the knotweed, it will cause other plants or the road surface to break.”
Fight or control
There are several ways to get the Japanese exotic from your garden, explains Duijsens. “You look at control and control. That is sometimes also a cost and you cannot apply the same technique everywhere.”
Europe
People want to get rid of the plant not only in Limburg, the rest of the country and in various places in Europe are also looking at what can be done against the Japanese knotweed. “There is a list of invasive exotics at the European level. The giant hogweed and the Asian hornet are on it, but the knotweed is not. That meant that there was no obligation to do anything about it. But there is now more and more increased the pressure to do something against the plant.”
According to Duijsens, there are already places with so many specimens of the plant that it is difficult to control them alone.