The Japanese knotweed Problem.
Neil Guthrie works for the Environment
Agency, and has written the following article regarding the problem
of Japanese knotweed, which is now present in our village.
Japanese knotweed along the Hellifield Road |
A plant introduced to Britain in the 19th century as an exotic for
gardens is now spreading throughout the countryside causing damage
and potentially costing millions.
Bolton by Bowland has Japanese knotweed growing along Kirk Beck. At the moment it is not causing a major problem, however it has the potential to create problems for the future. If anyone sees this plant in other parts of the parish please let me know so we can keep track of it. Japanese knotweed, whose scientific name is Reynoutria japonica, is a member of the polygynum family. It grows rapidly spreading through root growth and from plant material spread around or in soil being moved about. In this country there are only female plants (male and female plants being required in this species) and so it cannot set seed. The spread of Japanese knotweed throughout the country has been the result of deliberate introductions or unwitting spreading through contaminated soil or cut material floating down rivers.
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So, why is it a problem? Because it is a non-native plant and very invasive with no significant natural predators. It grows abundantly shading out natural plants, and though it can provide cover for a few animals in general it is harmful to the ecology of the areas it grows in. It can also cause a lot of economic damage as it can grow through tarmac and concrete and has been known to grow into peoples houses. It has been estimated that eradicating it would cost in the region of £1.5billion. It is illegal, under the Wildlife and Countryside Act 1981 to plant
or deliberately allow Japanese knotweed to grow in the wild, however
it is perfectly legal to grow it in a garden. |
Japanese knotweed leaves |
Leaves in more detail |
Controlling Japanese knotweed is difficult. The two best ways are through chemical control or removal of the plant material and contaminated soil and taking it to a tip which can deal with it properly. However as it is capable of growing from even the tiniest amount of material this option needs to be carried out with great care, and the soil is considered to be contaminated for an area of 10 metres from the plant and down to 2 metres. Cutting can control it but the very greatest care must be taken to ensure every last piece of material is disposed of properly either through burial (5 meters deep is recommended) or incineration. Cutting in general is not recommended because of the likelihood of spreading the plant. Sadly, the chemical option (Roundup) is the most effective and least likely to cause further spread. |
I am contemplating setting up a working party to start the process of eradicating this pest from our village. If you are interested in taking part, or contributing in any way, please contact me: My email is neil.guthrie@tesco.net Again, if anyone sees further infestations within the village, please let me know - I suggest you do this rather than try to deal with it yourself.
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Japanese knotweed along Kirk Beck |
