Japanese knotweed is continuing to spread throughout the United Kingdom. Although attempts at Japanese knotweed eradication are quite intensive, weed control is still needed as the knotweed remains a significant problem.
The Victorians saw the first introduction of Japanese knotweed. Control of the invasive weed at that time was not considered necessary. However, after many years of freedom Japanese knotweed removal has become essential. As Japanese knotweed thrives away from its original habitat of volcanic and other harsh conditions, the United Kingdom has a perfect climate; consequently, the control of the plant is becoming more and more important. Japanese knotweed eradication is particularly difficult as the nature of the plant means that it grows quickly and weed control is necessary to stop regeneration as the roots will spread quickly; up to three to four inches a day.
Japanese knotweed removal is essential because the plant is very threatening as it can grow through parts of buildings, damaging foundations, drains, and even walls. Also, without effective Japanese knotweed eradication, the rhizomes (roots) of the Japanese plant can still continue to grow underground and appear elsewhere. Japanese knotweed removal does not always solve the problem. Weed control is also needed even after a site has been treated to maintain a Japanese knotweed free area.
Japanese knotweed spreads entirely by vegetative means. They reproduce through small pieces of stem and root cuttings. Therefore spreading the rhizomes on sites will exacerbate the Japanese knotweed problem, causing the need for further eradication.
As Japanese knotweed is such a virulently invasive plant, knotweed control needs to be applied to more than just the ability for it to spread from small pieces of root material. The plant typically springs up in April, when it begins its determined growth in all directions. Thousands of pounds can be added to site costs for Japanese knotweed eradication, it can grow anywhere on all sites across the United Kingdom. Its original habitat is harsh and the climate in the United Kingdom encourages its development, often enveloping our native vegetation. Leaving the problem of even a small amount of Japanese knotweed unchecked is a mistake as its fast growth and high voracity means it will grow to form a new plant from just a fragment of root. Therefore Japanese knotweed is becoming more and more common on sites that are disturbed by human activity including, in particular, many areas where development has been planned.