In the words of the well-known football commentator, this is ‘a game of two halves’. When it comes to Japanese Knotweed, there is definitely some good news and equally some bad news.
The bad news is that, as weeds go, Japanese Knotweed is something of a bully. It can lay dormant for years, but when it grows, it can extend a metre in a month and can cause damage to a range of materials, even concrete surfaces. If you leave the weed to develop, it is likely to affect your neighbours. It is an offence to allow the weed to grow unchecked.
The good news, though, is that If you have Japanese Knotweed in your plot, it can be treated and controlled. Often this takes more than one treatment. There is a code of practice that details how knotweed should be managed and disposed of. Contractors who dispose of the waste should be registered with the Environment Agency. There is now good advice available from many sources as to how you can control and, ultimately, eradicate it.
Spencer Bray can help you find a good specialist if you face this problem.