What is Japanese Knotweed?
Japanese knotweed is a long-lived perennial which is in many ways quite attractive. It grows quickly, has a stem that is similar to bamboo, and has small creamy white flowers in late summer. It was introduced to the UK from Japan about two hundred years ago as an ornamental plant. You might not have heard of Japanese Knotweed if you have not been involved in buying or selling property lately. You may have this species present on your property and not be aware. While it is not an offence to have it on your land, there is legislation in place to prosecute in situations where the plant is either allowed to spread into the wild, or if it impacts upon a neighbour.
Why is it a problem?
The problem is that Japanese Knotweed is an extremely aggressive plant. The underground root or rhizome structure is as large as the above ground plant and spreads quickly, particularly in disturbed ground. Whilst it is unlikely to damage a sound building to the point of structural damage, the ability of the plant to exploit even a minor weakness or void means management of the species is important. Aside from structural issues, the plant is a major threat to local ecosystems, quickly out competing our humble native species and turning local areas into ecologically homogeneous landscapes.
How can it affect my property?
You must declare the presence of the plant when you sell your home. The plant does have the means to damage built structures in some circumstances as well as putting the owner in a position where legislation is breached. If you are buying a property with knotweed present the correct management plan must be in place via a suitably qualified specialist otherwise you may not be able to get a mortgage. The situation is similar if you wish to raise finance against such a property.
Can I eradicate myself?
The simple answer is yes. You would be in breach of legislation, through taking the plant off your premises however, and if you facilitate its spread into the wild or off-site. However, you would still have to declare it had been on your land in the past when you sell your home, and if there was no suitable management plan in place, it is unlikely mortgage companies would issue a mortgage. Furthermore, if herbicides were used, the word “eradication” is inappropriate. The chances are, the plant has been sent into a temporary dormant state i.e. the foliage has been killed but the rhizome still remains viable. In both cases, self-treatment causes more problems than it solves. Having the correct management plan in place, using a specialist company is essential.