If you are considering selling or buying a property then no doubt you will be aware of the damage Japanese Knotweed can do, not only to your property but to a property’s value.

Japanese Knotweed is a highly invasive and destructive plant that can cause damage to buildings, paving and roads.

It was introduced into this country in the mid nineteenth century by a German-born botanist called Phillip V

on Siebold, who presented this and other Chinese and Japanese plant varieties to Kew Gardens.

It is an extremely resilient plant and can grow up to three metres in height, spreading rapidly and pushing up through ashphalt, cracks in concrete on driveways and even grow up into cavity walls and drains, in its quest for light and water.

Japanese Knotweed is not a problem in Japan as it has natural enemies in the form of bugs and fungi, however here in the UK these natural enemies do not exist, allowing it to spread freely.    

Although most people are aware of Japanese knotweed, most would struggle to recognise it as it can be confused with other plants / weeds.

The earlier Japanese Knotweed is spotted, the easier it is to kill. In Spring red or purple asparagus like shoots appear which quickly turn into green bamboo-like stems which grow rapidly, often several inches a day, reaching up to three metres in height.  It is fully grown by early summer and flowers in late summer, when clusters of spiky stems become covered in creamy-white / pinkish flowers. The leaves are green in colour, flat and heart shaped in their appearance. In autumn the plant stops growing and the bamboo-like canes become brown and brittle, often fooling people into believing the plant has died. However, this plant has a rhizome system beneath the ground which lies dormant during the winter months.

The most successful treatment is the use of professional herbicides, consisting of regular treatments over two or more growing seasons. There is also a treatment available which involves digging up the rhizome roots and sifting them out, returning the good soil to the ground.

Trying to control knotweed by cutting it down, burning or burying it, will not work. This plant can lie dormant beneath the ground, only to strike again when people are least expecting it.     

If you are planning on buying or selling a property, this plant doesn’t need to cause you big problems. A seller must declare on the TA6 Property Information form that the property has been affected by Japanese Knotweed.  A professional treatment plan must be in place and secured with an insurance backed guarantee for a minimum of five years, ideally ten. This should prevent difficulties in obtaining a mortgage.

In addition, there is a Japanese Knotweed indemnity insurance policy available for buyers, enabling them to protect themselves. The policy is not expensive and covers treatment costs, repairs and any legal defence expenses.