Japanese knotweed identification - what does it look like?

We've produced a free Japanese Knotweed Identification Guide for Surveyors - click here for your free copy. 

Japanese knotweed is usually fairly distinctive as it is a tall (2-3m high) plant. However, being perennial it appearance changes with the seasons, starting with new shoots in spring, growing to its full height by July. It flowers in August or September before dying back in November leaving brittle leafless canes in winter, making it more difficult to identify.

The appearance of the plant can be substantially altered by application of certain herbicides, making the identification of Japanese knotweed more difficult to the untrained eye. Where these have not been completely effective the knotweed re-growth returns with stunted plants, not exceeding waist height, with small leaves and spindly stems.