Have you discovered this on your property? Japanese Knotweed is notoriously difficult to remove and it spreads like wildfire. Here's some tips on how to deal with it.
Although rather attractive, Japanese knotweed (Fallopia japonica) is a real thug as it spreads rapidly. In winter the plant dies back beneath ground but by early summer the bamboo-like stems shoot to over 2.1m (7ft), suppressing all other growth. Eradication requires steely determination as it is very hard to remove by hand or with chemicals. New legislation now covers its control .
Japanese knotweed is a strong-growing, clump-forming perennial, with tall, dense annual stems. Stem growth is renewed each year from the stout, deeply-penetrating rhizomes (creeping underground stems).
An amendment to the Anti-social Behaviour, Crime and Policing Act 2014 includes Japanese knotweed and other invasive non-native plants. Full details of how this will work for the homeowner are not yet available, but here are some key points:
It is not illegal to have Japanese knotweed in your garden
On your property, you should aim to control this plant and other invasive non-native plants such as Himalayan balsam and giant hogweed, to prevent them becoming a problem in your neighbourhood. If they have a "detrimental effect of a persistant or continuing nature on the quality of life of those in the locality", the legislation could be used to enforce its control
Control can be carried out by the homeowner (see the control section below) and doesn't require a specialist company. However, a specialist company will be skilled at control and can dispose of the plant waste
Identification is important. Japanese knotweed can be confused with other plants including Persicaria microcephala (e.g. P. microcephala 'Red Dragon'), Leycesteria formosa and Houttuynia cordata
Where problems with Japanese knotweed occur in neighbouring gardens, we suggest that you speak or correspond directly with your neighbours (who may already be taking action to control this difficult weed). These informal steps should be taken before contacting your council to talk about control using the legislation