This non-native plant is extremely invasive and difficult to eradicate. At one time the Ham Lands were severely affected by many large, dense stands of it. The Council mounted a major eradication programmed in the 1990s. Thankfully this highly expensive venture was a great success. However, a few small clumps have now reestablished and will need specialist treatment. The law says - you must not cause Japanese knotweed to grow in the wild. Not only will Japanese knotweed spread by its highly vigorous root system, but it can regenerate from stem fragments. Fortunately, only one clone of female plants was introduced in the UK, so distribution by seed does not occur. Hybrids with other species have been recorded but are infrequent.
If you do see any Japanese knotweed plants please do not try to remove them or break bits off; instead please report the occurrence to us so that it can be professionally eradicated.
Please look at the individual picture for more information how to regonize the knotweed.