There are several hundred invasive plants in the UK. Japanese knotweed and Himalayan balsam are invasive plants that you might come into contact with.
You must not plant invasive plants intentionally and if you have invasive plants on your property you must not allow them to spread off site.
Invasive non-native plants can cause problems for native UK species and reduce biodiversity (the variety of living organisms). Invasive non-native species are now widely recognised as the second biggest threat to biodiversity worldwide.
Japanese knotweed can block footpaths and damage concrete, tarmac, flood defences and the stability of river banks. Giant hogweed can cause harm to human health.
Injurious weeds are native species, which cause problems for farming. They are harmful to livestock and must not be allowed to spread to agricultural land.
Follow this link to find out more - a summary is below:
Common name Japanese knotweed
Latin name Fallopia japonica (syn. Polygonum cuspidatum)
Areas affected Waysides, beds, borders and paving
Main causes Weed with creeping roots
Timing Seen late spring to autumn; treat in summer
Japanese knotweed was introduced from Japan in 1825 as an ornamental plant. The plant is not unattractive but its rapid annual growth and relentless spread, allows it to easily overwhelm other garden plants. Where established as a wayside weed, native plants are also aggressively over-run.
Although it does not produce seeds, it can sprout from very small sections of rhizomes and, under the provisions made within the Wildlife and Countryside Act 1981, it is an offence to cause Japanese knotweed to grow in the wild. Much of its spread is probably via topsoil movement or construction traffic.