Japanese knotweed is an invasive non-native plant that can cause significant damage to property and the environment. It can smother and take over adjacent areas, blocking sunlight and restricting access to buildings and roads. This can result in serious structural damage and a loss of value to properties and land. It can also pose a threat to wildlife habitats, water courses and drainage systems. It can be extremely difficult to identify at ground level, especially during the winter. However, if you know what to look for, it can be easier to recognise japanese knotweed.
In spring, the first tell-tale signs of a knotweed are crimson pink buds that break out from a rhizome near the surface of the ground. From this point, the plant grows extremely rapidly. As the shoots develop, they grow to be up to 2.1m (7ft) tall with bamboo-like canes and green leaves that are heart or shovel-shaped, up to 14cm (5 1/2in) long and arranged in a zig-zag pattern along the stems.
The stems of a knotweed plant are hollow and segmented, like bamboo, but with distinctive purple/red speckling. They have a tussock-like appearance and are generally quite thin. As the stems mature, they form a dense, imposing vegetative mass that can grow to heights of up to 3 metres.
During the summer, how to recognise japanese knotweed produces clusters of white flowers that resemble miniature cauliflower heads. They are one of the most distinctive features that help to distinguish knotweed from other plants. Until they are fully mature, the flowers can be easily mistaken for common bindweed, dogwood, dock, Himalayan honeysuckle, and lilac.
If you are concerned that you may have spotted Japanese knotweed, the most important thing to bear in mind is that the plant will not go away on its own. It requires professional intervention to ensure it is dealt with quickly and effectively. This will most likely involve the use of herbicides to remove it.
This is only effective when used in accordance with the manufacturer’s instructions and in line with environmental legislation. For this reason, it is essential that you contact a recognised invasive weed control expert to carry out a survey of your site before beginning treatment.
Despite being one of the most difficult and hazardous invasive weeds to identify, Japanese knotweed is actually fairly easy to spot when you know what to look for. By understanding what to look for, you can avoid mistaking it for other plants and causing costly damage to your property. For further information on how to recognise knotweed or if you have spotted any on your property, speak to a JBB Knotweed specialist for a professional survey.