Preventing The Spread Of Japanese Knotweed

Unfortunately, preventing the spread of Japanese Knotweed is not an easy task.

In the UK, research has shown that it is very rare for a female plant to produce fertile seeds, meaning Japanese Knotweed cannot spread using viable seeds. As a result, the key to its prevention is the destruction of the rhizome - an underground root system that grows horizontally in the soil, giving rise to the stems that emerge above ground. This means that a course of localised treatment over a number of years can effectively remove the plant permanently.

With its incredible ability to grow in the harshest conditions, Japanese Knotweed must be managed effectively if ever located within your garden. Attempting to remove the plant yourself can cause more harm than good, as digging is known to increase stem density over time as the plant reacts to your attack. Calling in the professionals like WWCS is always the best policy in this circumstance, as our team have the knowledge and experience to be able to treat any amount of Japanese Knotweed efficiently.

Preventing the spead and treatments

The key to preventing further spread of the plant is close control of any cuttings or pulled stems, as these can re-grow easily if disposed of incorrectly. As Japanese Knotweed is listed under the Wildlife and Countryside Act 1981, allowing the spread of the plant into the wild is considered an offence and you can potentially be prosecuted. If you are going to attempt any plant removal yourself (which we would not advise), thoroughly burning the plant material on site is the only realistic way of ensuring no regrowth can occur.

There are a number of chemical treatments that can be applied to control the spread of Japanese Knotweed, and these are considered by many to be the most effective treatment methods. The plants should be sprayed with the herbicide when they are short, for example in the spring when the shoots have just appeared or after cutting. Treating the plants during March and October attacks them in their growing phase meaning the herbicide should be most effective, but it can take up to six weeks before any sign of die-back is obvious.

Non-chemical treatments are available, but are less effective and require more labour over a number of years. Cutting, mowing or pulling are all methods of controlling the plants, but only if they are carried out regularly. Cutting and mowing in particular are good ways of preventing the spread of the Japanese Knotweed, but they should be used in tandem with a chemical treatment to ensure die-back.

If you would like further information regarding the control of Japanese Knotweed, contact WWCS today and speak to one of our expert team members.