It is well known among the botanists that the Japanese knotweed is more than a gigantic plant that grows wide and deep. It is considered a giant herbaceous perennial weed that can spike to 10cm per day in almost any soil. As a native in Asia, the Japanese knotweed thrives on almost any type of soil including waste ground. Japanese Knotweed Expert Ltd say it was originally thriving on volcanic slopes; its natural habitat. Bugs in Asia kept the wild spread of this plant under control but there is hardly any such predator in the US or Europe which allows this plant to have a field day.
Handling this new and insidious invasion of Japanese Knotweed has become a matter of concern across the British countryside and urban centers and suburbs. This fast-growing, hardy weed which was once cultivated by Victorians as an ornamental plant in the 19th century has mutated into a scourge that attacks old and new buildings from the foundations, waterways, drainage systems, motorways, roads, and airport tarmac.
Knotweed infestation, apart from causing destruction, can also bring down property values of commercial and residential land, and make property owners and tenants liable to criminal and civil prosecution under several environmental protection and civic liability acts. Getting rid of this urban nightmare has become a priority. However, many horticultural experts feel that the situation has been unnecessarily vitiated by the efforts of a few mortgage and realty companies who started the ball rolling by refusing to lend on Knotweed infested properties. They feel that Knotweed, while it can cause structural damage, is not as catastrophic as it’s made out to be. With timely intervention, Knotweed can be eradicated quite effectively.
Today several companies offer a suite of services to help eradicate/control Knotweed and it’s essential to keep some pointers in mind when choosing the right one for your needs.
Survey Services: Before investing in land or selling it, you can employ a surveyor to assess the property thoroughly and provide a detailed report of not only the condition of your property but also that of neighbouring areas if you suspect that Knotweed penetration may be present underground. The RICS (Royal Institution of Chartered Surveyors, UK) is planning to bring out a study to help its surveyors to assess Knotweed infestation risks and provide a balanced and practical assessment of the risks.
Eradication or Control: Different strategies have to be followed for both. Most property-owners prefer complete eradication though it takes time, effort and money. However, for special situations like Knotweed in a waterway system, only control may be possible.
Chemical or Organic: herbicides are available for clients to choose from. Alternate treatments like vinegar and sea-water sprays have been found effective in smaller plots/weaker infestation.
Removal: is considered the best type of eradication, but also the most rigorous and laborious. Large tracts of earth have to be dug, as Knotweed is known to penetrate up to 10 meters and even the trace of a stem or rhizome left behind can lead to re-infection. The problem with removal is that the moved earth must be disposed of properly, otherwise it can contaminate water-systems and neighbouring property.
Root-barrier, Cell-burial and Quarantining: are methods which must be conducted under strict supervision, since they are control rather than eradication methods. Frequent assessment of the restrictive barriers has to be undertaken by soil and horticultural experts.
Finally, taking proper preventive steps would be the best solution rather than attempting to eradicate or control it.