The Invasive Plant Company can provide a third party insurance backed guarantee for all of our works/treatment methods. Insurance terms are based on a 5 or 10 year period.

Also known by its Latin name of Fallopia japonica Japanese Knotweed is a non-native species that was imported into the UK by the Victorians as an ornamental plant. However, without its native predators and in more favourable conditions it has been able to spread relatively unchecked and now colonises large areas of the UK on mainly brownfield sites, railway and river corridors.

Japanese Knotweed can spread rapidly and has the ability to exploit gaps in concrete, tarmac and other construction materials. This can severely weaken surrounding structures and acting early can dramatically reduce costs treatment and eradication in the long run.

For more photos of Japanese Knotweed please see the Japanese Knotweed Pictures Gallery.

The presence of Japanese Knotweed on a site can reduce its land value if it is being sold or developed. Further more most local authorities make the treatment of japanese knotweed a condition of planning. By acting early the options for Japanese Knotweed eradication are increased allowing for more choice regarding available methods and cost. If the remediation method is taken into account at conceptual stage some of the suggested requirements, for example a landscaped area to cover on-site burial, can be factored into the design at little or no extra cost to the whole process.

By providing a comprehensive method of Japanese Knotweed control with the planning application also reduces the chance of delays at this stage.

-|Back to the top|-

The most effective herbicide used in Japanese Knotweed eradication is semi-persistent and can remain in the soil for up to two years and would adversely affect any broadleaf species planted in the soil. With this in mind when using herbicides to treat the Japanese Knotweed on site it is recommended against using the soil in landscaped areas. However, if when excavated, the viable rhizomes are removed from the soil this can then be buried on site under 1m of capping or a membrane.

-|Back to the top|-

Using herbicides to eradicate Japanese Knotweed can often be the most cost effective method of treatment. However, this does take up to four years to be fully effective, and even then there should be caution if the land is disturbed. This is because our evidence shows that when applying herbicides in several applications over a four year period the persistent nature of the herbicide remains in the soil to curb future growth. Disturbing the soil, and the Knotweed, could stimulate the further growth in areas where the herbicide had not penetrated.

The issue relates to the Knotweed being able to spread from vegetative regeneration. When herbicides are used not all of the rhizome is killed and what is not killed, usually the knotweed at a greater depth, is able to not only remain alive but sprout new growth and attempt to reach the surface to get the sunlight needed to photosynthesise. This process can take over a year.

-|Back to the top|-