It is an offence to allow Japanese Knotweed to spread across neighbouring land and is therefore best treated as soon as it is identified. Ideally it should be treated during early and late Summer with the dead stems (above ground growth) removed in the Winter. However, standard advice is to treat Japanese Knotweed as soon as it is identified.
Treatment for management or eradication
Removal of Japanese Knotweed by attempting to dig it out is usually impractical and costly because it is so invasive and spreads widely. A 25mm length of root left in the ground is sufficient for the plant to regrow. When the first frost comes the leaves and stems above ground will die but untreated plants will continue to live underground ready to sprout new growth in the following Spring.
The preferred method of treatment is with the herbicide Glyphosate. A retail version of this chemical is available to the general public but its low strength means treatment is a long-term solution and can take up to five years of continued treatment to completely eradicate the weed.
Clearway’s operatives are qualified and accredited to use undiluted industrial strength Glyphosate. This is injected directly into each stem (stem injection) for larger plants and sprayed onto smaller plants (foliage spray). If spraying is not suitable for a given area we are also able to provide removal by excavation.
Stem injection can be used in all weathers and eradication can sometimes be achieved in two seasons.
After each treatment is complete the property owner or tenant will be advised not to touch the Japanese Knotweed plants and not to walk on or dig soil in the vicinity.
Japanese knotweed is classified as controlled waste under the Environmental Protection Act 1990 and must be disposed of according to current legislation. We are accredited to remove and dispose of Japanese Knotweed.
On most occasions our treatment process results in complete eradication but Japanese Knotweed is extremely aggressive and can be resistant to treatment. An ongoing programme of treatment to manage Japanese Knotweed is therefore highly recommended as growth can return from the roots of a plant in a neighbouring garden.