Permanent burial of Japanese knotweed normally occurs when there is not enough time to treat it with a systemic herbicide. usually, this is due to time constraints from builders, etc. Under these circumstances, removal and excavation is the ideal solution. Once the site has been excavated, it can be issued with a certificate confirming the site to be clear of Japanese knotweed. We use this method when the site needs to be cleared quickly and there is an area that can be excavated where the Japanese Knotweed is and be buried. The benefits are that it keeps dumping costs down, the negative is that the hole is typically 5 plus metres deep and therefore requires large excavators on site.
- Soil will be sifted and the main stand and rhizomes removed.
- The soil is then put into a dumper and this spreads the soil in the hole that has been excavated. It is checked again and any rhizomes missed are removed.
- The root barrier should be UV, animal resistant and guaranteed for 50 years. It needs to be this long because the Japanese knotweed rhizome can remain inactive for up to 20 years. Ideally the sheet is not joined and is one large sheet for the entire area.
- Japanese knotweed can break through concrete so will easily break through seams if not properly jointed, so if two sheets have to be joined, this should be done by a very competent individual.
- If the contaminated soil can’t be buried that deep it can be buried with just 2 metres of uncontaminated soil on top of it. The mound of contaminated soil must be totally encapsulated within the guaranteed membranes.
- Sand or identifying tape should be put on top of the membrane to make it easily identifiable if anyone digs in that area in the future. The idea is that it is buried where the site is being landscaped and trees are planted above the stockpiled Japanese knotweed.
If you are under time constraints and would like to receive more information on how we can move your project along, please contact us, we will be happy to help.