Japanese knotweed is a vigorous and invasive plant that spreads rapidly. It can cause damage to buildings, paths and roads as it is capably of breaking through concrete.
If you think you have Japanese knotweed on your property or on Council land next to your property don’t worry. It is treatable.
It’s easy to identify knotweed as it’s very distinctive. If the plant looks like the photos below it’s knotweed.
The wildlife and Countryside Act 1981 says:
- it is an offence to plant or otherwise cause Japanese knotweed to grow in the wild.
This means that all Japanese knotweed should be subject to treatment to kill it. You can be fined or prosecuted for allowing the plant to grow or spread.
We treat knotweed on our land each September and October with our annual spraying programme. We will continue to treat any re-growth of knotweed on an annual basis until the roots have been killed. This can take several years.
The Council does not dig up knotweed as a treatment method and we don’t treat knotweed on private land.
The best way to treat knotweed is to spray the foliage with a glyphosate based weed killer. Burning the shoots with a weed burner will not kill the roots.
Most weed killers bought in DIY stores and garden centres contain glyphosate.
Always follow the instruction on the product and ensure any foliage is well sprayed. Continue to spray emergence of foliage throughout the year.
There are private companies which can contracted to treat your knotweed. Details are available through an internet search.
Knotweed can lay dormant in the soil for several years.
It is best to avoid disturbance of the area for a few years. If you disturb the area the plant my re-activate. Ensure you wash and disinfectant any tools used to dig in the area.
If the plant re-emerges continue to spray with weed killer.
In winter the plants stems will go brown. At this time of year you can cut the stems off. It is best to do this in February to make sure all stems are dead.
You can either burn the stems or wrap them in thick polythene to rot down. Do not allow any part of the stem to touch the soil as can regrow if not totally dead.
Where material has been burnt spread the ashes back on the area of land affected by knotweed. This ensures that if any viable material remains you are not spreading the plant.
Do not place any part of the plant dead or alive in the garden waste bin or compost heap.
Do not take the plant material dead or alive to the Household Waste Site as this is illegal.
It is illegal to move Japanese Knotweed off site unless you have a special licence.
Do not put any plant material into the garden waste bin as you would be committing an offence.
Don’t take it to the household waste site.
The best way to dispose of the plant material whether dead or alive is to burn the material in a garden incinerator. These can be purchased from DIY and garden centres and look like a metal bin with holes in.
This ensures the fire is hot enough to destroy all material.
No don’t dig it up.
Knotweed can regenerate from very small pieces of live stem or roots left in the ground or on tools so you could easily cause the plant to spread.
Soil within seven meters of a visible shoot and up to 2 metres can contain knotweed roots.
Last updated: 18/08/2022 10:00