Burying invasive weeds and contaminated soil on-site

Taking contaminated soil and plant material away for disposal off-site uses valuable landfill capacity and increases the likelihood of the spread of invasive weeds. Another option is to bury contaminated soil and plant material on your own land because without sunlight, plants cannot survive and seeds will not germinate.

Be aware that this material will need to remain buried for several years to ensure that it will not grow again. Giant hogweed seeds can be viable for up to 15 years.

What you must do

First, speak to your environmental regulator about using this option in your location. Your environmental regulator may want to look at the site and may visit while the works are undertaken.

Contaminated soil and plant material need to be buried at least 5m below ground level. You should place a barrier membrane on top of the contaminated material and fill the hole with clean soil.

You must not bury anything other than invasive weed contaminated soil and plant material.

If you have previously treated the invasive weeds with a herbicide that does not break down in the environment, burying contaminated soil and plant material could cause groundwater pollution. Check with your environmental regulator.

Herbicides that do not break down in the environment are described as ‘persistent’. Those that do break down are described as biodegradable. You will find this information on the herbicide packaging or on the material safety data sheet.

In addition to the information above, you need to undertake the same actions as you would for digging up plants and spraying them with herbicide.

Good practice

Make sure you keep records of the quantity of material that you have buried.

Keep a map showing the location of the burial pit and its depth.

In this guideline: