Invasive plants are usually non-native species that spread out of control.

They cause problems to us because the pests and diseases that stop them spreading in their countries of origin are not present in the UK.

They can cause environmental problems such as:

  • suffocating other plant life
  • being poisonous to animals
  • damaging buildings as they grow

You can find out more on RHS’s invasive plants page.

How to report invasive plants

You can report invasive plants in South Gloucestershire to us.

If the invasive plant is:

If we are responsible for the land where the invasive plant is growing we will deal with them.

If the plant is on private land we may ask the landowner to deal with it to stop it spreading.

You should seek specialist advice for invasive plants on your own land and get rid of them quickly and safely. Invasive plants should not be composted or added to waste collections.

It is illegal to plant invasive plants or cause them to spread in any way.

Types of invasive plants

Common ragwort

This is a native plant that grows up to one metre tall.

It has a large, densely packed head of bright yellow flowers.

It is very poisonous to horses, cattle and other animals so must be kept away from agricultural land. It can also be toxic to humans and you must avoid touching it.

Ragwort is subject to the Weeds Act of 1959 so landowners can be served with enforcement notices where necessary to make sure they stop it from spreading.

Closeup of yellow blooming wild flowers in their own habitat. It is a sunny day in the summer season.

Japanese knotweed

This is a plant that forms dense stands of tall, hollow, speckled canes during summer which die back in autumn.

During spring, reddish purple shoots appear and the plant grows rapidly. As leaves open up, the plant turns green.

It can grow up to three metres tall.

Knotweed can damage hard surfaces like tarmac or floors of houses as it grows.

It is best to deal with it while it is still small.

Knotweed on council land

If Japanese Knotweed is found on council land, we will treat it chemically between May and October each year.

We only treat Japanese knotweed between these months as this is when the weed is most receptive to treatment but we will take reports throughout the year.

The treatment process can take 3 to 4 years to be successful.

Knotweed on private land

There are 2 main ways of treating Japanese knotweed in your garden.

Chemical controls: The plant is resilient to cutting and sprouts from the roots. The most effective method of control is by herbicide application close to the flowering stage in late summer or autumn.

Non-chemical controls: Digging out is possible but due to the depth that the roots can penetrate, regrowth usually occurs. Try and remove as much of the root as possible then repeatedly destroy any regrowth. It will need drying out before burning.

Anyone burying Japanese knotweed waste should inform the Environment Agency at least 1 week before by calling 0370 850 6506.

Japanese knotweed cannot be disposed of in your rubbish or garden waste bin.

Large leaves with white yellow flowers.

Giant hogweed

This plant can grow up to 7 metres tall. It looks like a larger version of common hogweed or cow parsley.

It has sturdy, dark reddish-purple stems and spotted leaf stalks that are hollow and produce thick bristles.

It flowers from May to July with white flowers clustered into an umbrella head that can be up to 80cm across. Giant hogweed can cause severe blisters on your skin. If you touch it wash the area immediately.

Early spring hogweed plant green with white blossom on grass.

Himalayan balsam

This is a herb that can grow up to 2 metres tall. It has upright, purple-tinged stems and white, pink or purple flowers that appear from July to October. It spreads very quickly, particularly along riverbanks or in wetlands.

Small purple flowers on a brown stem with a leafy background.

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