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Dealing with invasive non-native plant species (INNS), and some poisonous plants

An invasive species can be any kind of living plant organism that has been introduced outside its natural range and can cause harm. Landowners have a responsibility to control any invasive weeds. Although it is not a legal obligation, they grow and reproduce quickly.

Some of the most common INNS found in Allerdale include: 

Japanese Knotweed

Japanese Knotweed can damage concrete, tarmac and brickwork and impact on biodiversity. It spreads by underground roots - very small pieces of root can produce new plants.

If you come across Japanese Knotweed growing on public land, you can report it to us online using our general enquiry form.

Himalayan Balsam

Himalayan Balsam is the largest annual plant in Britain, growing up to 2.5m high from seed in a single season. It is particularly common along watercourses and spreads rapidly.

Himalayan Knotweed

Similar to Japanese Knotweed, this INNS is a large, thicket-forming plant, reaching up to 2m tall. It can be found on stream sides, hedge banks, woodland edges, roadsides, railway banks and waste ground.

Giant Hogweed

Giant Hogweed can grow up to 5m tall, and the stem and leaves can cause severe skin irritation and blistering.

Where can I find more information?

Report an invasive species

Poisonous plants

Hemlock Water Dropwort

The plant we get the most requests for information on is Hemlock Water Hogwart . It is often called dead man's fingers, due to the large, cream or pale orange tubers found on beaches and near rivers.

Hemlock Water Dropwort is found growing naturally near ditches and rivers. However, it can find itself being washed down rivers and onto beaches during high rainfall events and flooding. 

Hemlock Water Dropwort is poisonous both to humans and animals.

Therefore we would urge people to be extra vigilant and not to touch these roots if they come across them. We also encourage people to keep dogs and other animals away from it.  If anyone thinks they, or their pet, has been in contact with these roots, they should seek the relevant medical or veterinary advice.

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Cumberland Council

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