Invasive Non-Native Species

Over 2,000 non-native plants and animals have been introduced to Britain from all over the world, most are harmless and integrate into the ecosystem. 10-15% of these species spread and become Invasive non-native species (INNS). These species can harm our environment, wildlife and even humans. INNS are one of the top five drivers of biodiversity loss globally, costing Britain’s economy nearly £1.9 billion a year.

Tweed Forum have been tackling several INNS in the Tweed catchment for over 20 years. The Tweed Invasives Project began in 2002 in response to strong public demand to tackle giant hogweed and, since then, it has become one of the largest and most successful of its kind in the UK, covering the entire 5000km2 Tweed catchment.

Invasive Non-Native Species is led by Tweed Forum.

  • Tweed Forum logo
Invasive Non-Native Species
Volunteers from around Peebles help to pull Himalayan Balsam, July 2023.

Species

The project targets five main species as listed below, with more detailed descriptions available on the Tweed Forum website.

 

  • Giant Hogweed

    Giant Hogweed

    Easy to identify when fully grown by height, size of leaves and size of flowers. All parts of the plant contain chemicals called furanocoumarins which pose a risk to human health. When in contact with human skin and in the presence of sunlight, these chemicals cause severe burns and blistering.

  • Japanese Knotweed

    Japanese Knotweed

    Japanese knotweed is a tall herbaceous perennial with bamboo-like stems. Capable of exceptional growth rates and can form dense ‘stands’. This species out-competes native flora and when found in urban areas can grow through concrete and building structures!

  • Himalayan Balsam

    Himalayan Balsam

    Himalayan balsam is a tall, attractive, annual herb with explosive seed heads. Although easy to identify as a mature plant with its pink-purple flowers, fleshy stem and characteristic leaves – the seedlings and last year’s dead stems of this annual are more difficult to spot.

  • American Skunk Cabbage

    American skunk cabbage produces bright yellow flowers in early spring and can reach up to 1.5 m in height. It forms dense stands, in boggy areas, which can smother native vegetation.

  • Pirri-pirri-bur

    Pirri-pirri-bur

    Occurs within a wide range of habitats, including woodlands, shrublands and grasslands, from coastal areas to alpine areas. It grows in freely draining soils such as silty and sandy loams, typically on sites which receive a high amount of sunlight.

Sightings Contact Form

You can play an important part in tackling these invasive plants!

If you see any of these species in the Catchment, please report them to us using this form and include as much information as possible on species type and location.

Visit the Tweed Forum website for more information about the project and the species we aim to tackle.

tweedforum.org