New Forest Non-Native Plants Project

Catherine Chatters at the New Forest Show

The New Forest Non-Native Plants Project was established in May 2009 to stop the spread of invasive non-native plants in the New Forest area, particularly in wetland habitats and along rivers and streams. The Project is hosted by the Hampshire and Isle of Wight Wildlife Trust and funding has been provided by a partnership of organisations involving the Environment Agency, Forestry Commission, Defra, Natural England, The New Forest Trust and the New Forest National Park Authority. Species being tackled by the Project include Himalayan Balsam, Japanese Knotweed, Giant Hogweed, Parrot’s Feather, Creeping Water-primrose, New Zealand Pygmyweed, American Skunk Cabbage, Himalayan Knotweed, Pitcher Plant, Montbretia, Bog Arum and Iris laevigata.


The Project aims to:

  • identify where these plants are a problem;
  • arrange for control work to be carried out by volunteers and contractors;
  • commission research into control methods;
  • raise awareness of the need to control these plants and to prevent them spreading into our countryside.


The Project Officers help to implement, at the local level, the Invasive Non-Native Species Framework Strategy for Great Britain and the government’s Be Plant Wise campaign. The Project’s success is dependent on a strong partnership approach with landowners, volunteers, contractors, universities, the media and the general public.


In 2012, the New Forest Non-Native Plants Project commissioned research on the impact of American skunk cabbage Lysichiton americanus on native vegetation. Click here to view the final report.

The New Forest Non-native Plants Project also undertook a three year trial to assess the effectiveness of hot foam, aquatic dye and herbicide to control New Zealand pygmyweed Crassula helmsii without having a long-term detrimental impact on native non-target species (plants and invertebrates). The results of the trials were monitored by Dr Naomi Ewald of Freshwater Habitats Trust. Download the final report and annex report.

As a partner in the Reducing the Impact of Non-native Species in Europe (RINSE) project, the following documents were prepared on behalf of the New Forest Non-native Plants Project.

RINSE Partner Annex report - Crassula helmsii in the New Forest - a report on the status spread and impact of this non-native invasive plant and the efficacy of control techniques following a 2 year trial

Control of creeping water primrose Ludwigia grandiflora at Breamore Marsh, in New Forest District, Hampshire, UK

Control of giant hogweed Heracleaum mantegazzianum along the Avon Water in the New Forest, Hampshire, UK

Mobilising volunteers to control Himalayan balsam across river catchments

On Wednesday 20 March 2013, the New Forest Non-Native Plants Project hosted a one-day conference on New Zealand pygmyweed Crassula helmsii. This was an opportunity for land owners, land managers, naturalists and ecologists to share experience and to find out about a wide range of control techniques which have been tried in the UK and elsewhere in Europe. The RINSE (Reducing the Impact of Invasive Species in Europe) Project provided financial support for this event.

Link to the event programme

Thin strip of image show tree trunk and bark