Invasive Species Week

You can pledge your support during Invasive Species Week to help protect native species from threats such as Japanese Knotweed and Himalayan balsam

Friday 23 March to Thursday 29 March 2018 has been designated as Invasive Species Week to highlight the problems caused by invasive non-native species.

For example, plants such as Japanese knotweed, Himalayan balsam and giant hogweed were introduced as ornamentals in the Victorian era but have ‘jumped the garden fence’, threatening our native wildlife and causing economic and social problems.

Japanese knotweed is notorious for causing structural damage to property and giant hogweed has a toxic sap which can cause painful ‘burning’ blisters on people’s skin, whilst Himalayan balsam can grow in dense patches out-competing native wildflowers.

To help landowners meet their responsibilities to stop the spread of invasive non-native species, Local Action Groups have been set up in many parts of the country.

The New Forest Non-Native Plants Project (NFNNPP) is the ‘local action group’ which works closely with landowners and land managers to control invasive non-native plants in the New Forest, particularly along watercourses and in wetland habitats. The Project is hosted by Hampshire & Isle of Wight Wildlife Trust and supported by a range of partner organisations.

Volunteer work party pulling Himalayan balsam

Since I started work as The New Forest Non-Native Plants Officer nine years ago, I have helped landowners tackle about two dozen different types of invasive non-native plants. Sometimes I commission professional contractors to control the plants using approved herbicides and sometimes I have help from the wonderful people who give up their time to volunteer for the Project.

Volunteers help the NFNNPP in all sorts of ways from surveying the distribution of Cotoneaster on former wartime airfields in the New Forest, to digging up Pitcher Plants which have become established in species-rich, ecologically important wetlands.

However, the main way in which people help our Project is by getting involved in volunteer work parties to pull up Himalayan balsam.

Introduced in the nineteenth century as a garden plant, Himalayan balsam has spread rapidly and invaded the countryside, particularly along river banks, where it can form dense colonies and out-compete our native wildlife. Its seed pods ‘explode’ quite dramatically when ripe, scattering the seeds over a wide area and, although it’s an annual plant, it can reach an astounding five metres in height by mid-summer.

Himalayan balsam

Himalayan balsam © Lianne de Mello

Fortunately Himalayan balsam has short roots and can be pulled up easily, so Himalayan balsam-pulling can be very satisfying. You can quickly see that you’ve made a difference. People enjoy coming on balsam pulls as it’s a chance to spend time outdoors in the company of like-minded people and it’s often an opportunity to explore parts of the countryside that aren’t usually accessible to the public.

Many of our volunteers come out each week during the summer, some people just come for a few sessions and others come as part of a corporate group or a youth organisation. During 2017 we welcomed local Guides and Scouts and had help from people working for a wide range of businesses including Southern Water, Old Mutual and HSBC. Last year between mid May and early October 337 individual people volunteered on Himalayan balsam pulls with the NFNNPP, generously giving 3,288 hours of their time.

I am incredibly grateful for the huge amount of help given by the amazing people who volunteer with the NFNNPP and am very much looking forward to leading more Himalayan balsam pulls this summer.

If you have a bit of time to spare and are interested in getting involved with a Local Action Group, why not pledge your support during Invasive Species Week? To find out if there is a Local Action Group in your area, have a look at the Local Action Group section of the Great Britain Non-native Species Secretariat’s website at