UK Government

Department for Environment Food and Rural Affairs: Weeding out of water invaders

Press Release   •   Feb 24, 2010 11:29 GMT

Defra calls on the nation’s gardeners to help stop the spread of invasive plants

Defra and the Scottish Government today (Wednesday 24 February) called on Britain’s gardeners to help stop the spread of invasive aquatic plants that damage the natural environment and cost the economy millions with a new campaign to highlight the plight of Britain’s waterways.

The Be Plant Wise campaign highlights five of the worst offenders currently wreaking havoc on our wildlife and waterways. Gardeners can often unwittingly exacerbate the problem by disposing of unwanted pond plants without composting them properly, throwing out pond water or fish tank water incorrectly, or accidentally introducing species to the wild. A whole river can be strangled just from one fragment of plant. Fast-growing floating pennywort, New Zealand pigmyweed, water-primrose, parrot’s feather and water fern – all of which could be found in your garden pond - are some of those named as posing significant problems in the wild with the potential to cost the nation millions of pounds if they continue to expand at their current rate. Floating pennywort can grow at a rate of 20cm a day in the wild and water primrose can double in size every 15-20 days. Many of these plants grow to such an extent that they form dense mats which can look like dry land and so pose an additional danger of drowning to people and livestock.

Natural Environment Minister Huw Irranca-Davies launched the new public campaign with the support of celebrated gardener, Charlie Dimmock, from the banks of the River Wandle, London which is overrun by floating pennywort.

The Minister said: “From the River Severn to the smallest stream, our waterways are being invaded. We all know about grey squirrels and Japanese knotweed but how many people know that invasive aquatic plants can out-compete native species, choke waterways, harm native wildlife, disrupt the navigation of boats, interfere with recreational activities such as fishing and boating and exacerbate flooding?

"Gardeners can do their bit to help stop the spread by knowing what they grow in their ponds and disposing of unwanted plants with the utmost care. I’m really pleased that many retailers are already taking steps to ensure people know what they’re buying and advising customers on how to dispose of plants properly. This is vital to halt the spread and prevent our waterways from getting overrun.”

The problem is already affecting many major landmarks including: the New Forest in Hampshire; the River Soar in East Midlands; Richmond Park in London; Roadford Lake in Devon (where water sports have come to a stop given the huge spread of New Zealand pigmyweed); and Horsepond in Corfe Castle, Dorset (a SSSI owned by National Trust where the Trust believes New Zealand pigmyweed has meant the loss of the great crested newt in that area).

The sheer scale of the problem threatening Britain’s waterways, wildlife, leisure activities, farming and tourism can be seen in France where water-primrose is known to be present in over 500 sites, and is the most recent invasive plant to reach Britain’s shores. Across France, control costs run into several million € a year just to limit its negative impacts, not to get rid of it completely.

Charlie Dimmock, championing the campaign for gardeners enthused: “Ponds and rivers give us a bounty of amazing wildlife, but sometimes the balance can be upset, harming our natural biodiversity. Pond-lovers, like me, must all play our part in making sure invasive aquatic plants don’t cause serious damage to our beautiful waterways. By being plant wise in our gardens we can help protect natural habitats in the wild and ensure all ponds and rivers thrive.”

Pond owners are advised to:

*Know what you grow – pick the right plants for your pond and manage them carefully. Choose non-invasive species where possible;

*Stop the spread – be careful not to introduce invasive species into the wild, even accidentally, as you could be breaking the law;

*Compost with care – make sure you dispose of the whole plant properly and no fragments break away; dispose of waste pond and fish tank water away from streams, rivers, ponds or lakes;

Visit for more information in England, or in Scotland visit

As part of the United Nations-designated International Year of Biodiversity the Be Plant Wise campaign will help encourage people to take care with their pond plants, to know what ponds plants they might have in their pond and the issues associated with them, and to dispose of all unwanted pond plants carefully and prevent any from escaping into the wild.

Go to to find out more about the campaign and learn how to spot and manage invasive aquatic plants.

In Scotland visit for more information

For more information, images, interviews and footage:

Katie McCrory, Lisa Mangan or Jacqueline Culleton at Forster
T: 020 7403 2230
E: / /

Notes for editors

*Images of all five invasive aquatic plants, photos of Charlie Dimmock, footage of Charlie Dimmock giving garden-based advice and a map of affected areas in the UK are all available upon request. Also available are key facts on the five named invasive aquatic species.

*The campaign has the support of major bodies, environmental charities and agencies including: the Ornamental Aquatic Trade Association, the Horticultural Trade Association, British Waterways, the National Trust, the Environment Agency, Plantlife and Pond Conservation. The Government is also working closely with retailers of aquatic plants to provide information in stores.

*Charlie Dimmock is one of Britain's best known and best loved gardeners, specialising in water features. Having first come to the nation's attention on BBC1's popular Ground Force, Charlie has gone on to present amongst other things, Cheer for Charlie, Charlie and the Duchess, Garden Invaders and Chelsea Flower Show, all BBC. Her books include Enjoy Your Garden and Container Gardening. You can watch her Be Plant Wise campaign video at

*Defra is the Government Department for Environment, Food and Rural Affairs. It helps people adapt to the changes involved in building a low-carbon, resource-efficient economy. Defra deals with environmental risks and works towards securing a sustainable society and a healthy environment in which we and future generations can prosper.

*The Be Plant Wise campaign, launched by Defra and the Scottish Government is designed to raise awareness among gardeners, pond owners and retailers of the damage caused by invasive aquatic plants and to encourage the public to dispose of these plants correctly.

*Be Plant Wise is part of the world-wide celebrations of 2010 as the International Year of Biodiversity. The diversity of life on earth is crucial for human well-being and now is the time to act to preserve it. For information on International Year of Biodiversity events, initiatives and exhibitions across the UK visit


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