Himalayan balsam: Call the Marines! It’s an alien plant invasion

Scientists, and now the military, are battling the spread of Himalayan balsam

An alien plant, so bothersome that Royal Marines have been called in to try to eradicate it, and so persistent that a top laboratory is working on a biological “secret weapon” to defeat it, has been helped to invade the British countryside by a fifth column of subversive flower lovers.

The Himalayan balsam grows up to 10ft (3m) tall and has colonised large areas beside rivers and woods throughout Britain, smothering any indigenous plants. The Environment Agency, Plantlife, Wildlife Trusts and the National Trust all say the species is a headache, and its total removal could cost as much as £300m.

But, with its pink orchid-like flowers, it is also attractive to many people. It’s so attractive, in fact, that a big factor in its invasive spread is people scattering its seed in the wild, according to research by Professor Ian Rotherham of Sheffield Hallam University and author of Invasive and Introduced Plants and Animals.

He has plotted its spread around the UK, and the novel reasons for it. Himalayan balsam (also known as Indian balsam) was introduced here in 1839 as a greenhouse and warm garden plant and, within a few decades, had escaped into the wild. It gradually established bridgeheads, and then, especially after the Second World War, spread rapidly. Professor Rotherham’s researches show that enthusiasts scattering its seeds far and wide were responsible.

Professor Rotherham’s work, presented to environmental managers some years ago but not to a wider audience, quotes some examples of people who assisted the invader. There was a Miss Welch who, in 1948, collected seeds from Sheffield and took them to the Isle of Wight, where she sprinkled them beside a river near Newport; a Mrs Norris of Camberley in Surrey, who spread them to local waste areas and woods, gave them to passers-by, sent seeds to Ireland and even took them on holiday to France and Spain; plus people who, in recent decades, have carried the species from Norfolk to Newcastle, Aberdeenshire to Leicestershire, Hertfordshire to Essex and Bedfordshire, and Sheffield to the Peak District. Thus, the plant, also known because of the shape of its flowers as “policeman’s helmet”, spread. As Professor Rotherham puts it succinctly: “People like it!”

And once growing, Himalayan balsam can proliferate at a fearsome rate. Each plant produces an average of about 800 seeds, which means that a dense mass of the plants can contain a potential 30,000 seeds per square metre. And the explosive fruit pods can project the seeds several metres. So entertaining can it be to see the pods “pop” that it has even been marketed as a novelty for children – “Mr Noisy’s Exploding Plant” – once sold by, among other outlets, Birmingham Botanical Gardens.

The upshot is that there is barely a part of lowland Britain free of this pretty menace. Fat stands of it clog small streams in places such as Somerset, and mass on the banks of rivers and woods from Cornwall to Scotland, with Norfolk, the Isle of Wight, New Forest, Hampshire, County Durham, Yorkshire, west Cumbria, Lancashire and North and South Wales especially troubled by it. The species is so prolific near Liverpool that it is known there as “Mersey weed”. Himalayan balsam grows in almost impenetrable thickets and will bully out any other species; its plentiful nectar means that bumble bees pollinate it rather than native species, and, being an annual, it dies down, leaving riverbanks bare in winter.

That is why, every summer weekend, conservationists organise clearing parties. This month, Royal Marines from the Commando Training Centre at Lympstone, Devon, joined volunteers to uproot the plants growing beside tributaries of the River Otter. Wildlife Trusts as far apart as North Wales, Surrey and Cambridgeshire are calling up volunteers for anti-balsam efforts, and Professor Rotherham is working with groups on the urban River Don.

But, as fast as it is cleared, it pops up elsewhere. A native of India and Pakistan, it has invaded 23 European countries, New Zealand, the US and Canada. The ecological and financial cost of this is one reason why the laboratories at the Centre for Agricultural Bioscience International (Cabi) in Surrey have been working on a biological solution.

Cabi scientists have discovered a rust fungus which seems to attack only Himalayan balsam and no other plant. If their safety tests find no problems, permission for the controlled release of the rust species will be requested from UK regulators. And, if all else fails, we could always eat it. All parts of the plant are edible, and the seed pods, according to Richard Mabey’s authoritative Flora Britannica, have “a pleasant nutty taste”.

News
Ian Thorpe had Rio 2016 in his sights
people
Sport
world cup 2014A history of the third-place play-offs
News
Tommy Ramone performing at The Old Waldorf Nightclub in 1978 in San Francisco, California.
peopleDrummer Tommy was last surviving member of seminal band
Life and Style
Swimsuit, £245, by Agent Provocateur
fashion

Diving in at the deep end is no excuse for shirking the style stakes

PROMOTED VIDEO
Sport
The Mexico chief finally lets rip as his emotions get the better of him
world cup 2014
Voices
Spectators photograph the Tour de France riders as they make their way through the Yorkshire countryside
voicesHoward Jacobson: Line the streets for a cycling race? You might just as well watch a swarm of wasps
Life and Style
lifeHere's one answer to an inquisitive Reddit user's question
Life and Style
Several male celebrities have confessed to being on a diet, including, from left to right, Hugh Grant, Benedict Cumberbatch and Ryan Reynolds
...and the weight loss industry is rubbing its hands in glee
News
peopleDave Legeno, the actor who played werewolf Fenrir Greyback in the Harry Potter films, has died
Arts and Entertainment
'Eminem's recovery from substance abuse has made him a more potent performer, with physical charisma and energy he never had before'
arts + entsReview: Wembley Stadium ***
News
ebookA unique anthology of reporting and analysis of a crucial period of history
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Information Security Manager (ISO 27001, Accreditation, ITIL)

£70000 per annum: Harrington Starr: Information Security Manager (ISO 27001, A...

C# Developer (HTML5, JavaScript, ASP.NET, Mathematics, Entity)

£30000 - £45000 per annum + Benefits + Bonus: Harrington Starr: C# Developer (...

C# Integration Developer (.NET, Tibco EMS, SQL 2008/2012, XML)

£60000 - £80000 per annum + Benefits + Bonus: Harrington Starr: C# Integration...

Biztalk - outstanding opportunity

£75000 - £85000 per annum + ex bens: Deerfoot IT Resources Limited: Biztalk Te...

Day In a Page

A History of the First World War in 100 Moments: Peace without magnanimity - the summit in a railway siding that ended the fighting

A History of the First World War in 100 Moments

Peace without magnanimity - the summit in a railway siding that ended the fighting
Scottish independence: How the Commonwealth Games could swing the vote

Scottish independence: How the Commonwealth Games could swing the vote

In the final part of our series, Chris Green arrives in Glasgow - a host city struggling to keep the politics out of its celebration of sport
Out in the cold: A writer spends a night on the streets and hears the stories of the homeless

A writer spends a night on the streets

Rough sleepers - the homeless, the destitute and the drunk - exist in every city. Will Nicoll meets those whose luck has run out
Striking new stations, high-speed links and (whisper it) better services - the UK's railways are entering a new golden age

UK's railways are entering a new golden age

New stations are opening across the country and our railways appear to be entering an era not seen in Britain since the early 1950s
Conchita Wurst becomes a 'bride' on the Paris catwalk - and proves there is life after Eurovision

Conchita becomes a 'bride' on Paris catwalk

Alexander Fury salutes the Eurovision Song Contest winner's latest triumph
Pétanque World Championship in Marseilles hit by

Pétanque 'world cup' hit by death threats

This year's most acrimonious sporting event took place in France, not Brazil. How did pétanque get so passionate?
Whelks are healthy, versatile and sustainable - so why did we stop eating them in the UK?

Why did we stop eating whelks?

Whelks were the Victorian equivalent of the donor kebab and our stocks are abundant. So why do we now export them all to the Far East?
10 best women's sunglasses

In the shade: 10 best women's sunglasses

From luxury bespoke eyewear to fun festival sunnies, we round up the shades to be seen in this summer
Germany vs Argentina World Cup 2014: Lionel Messi? Javier Mascherano is key for Argentina...

World Cup final: Messi? Mascherano is key for Argentina...

No 10 is always centre of attention but Barça team-mate is just as crucial to finalists’ hopes
Siobhan-Marie O’Connor: Swimmer knows she needs Glasgow joy on road to Rio

Siobhan-Marie O’Connor: Swimmer needs Glasgow joy on road to Rio

18-year-old says this month’s Commonwealth Games are a key staging post in her career before time slips away
The true Gaza back-story that the Israelis aren’t telling this week

The true Gaza back-story that the Israelis aren’t telling this week

A future Palestine state will have no borders and be an enclave within Israel, surrounded on all sides by Israeli-held territory, says Robert Fisk
A History of the First World War in 100 Moments: The German people demand an end to the fighting

A History of the First World War in 100 Moments

The German people demand an end to the fighting
New play by Oscar Wilde's grandson reveals what the Irish wit said at his trials

New play reveals what Oscar Wilde said at trials

For a century, what Wilde actually said at his trials was a mystery. But the recent discovery of shorthand notes changed that. Now his grandson Merlin Holland has turned them into a play
Can scientists save the world's sea life from

Can scientists save our sea life?

By the end of the century, the only living things left in our oceans could be plankton and jellyfish. Alex Renton meets the scientists who are trying to turn the tide
Richard III, Trafalgar Studios, review: Martin Freeman gives highly intelligent performance

Richard III review

Martin Freeman’s psychotic monarch is big on mockery but wanting in malice