Himalayan Balsam - Where It Came From & How It Got Here

In 1937 the climber, explorer and plantsman F.S. Smythe travelled to the remote Bhyundar Valley in the (then) British Protectorate of Sikkim in the Himalayas. In the course of his expedition he noted that, “... where extensive grazing is permitted, the smaller and tenderer plants are soon eliminated and in their place spring up a tall knotweed (Polygonum polystachyum) and an even taller balsam (Impatiens Roylei). Once these two plants have got a hold of the ground, pastureland is permanently ruined and I noticed a number of places in the Bhyundar Valley where this had occurred.”

Those parts of the valley that were not over-grazed were smothered in wonderful displays of wild flowers: Androsaces, Saxifrages, Sedums, Potentillas, Geums, Asters, Gentians and many more.

Polygonum polystachyum, now called Persicaria wallichii, is Himalayan Knotweed; it does occur in Britain, as a garden escape, but doesn’t appear to be particularly common (yet!) but in many American states it’s classified as a pernicious weed.  Its close relative, Fallopia japonica – Japanese Knotweed is a pernicious weed in this country and has a fearsome reputation for being hard to eliminate. 

Impatiens Roylei, now called Impatiens glandulifera, is Himalayan Balsam. It is just as invasive in Britain as it is in its homeland (of Northern India), and probably even more so because here it doesn’t require overgrazing in order for it to take a hold. It is now found all over Britain, along rivers, streams and canals and in damp places and on waste ground.  Whereas the two Knotweeds described above are perennials with extensive and invasive rootstocks, Himalayan Balsam is an annual which regenerates every year by seed. It is reckoned that its seeds can remain viable in the ground for around two years. Once this plant’s long, tear-dropped shaped seed pods are ripe, in late summer, they explode at the slightest touch and fling out seeds with such force that they can travel many yards from the parent plant.

On the Chorlton Ees and Ivy Green Local Nature Reserve Himalayan Balsam is found in abundance along the banks of Chorlton Brook, where the seeds have probably been deposited on the banks following floods. The exploding seed pod mechanism has then allowed the plants to spread out sideways and beyond the confines of the brook’s banks.

The Sunday before last (01.07.2012) members of FoCM attempted to remove as much Balsam as possible from the edge of a small Birch and Willow copse. We chose this site because the copse provides a habitat for a rather scarce species of fern called Narrow Buckler Fern (Dryopteris carthusiana), which we believe it is important to conserve.

So how did I. glandulifera get to the UK and become so invasive? This turns out to be a rather surprising story. It was first introduced into the UK in 1839, when Dr John Forbes Royle, an Indian born British botanist, sent seeds to Kew. By 1855 it was first found growing wild in Hertfordshire and Middlesex. The Manchester botanist, Leo Grindon mentioned it in his ‘Manchester Flora’ of 1859: “The Impatiens coccinea (sic), a tall and weedy plant, with flowers of a dull red colour, is rapidly disseminating itself ...” (I’m not sure where Grindon got that name – but it’s almost certainly yet another defunct synonym for I. glandulifera – and there’s really nothing else that it could be).  So rapidly did Himalayan Balsam ‘disseminate’ itself that by 1932 it was found in 27 out of 112 British Vice Counties (for the purposes of biological recording Britain is divided into standard, approximately equal area zones called ‘Vice Counties’); by 1962 it was found in 47 VCs and by 1993 it was found in 107. This relentless spread was probably due to the fact that the species proved to be very attractive to gardeners - who saw it as exotic looking, attractive and easy to grow (surely, a monumental understatement!).

 During the course of the 19^th century the influential gardener, William Robinson developed his concept of the ‘Wild Garden’. This was, basically, a reaction against Victorian regimented bedding schemes. Robinson was aiming for as ‘natural’ a looking garden as possible. This was mainly an aesthetic concept, and had little to do with wildlife or ecology. In his planting schemes he used many of the plant species that were pouring into Britain from the temperate parts of the world. Among the species that he selected were such ‘horrors’ as Giant Hogweed, Japanese Knotweed and – you guessed it – Himalayan Balsam; and we’re still living with the consequences!

But we can’t blame Robinson alone.  In 2000 Ian D. Rotherham, of Sheffield Hallam University, presented a paper on the spread of Himalayan Balsam to a conference on Ecology in Birmingham. Rotherham, and his colleagues, had initiated a study of the spread of the plant – first in the Sheffield area – and then in the rest of the UK. They published a request for information, from members of the public, in the local and national media (mainly gardening magazines). They received over 200 replies. It became obvious that many people like this plant – and have deliberately spread it! For example:

In 1948 Miss Welch collected seed near Sheffield and released it by a river on the Isle of Wight.

In the 1990s Mrs Norris of Surrey introduced seeds to ‘spare land’, gave them away to a passersby, a work colleague and an Irish market gardener friend, scattered seeds in local woods and took them on holiday to France and Spain (!)

I believe that these stories reveal a worrying attitude to the environment, which may be one of the roots of our present biodiversity problems, and can be summed up thus: “My local environment is of no account, and contains nothing of interest, and I can introduce anything I like into it with no significant consequences.” The remorseless spread of I. glandulifera, and its deleterious effects on local environments all over the UK, demonstrates just how wrong this attitude is!

During his Bhyundar Valley expedition in 1937 F.S. Smythe had the following experience:

“For a little distance we followed a rough shepherd’s track but presently lost it and had to force our way through a wilderness of pink-flowered balsam (Impatiens Roylei) growing fully eight feet tall. Had it not been for the labour we might have appreciated the beauty of these flowers which covered acres of the valley floor in a sheet of bloom; as it was, we were heartily glad to regain the path, dripping with sweat after the unusual exercise.”

It so happens that I know exactly what he meant! A couple of years ago I was making my way from one part of Urmston Meadows to another; this involved negotiating a narrow track – much of which was ankle-deep in mud. To my left was a Himalayan Balsam ‘thicket’ - which was easily eight feet tall.

After a while I encountered a path which entered the balsam thicket, and I assumed that it marked an entrance to a detour around the mud. I followed the path – and after a while realised that it was going downhill and was not a detour. Eventually, I came to the river bank and concluded that the path had probably been made by fishermen. I turned around and then realised that the boots that I was wearing had little traction on the slippery, muddy, upward slope that I was trying to negotiate. I fell over a couple times and generally floundered around in the midst of this tall, impenetrable balsam thicket. After a while I began to imagine the headline: “Body of Chorlton man found on river bank at Urmston.” 

Somehow, though, I survived, and eventually emerged wiser, sweatier and a lot muddier.

Dave Bishop, July 2012

References:

Beerling, David J. and Perrins, J.M., ‘Impatiens glandulifera ROYCE (Impatiens Roylei Walp.)’, Journal of Ecology, 81, 367 – 382, 1993.

Grindon, Leo H., ‘The Manchester Flora’, William White, 1859.

Robinson, William, ‘The English Flower Garden’, Hamlyn ed. 1984 (first pub. 1883)

Rotherham, Ian D., ‘Himalayan Balsam – the human touch’, paper presented to the Institute of Ecology and Environmental Management Conference, Birmingham, 2000

Smythe, F.S., ‘The Valley of Flowers’ Cadogan Books ed. 1985 (first pub. 1938)

Stace, Clive, ‘New Flora of the British Isles’, Cambridge University Press, 3^rd ed., 2010