Celebrating the Wild Side of Yorkshire’s Coast & Country: How the Poor Man’s Orchid has swept across our landscape and into our ecology
The Poor Man’s Orchid
I first saw Himalayan balsam and Japanese knotweed as I walked to school in the 1960s and 1970s, on the otherwise barren River Sheaf at Heeley in Sheffield. Now, once again with the torrid summer heat, the air is heavy with the pungent fragrance of exotic balsam. A lady once wrote to tell me of how on the River Aire near Leeds, she was overcome by the balsam smell and swooned in a faint. I have written numerous papers and articles on invasive plants and animals, and several of these are free to download from the UKECONET website. In particular, the ones on the history of plant invaders and on Himalayan balsam in particular, you might find interesting and hopefully amusing too. How people have, actively and deliberately, spread Himalayan balsam across Britain and around Europe was fascinating to discover. Balsam has no halfway house, people are either lovers or haters.
Increasingly, rivers, hedgerows and even some woods are dominated by a rich array of exotic and sometimes invasive species. We have the stunningly beautiful Himalayan balsam spread along the River Sheaf and the River Derwent in the 1940s by Nobel Prize-winning scientist Sir Hans Krebs. It is side-by-side with the pernicious and problematic Japanese knotweed, and the poisonous and almost vicious giant hogweed, now being reported from across the region. Faced with these apparent threats, our island wildlife seems under siege and there are campaigns to control or eradicate invasive aliens from ‘natural’ habitats. In some cases, these are fully justified; Japanese knotweed for example, causes millions of pounds damage to development sites alone, recent causalities being the new Wembley Arena, and the London Olympics village.
However, in many cases the situation is by no means clear-cut. The reactions to exotic species raise huge social and ethical issues as well as an array of economic and environmental ones. My friend the late Dr Oliver Gilbert was a pioneer of interest in both distinctive urban wildlife and in exotic species. His view was that change is inevitable, and we should learn to accept and even love exotic plants like sycamore and Himalayan balsam in our woods. This is hugely controversial, and many people shudder at the thought of the Oak-Bluebell woods becoming Sycamore-Balsam woods. However, with climate change and the impacts of urbanisation some change of this sort may be inevitable. Ollie was also the champion of Japanese knotweed along the urban rivers. His pioneering research undertaken in Sheffield during the 1980s led to his suggestion that these were distinctive and appropriate urban communities to celebrate and foster. Excitingly he found an ‘ancient woodland flora’ (bluebell, wood anemone, and greater woodrush) establishing under the dense stands of knotweed all the way along the urban rivers Sheaf and Don.
Today many local conservation groups are concerned by the insidious, creeping threat, which some exotic species pose. Therefore, as invasive, alien species are on the up, some of our local wildlife groups are taking action. In Sheffield’s Ecclesall Woods for example, the site where our long-term quest to understand the spread of Himalayan balsam began, the local Friends of Ecclesall Woods have it under control; a testimony to perseverance and sheer effort. However, the rivers provide arteries for colonisation and this stunningly exotic annual flower, Himalayan balsam, has spent the last hundred years or so, gradually displacing native wild flowers. This plant has attractive, stunning even, pink flowers and irresistible exploding seedpods which many people love, but as Himalayan balsam is spreading out of control and native flowers are suffering. Introduced to gardens from the Himalayas in the early 1800s, each year it grows rapidly up to 3 metres high. A giant annual flower, it spreads speedily with its seeds floating downstream to new sites and deliberately dispersed by people. This has occurred for instance, along the Moss Brook, a Site of Special Scientific Interest river that flows west to east just south of Sheffield. So here on the southern edge of Sheffield, in the Moss Valley between Coal Aston and Eckington, a battle is taking place. The area is well known for its woods, countryside walks and wildlife, just a few miles from Sheffield city centre. In recent years, volunteers from the local Moss Valley Wildlife Group have been trying, with some success, to control the spread of this invasive plant. However, the alien species is still spreading fast to threaten the status of the Site of Special Scientific Interest, home to rare and protected native plants. A few years back, to help in the battle, the Wildlife Group was awarded a £9,000 National Lottery “Awards for All” grant to provide professional support to tackle the balsam. At that time, the then Moss Valley Wildlife Group Secretary Celia Jackson said: “We are delighted and can now make a real difference to combat this continuing problem in our Valley. Invasive Himalayan Balsam threatens special sites and native flowers.” Nevertheless, the problem continues but the funding does not, and an aging population of many conservation groups compounds the problems.
On the urban River Don, a group called SPRITE (The Sheffield Partnership for Rivers in the Town Environment) has established to bring together anglers and conservation-minded individuals who wish to improve and care for the urban watercourses. A regional ‘Invasive Species Network’ set up by the South Yorkshire Biodiversity Research Group, the regional ECONET, to aid the dissemination of information and recording of species distributions, has supported this work. SPRITE has a big advantage of a core group of ‘youngish’ and enthusiastic individuals prepared to dedicate a lot of time to working with the community and tackling the problems. Another approach, elsewhere in the country such as the south-west, has been to call in the aid of groups of fit, active young people, such as in one case the Marines! Knotweed and balsam are particular problems in the warm and wet south-western regions of Britain, and both Swansea City Council and Cornwall County Council have had marked success in control by the appointment of dedicated specialist to coordinate and implement rigorous control measures. In Swansea at least, this was in part because they realised that the immense cost of site remediation for knotweed infestation was stopping companies investing in, and moving to the region.
Finally, there is a downside to all this effort, to which I refer in an earlier article about ecological fusion and ecosystem hybridisation. Control is not just for today, but forever; not a message that everyone wants to hear. However, there is evidence that in time some invasive plants do ‘settle down’ and become a part of a new recombinant or hybrid ecological system. Canadian pondweed, a once notorious waterways and wetlands invader, now barely merits a mention. In part, this seems to be because even more serious and competitive plants have overtaken it, but also, it has genuinely lost its vigour. Over time, plants acquire diseases, pests and predators, that affect native species but which at first, are not adapted to the invaders. In New Zealand for example, our British gorse is highly invasive and aggressive, and in the absence of a pre-adapted, set of New Zealand insect herbivores, grows to gigantic proportions with bushes 20 to 25 feet high. Only time will tell, but maybe in urban ecological communities, the invaders will in time become part of new and relatively stable systems. That is what Oliver Gilbert might have predicted. These new ecologies will be constantly gaining new members from garden escapes and other sources and expanding out into the countryside may well cause angst for those trying to conserve native nature. Pressure such as sprawling urban development, atmospheric pollution and climate change mean that stability of today’s ecological systems is not a long-term option, and change of sorts is inevitable. We have to learn to live with the changes and to manage our ecologies to better provide and conserve or protect the things we desire and value; and that will take a huge amount of dedication and effort.