Rhododendron removal – Winter Hill 24th March 2024
Easter – the time when we celebrate the invention of chocolate and the four day bank holiday. It’s also the time for the annual BCV Easter Egg Hunt and the traditional ‘losing’ of at least one egg on the task site as an offering to the Easter bunny. But before we get to that bit we had some work to do.
There was a whole lot of hopping going on on Winter Hill, BCV and members of the British Mountaineering Council were back removing rhododendron. For more info on why we hate rhodys read an earlier post through this link.
It was a long hard walk up the hill, carrying mattocks, spades and loppers to boot, but it was a good view once we got to the top, or it would have been if not for the rhododendron scattered everywhere. But that’s why we were there.
As the task was classified as HARD we had no expectations that the day was going to be pleasant jaunt in the hills, no this was one of the the most demanding tasks we’ve done for a while. One volunteer quit the field with a back injury, and one took an hour to make the journey to the work site. The survivors managed to take down a good number of the magenta menace, but still plenty left.
As it’s Easter we had our traditional Easter Egg Hunt, not quite the way we usually do though. Because of the treacherous terrain and lack of anywhere to hide eggs we did a lazy egg hunt. The lazy egg hunt was basically putting the eggs in a pile and making the best of it. Many thanks to Jane for supplying the eggs.
There are an estimated 15,000 invasive species in the UK, 49 of those species are considered to be harmful to wildlife, and one of those species makes up one of out bread and butter tasks – Rhododendron ponticum. People ask ‘Why do you kill those plants, they’re nice, they have pretty flowers?’ Pretty flowers.. hmm… let’s see
The name Rhododendron translates as “Rose Tree”, ponticum refers to the plant’s home territory around the Black Sea (Latin name Ponticum Sinum). It is a member of the Ericaceae family, the same family as heather and bilberry, which explains why it likes acid soils.
Rhododendron was first introduced to Britain in 1763 from Gibraltar and was soon firmly installed in throughout the country in the ornamental gardens of stately homes. The fashion for this insidious threat continued up to the mid 1890s with R. ponticum becoming the favoured rootstock for grafting and cultivation. But a series of harsh Victoria winters wiped out many evergreen species, including some of the less hardy rhododendron. The remainders soon reverted back to their wild state, and as many country manors fell into disuse and management of stately grounds declined, the rhodys spread. Armed with an array of phytochemical weaponry and unimpeded by our native wildlife, Rhododendron ponticum soon began to dominate the countryside. BCV have seen the effects of this first hand at sites such as the Anderton Centre and Ravenden Clough, both sites were once the grounds of country estates, both sites were overrun with rhodys once left to their own devices.
2007 first Anderton resi.
What makes our enemy so deadly? To start with its roots, stems, leaves, flowers, pollen and nectar are loaded with grayanotoxins, a cocktail of phenols and diterpenes that have a range of toxic properties including anti-viral and anti-fungal properties. How R. ponticum employs these chemicals is still open to debate. One theory is that the grayanotoxins kill the mycorrhizal fungi the grows on the roots of any competing plants, preventing those plants absorbing essential nutrients such as phosphorus. Another theory is that the toxins kill soil fauna such as worms and microbes which consequently inhibits nutrient cycling and availability of nutrients to other species. The theories surrounding methods of dispersal for grayanotoxins are equally as diverse. Researchers argue that toxins enter the soil via roots; by leachate from decaying leaf litter; by runoff from the plants leaves and stems and also by air. There are other theories that claim the toxic soil effects of rhodys are overstated and the likely cause of their dominance is that they shade out other species and out-compete them for nutrients and pollinating insects.
The toxicity of rhodys is beyond question. In addition to their damaging effects on habitats no native insect can survive nibbling rhody leaves, sheep and horses can die from eating them, and even humans have been harmed. There are records, dating back to 400 BC, of honey made from rhododendron nectar adversely affecting people who eat it. Apparently it has both hallucinogenic and laxative effects on the sufferer, so it’s not something you want to spread on your toast in the morning. Surprisingly the bees are immune to rhody toxins.
What other survival strategies to rhodys use? Well, they can spread both vegetatively, such as rooting at points where branches touch the ground, and also by seed. It takes a rhody between 12 and 20 years to mature and produce flowers, each of those flowers can generate as many as 3000 seeds each, that means a good sized shrub can produce around 7,000,000 seeds per year. The seeds are distributed by wind and can travel up to 500 metres from the parent. Winter Hill near Belmont shows just how effective this method of propagation can be, with rhody seedlings scattered across the hillside many hundreds of metres from the nearest mature individuals.
And the bad news doesn’t stop there. Rhododendron also spread a deadly fungus, Phytothora ramorum or Sudden Oak Death. First identified in California the fungus appeared in the UK in 2003 and is arguably now the greatest threat to our woodlands and heathlands. Rhododendron is responsible for the extinction of 150 native British species in the last 100 years. As more habitat is destroyed by the encroachment of rhododendron the more species suffer- trees, mosses, ferns, insects, amphibians, mammals, birds, nothing is unaffected. Pretty flowers? No.
This task we joined up with the British Mountaineering Council on Winter Hill to do battle with our arch-enemy. We were last up here around 8 or 10 years ago but BMC have been keeping up the fight on their own for the last few yeas. It’s a big job as rhodys have spread extensively across the hillside, and unfortunately the fires that ravaged Winter Hill in 2018 missed this area otherwise our work would have been done.
There are aliens amongst us. There are 36 species of concern in the UK, invasive plants and animals that have been introduced to our countryside that have no natural controls and spread without mercy. Himalayan balsam (Impatiens glandulifera) is an invasive species, and it is this species BCV spend hundreds of volunteer hours each summer trying to control.
The many names of balsam: Indian Balsam, Nuns, Jumping Jacks, Bobby Tops, Copper Tops, Gnome’s Hat Stand, Jewelweed, Ornamental Jewelweed, Policeman’s Helmet, Kiss-me-on-the-Mountain
Balsam flower
Balsam was introduced to the UK in 1839 from the the foothills of the Himalayas, mainly northern India, Pakistan and Nepal, by Victorian botanists and collectors of exotic plants. But their pretty pink flowers would soon be seen outside of private collections as they began their colonisation of riverbanks and wetlands. Without the natural biological controls found in their native habitats balsam soon spread, and in the last 50 years especially it has become a menace to conservationists across the country.
Himalayan balsam can dominate habitats, its canopy blocks out light, restricting the growth of native flora. Pollinators are attracted to balsam blossom in preference to other flowers, this reduces the species diversity of plants and the vertebrates and invertebrates that would use them by affecting local ecosystems and food webs. It alters soil conditions, as being shallow rooted once the balsam dies back there’s less soil binding, increasing the risk of erosion and the siltation of watercourses. It blocks access to paths and waterways, costing time and money to clear it from affected areas.
Being an enemy of the people it has some heavy legal controls to make it think about its behaviour, here’s a few things taken from various government and local government websites.
Because of negative impacts on the UK environment and economy, Himalayan balsam is listed as a species of special concern under retained European Union (EU) law. This means it is an offence to plant or cause these plants to grow in the wild, or intentionally release them into the environment. Schedule 4 of the Invasive Alien Species (Enforcement and Permitting) Order 2019 removes plants listed under the EU IAS Regulation from Schedule 9 of The Wildlife and Countryside Act 1981, although the same offence applies. Also, Himalayan balsam plant material (including soil contaminated with seeds) is a ‘controlled waste’ under the Environmental Protection Act 1990 which means it can only be transported by a registered waste carrier to suitably permitted or exempt sites. Transfer notes shall be kept for each load for a minimum of 2 years.
Breaking the rules can result in a fine, a 3 month prison sentence, or a good telling off and your promise to tidy up not to do it again. But balsam has a good lawyer so there are exemptions:
Landowners do not have to remove listed plants growing wild from their land. However, they must not intentionally grow, cultivate or allow to reproduce wild listed plants. If a listed species is already growing on your land, including parks, estates open to the public or private gardens, or in ponds, lakes, waterways on your land, either private or open to the public, the species is not considered to be intentionally kept or cultivated. So you’re not committing an offence because you’re not intentionally keeping or cultivating it.
If you want to grow balsam or any invasive species as part of a collection or for commercial purposes you will need a permit.
Balsam for Bashers
bashing balsam
So, what can you do to stop the spread? Can you bash it? Yes you can. Every summer between May and early August conservationists across the UK take part in the activity known as balsam bashing. This is preferably done before the seed pods appear and always with the landowners permission if on private land.
Balsam can be controlled in a number of ways: it can be sprayed with herbicide, which isn’t the preferred option of environmentalists; it can be introduced to grazing animals, but there’s only so much they can eat. There is also ongoing research into the use of fungal rusts that can take down vast areas of balsam but that’s outside of the average bashers means. So, the methods most commonly used are cutting and pulling.
Balsam can be cut with a mechanical strimmer or brush cutter, or with hand operated weed whackers. This method is great for clearing large areas of balsam but does leave an unsightly mess of cut balsam on the ground. Also, to be most effective the cut needs to made between the root and the first node, the first bulge on the stem above the root. Balsam can re-shoot if the stem is cut too high so accurate bashing is essential.
Roots and node
Hand pulling takes longer and works well on smaller areas. Just hold the stem and gently pull the roots out of the ground, then you can either snap the roof off, again below the first node, or crush it mercilessly in a neat pile. Not severing the root and just throwing it back on the ground undamaged can result in the balsam re-rooting and it can continue growing albeit in a bit of a twisted shape.
If the balsam has seed pods then any kind of bashing will release the seeds and give you more work for next year. Seed pods have an explosive method of distribution. As the two halves of the pod mature there’s an increase in tension, at this point even a gentle touch with a finger tip can cause them to twist open, firing seeds for several metres in every direction. Putting a bag over the seed head before pulling will catch the seeds, but is a bit time consuming, so it’s best to do all your bashing long before this stage. What you do with the seeds you catch in the bag is a problem as they would be classed as hazardous waste, keeping them on site is probably the best option. Bashing the same area over five years or so will eventually exhaust the seed bank leaving it balsam free. BCV have had success with this at several locations.
Balsam for Boiling
Some people argue that balsam benefits bees and pollinators, which is true, but there is a cost to other native species as noted previously. However, there is one benefit balsam has that other invasives generally don’t- it is edible. As long as the balsam hasn’t been sprayed with herbicide it can be eaten: its seeds can be used in curries, the leaves can be used in salad, soups and stews, the flowers can be used in gin, smoothies, jelly, ice cream, jam, crackers, and champagne. An extract of balsam is even used as a homeopathic treatment for anxiety. The leaves taste a bit bitter and the flowers don’t taste of very much, the stems are best left alone, but whatever floats your boat, however caution is needed so see the box below. Also, collecting the balsam does raise the problem of transporting invasive plant material to another site, a bit more thought might be needed on that score.
Himalayan Balsam is very rich in minerals, so shouldn’t really be eaten in large quantities. It also contains calcium oxalate, which can be harmful, cooking thoroughly should break this down. People with arthritis, kidney or bladder stones, gout, hyperacidity and rheumatism should avoid eating balsam completely.
So there you go, brief guide to balsam and how to bash it, the rest is up to you.
Bash Street Kids
Sources: Gov.uk – Invasive non-native (alien) plant species rules in England and Wales Jones D (2022) Public information on invasive species in Wales: Himalayan balsam. Welsh Government. foragingcoursecompany.co.uk Royal Horticultural Society
Balsam bashing. Words that send dread and fear through the souls of conservationists everywhere. The yearly exercise of ripping up Himalayan balsam, the persistent invasive that never goes away, can be soul destroying. But should be pack up our weed whackers and let the balsam win? No. Balsam may be here but it doesn’t mean it is here to stay.
Over the last few years we have been bashing the balsam at Firwood Fold and we are now seeing the results of all that work. Compared to last year the area covered by balsam has significantly reduced, so much so that we had to think of something else to do in the afternoon. So, what is the story of balsam. The plant with the pretty pink flowers was introduced to the UK in 1839 by the Victorians as a decorative garden plant. And like many of the Victorian’s favourite exotic plans soon went on the rampage across the countryside’s water ways. Balsam creates dense stands that out compete native species, in winter it dies off leaving riverbanks and the shores of water bodies exposed to erosion. It also interferes with fish spawning areas. There are some plant experts who dispute the negative aspects of balsam and think we should just live with it. Generally though, besides the Victorians. the only creatures that likes it are bees.
Last year we did this exercise in August when many of the plants were in flower, this year we got here a bit earlier and with the exception of a handful of pink blooms the balsam was in bare naked. So, we gave it a good thrashing and left no stalk unbashed. Hopefully next year there will be even less or none at all.
With Firwood being the home ground of Bolton Green Umbrella’s organisers Barb and Trevor Hackett it seems appropriate to mention that Green Umbrella has been awarded a Bolton at Home Stars of the Community award, this link for more info.
We wanted a mission, so they gave us one. Clear the jungle trails of the insidious invader, rhododendron. The Victorians brought rhody across as a bit of exotic colour, their strange love of alien species would be their undoing. Soon it had set up a beachhead and was storming across the our green and pleasant land like a magenta menace. It had to be stopped.
Our platoon set out on its dawn patrol, but Dawn had nothing to do with it so we apologised and carried on to Ravenden Clough. We were horrified at what we found, rhodys to the right of us, rhodys to the left of us, the way ahead was buried under rhody. Captain Francis cried “For Harry.. and maybe William”, and our dirty three-quarter dozen went on the attack.
We forced rhody back a metre at a time, uncovering the paths of glory, but the heat, the smell, the sweat, the ground soaked in sap, it was a nightmare; the horror, the horror. We had to dig a trench to drain away the spoils of war, it all felt like our longest day, but finally it was all quiet on the rhody front. We cleared down to the crossing over the brook and stopped, we didn’t want to go a bridge too far.
The day was ours and it was time for the great escape to the pub lead by the our beer hunter. It all happened, we know because, we were there.
