Invasive non-native species in and around Walton le Dale primarily include problematic riverside plants like Himalayan balsam and giant hogweed, alongside aquatic and woodland threats managed locally.
- Himalayan Balsam: Chokes native riverbanks along the River Darwen and River Ribble.
- Giant Hogweed: Found near local river confluences; poses a serious public health hazard due to toxic sap that causes skin burns.
Currently, these problems aren’t being dealt with particularly well locally.
It was interesting to note that a well-know YouTuber visited the area to specifically look at the Himalayan Balsam and Giant Hogweed. He recently release tow separate videos that talk about each of these plants and how they are effecting our local environment. The channel is ‘Leave Curious’, on which are published hopeful restoration stories, and more.
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Britain’s Most Dangerous Plant Is Spreading
There’s a seriously dangerous non-native plant that is thriving in Britain.
Unknowingly, hundreds of people each year are burnt by its sap. The damage from this plant isn’t immediate as it requires sunlight to trigger a chemical reaction before giving thirdderee burns.
I’m going to tell you how you can identify it so you can avoid it. I’m also going to talk about where it came from. We’re going to look at how serious this in invasion is and you know whether if we can get rid of it.
Holy smokes. There it is. You see that tall plant standing behind me over there? No joke. When people try and deal with this plant, they wear literal hazmat suits. I need to tread very carefully today. Oh boy, there’s loads of it over there. There’s loads of it through here. My head is telling me to go back to the car and put on some longer trousers.
I never wear trousers during the summer, but today I’m about to go through here to this toxic scary plant, I think it’s I think it’s the least I can do. So, I’ve come to a section of the river Darwin in the north of England, just outside of Preston. And to say that the non-native plants are taken over here, well, that’s an understatement. Let’s go in and let’s not touch absolutely anything. Can’t even see where my feet are going.
What’s this growing here? Holy smokes. Damn, that’s big. That’s going to be 4 metres tall. Actually, great shout putting on these trousers. These thistles are no joke. Oh there it is. I’m standing on it.
I have to be seriously careful right now.
So, the plant which we’re looking at here is giant hogweed. This time of year in the height of summer, it has reached its absolute peak. It’s a monster. These ones here are 3 metres and there’s some much larger ones further back in there, but I’m not going to go in there. You know, they can easily reach 5 m tall. So, besides from their obvious height, I’m going to show you the ways which you can identify this very dangerous plant. The stem of giant hogweed is actually hollow inside. It just looks quite rigid, but you can also distinguish it by these kind of like purpley blotches which are all up the stem. And the leaves, well, they’re pretty big, too. They’re kind of jagged and sharply divided, and they can stretch up to 3 metres across. These ones here, they’re a little bit smaller. And at the very top, it holds an enormous umbrella-like cluster of small white flowers. You can see that there’s some flowering here, although I think some have already passed.
Giant hogweed can actually be confused for several native species. In particular, you’ve got common hogweed, cow parsley, wild angelica, and hemlock. Now all of these species will produce these umbrellas of white flowers. Just remember with giant hogweed is it is going to be a damned sight taller you know 3 metres plus maybe but also remember those large jagged leaves and the purple blotches on the stems. I’ll absolutely say to you if you’re not sure don’t go up don’t interact with it.
Do not touch it. I feel like this is something to really communicate with children. You know, my kids would absolutely walk up to something like this, think it’s awesome, snap it off, and next thing you know, you’re in a world of trouble.
So, what actually does make giant hogweed so dangerous if you just brush past it or, god forbid, snap it off. So, inside the leaves, the stems, the roots, and flowers of giant hogweed is a thick, clear sap. And this sap contains an organic chemical compound called fura and cohumarins. I think I’m pronouncing that right. I’ll put the word on screen for you now. But here’s the real sinister bit. On their own in the dark, these chemicals won’t hurt you. But the moment they interact with UV light, even on a cloudy day like this, they undergo a violent phytochemical reaction. The toxins will bind directly to your skin’s DNA, completely destroying your cell’s ability to protect themselves from UV radiation. Within 24 to 48 hours, redness and inflammation sets in. And it wasn’t it won’t stop there. These will turn into seriously painful blisters. And these won’t just be surface blisters. These will be comparable to thirdderee burns. And the nightmare, it doesn’t stop there. Even after the blisters heal, the sap alters your skin’s pigmentation, leaving dark purplish scars that can last for years. And this causes extreme sensitivity to sunlight. And you know, even in the future, if you if you spend time in the sun, these areas can just flare up and blister again. And you absolutely do not want to get this in your eyes as it can cause temporary or even permanent blindness.
I’ve never been so cautious making a video. Like you guys know me, I’m normally like barging, smashing through stinging nettles and undergrowth. But joking aside, when people deal with this, when they’re trying to eradicate it, they’re wearing full-on hazmat suits. But we’ll talk about whether if that’s even possible in just a minute.
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Where did it come from?
Well, like many of the dangerous and wacky non-natives which we have in this country, we of course have the Victorians to thank for bringing across giant hogweed. Its true home is actually thousands of miles away in the damp, rich soils of the Caucus Mountains, stretching between the Black Sea and the Caspian Sea. In the 19th century, British botanical explorers were traversing the globe, looking for the biggest, rarest, and most exotic plants to bring back home. In 1817, seeds of the giant hogweed arrived at Kew Gardens. To the Victorians, this plant was a masterpiece. It was impressive the way it stood tall, its flowers, its leaves. They often planted it in their gardens, in their estates, often next to their lakes, ponds, and rivers. Where they planted it was actually a big part of the problem of how it escaped. But one thing which they absolutely underestimated was its reproductive powers. And by 1828, this plant had already escaped.
Giant hogweed absolutely loves disturbed lands. And with the river networks moving the seas around, it began its it began its onslaught across the nation. So, if we know it’s dangerous and we know where it is, why don’t we just dig it up and get rid of it? As it turns out, eradicating giant hogweed is one of the most frustrating and complex environmental challenges which we have here in the UK.
A single giant hogweed plant can produce up to 50,000 seeds and those seeds can lie dormant in the soil for several years. So, if you marched up here and you were wearing full protection, hazmat suit, mask, and everything, you had a machete and you chopped it down, it would largely do nothing. The tap root of hogweed goes deep down into the ground and it’ll grow back within a few weeks. While it is a huge problem, you can begin to get a hold of it locally.
It takes a focused multi-year strategy, which includes applying targeted herbicides to leaves or physically cutting tap roots deep below the soil surface before the plant can drop its seeds. And if you miss a single plant or you stop managing an area for even a year, it’ll just come back with an absolute vengeance. It really is a slow war of attrition which has been played out across miles of UK waterways. The river’s only over there. I would imagine this was carried over this way.
Ultimately, the story of giant hogweed for me is much more than just about understanding a a toxic and dangerous plant. While the overriding message which I want you to take away from this video is just please be careful. Tell your family, tell your children, you know, in inform schools about this kind of thing.
But I do feel that there is another valuable takeaway here in the world of rewilding in the world of nature restoration. There is a massive debate going on at the minute. People are getting incredibly anxious about the idea of reintroducing lost native predators like lynx or the wolf. There are groups of people which still worry so much about these creatures coming back. We worry about the danger, the risk to our safety, and whether if we can handle sharing our landscape with something which has teeth. But look at this plant. It is a highly toxic, hyperaggressive invader that inflicts severe, agonizing third degree burns on hundreds of people every single summer. Statistically, you are infinitely more likely to be hospitalized by giant hogweed on a Saturday stroll than you ever would be by a wild lynx or wolf. And if we can live alongside these three or five metre biological weapons which aren’t really meant to be here, maybe we can learn to live alongside some species, some creatures which are meant to be here.
That’s just my takeaway. What do you think about that idea? What do you think about this plant? What relationship have you had with this plant? Let me know down in the comments.
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This Explosive Plant Is Invading Britain
There is a plant growing across Britain right now that literally fires its own seeds through the air like miniature missiles. And it might look completely harmless with its sweet perfume and delicate pink blossoms. But this plant carries a secret weapon, an explosive mechanism that forcefully shoots its seeds through the landscape to colonize entire river systems. It smothers native wildlife, replacing rich, diverse river banks with a single impenetrable species and leaves the ground beneath it literally crumbling into the water. It’s pretty bad right here. Look at it. It is just rife with invasives here.
Over there is where we film the hogweed. You can see the giant hogweed over there. It’s this tall stuff. But today we’ve come back for something else. And the plant in question is Himalayan balsam, So it forms in these dense thickets here and it’s disappearing down to the river. It kind of smothers everything out. Oh, but not the hogweed. You can see the hogweed is getting away there. There’s a huge patch of it back that way which we’ll take a look at in a minute. I’m just just going to see what’s up here. Look at these giant hogweeds. Stay away from them, please.
So, we’re just outside of Preston (in Walton le Dale). This is the River Darwen, which then feeds into the River Ribble. And, yeah, it’s pretty bad here. So, just looking at this plant, you could be forgiven for thinking that this is one of Britain’s most beautiful flowers. And they are, very pretty. Bees love them, too. So, how do you identify them?
Well, the stems, they’re hollow and they’re a reddish pink, almost looking like a giant juicy stalk of celery. These ones here are quite young. Look, there’s a fairly large one down there. Look. See? And the leaves, well, they are long spear shaped with
fine sawlike teeth along the edges, but the dead giveaway are the flowers. They’re delicate helmet shaped blossoms that range from a pale pink to a deep purplish magenta. And they look a little bit like wild orchids.
Now, while it does look gorgeous and the the flowers, they do smell rather sweet, do not underestimate what this plant is really doing to Britain’s ecology. So, what makes a harmless looking pink flower such a threat? Well, Himalayan balsam grows in dense, impenetrable monocultures. In early spring, its seeds germinate weeks ahead of our native flora. It shoots up at a terrifying speed, forming a thick canopy that blocks out nearly all sunlight. Native plants like nettles, ferns, and wild garlic don’t stand a chance, and they are literally smothered and starved of light before they can even establish.
Now, if you’re standing here on a summer’s afternoon like today, you could be fooled into thinking that this is good for wildlife. You’ve got bees buzzing around it, other pollinators going into the flowers and taking the nectar. But the truth, the truth is very different. So, while bees clearly benefit from this rich nectar, ecologists worry that such an overwhelming food source pulls pollinators away from native flowers like fox gloves and willow herb, leaving them unpollinated. And worse still,
while generalist bees actually visit and pollinate these flowers, um, they don’t really fulfill that niche for a lot of our specialist insects and pollinators here. Think of these Himalayan balsam patches as like a high sugar junk food zone that ultimately starves out the wider ecosystem.
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These monocultures turn what could be a diverse native ecosystem into what is an ecological desert that’s wrapped up in these pretty pink flowers. But here’s the here’s the really tricky bit about this plant. Wonder if I can get one of these to go. Oh, there you go. These are the exploding seed pods. Now, might be a little bit early in the year, but some of these are starting to turn into these green almost ribbed seed pods. And as these pods dry out, tension builds inside its walls like a tightly
wound spring. The tiniest touch from a passing animal or a heavy raindrop or a hiker’s boot causes the pod to split apart, curling backwards in a millisecond and firing the seed several meters through the air.
Oh, that one exploded in my eye. And it’s this seed dispersal mechanism, which means that a single plant can conquer meters of ground. But when you couple that with having waterways which are carrying the seeds around, it’s no wonder that it’s getting out of control. And here’s the other catch with it. While it forms these kind of dense areas in the winter, it completely dies off and then you’re just left with, you know, complete bare ground. And a lot of that bare earth can then just be washed into the rivers and that will smother all of the fine gravels which a lot of fish species and invertebrates rely upon. And here’s an example of that bare earth which results from just the domination of the balsam. And you just get this like really loose soil.
So how did Himalayan balsam get here? Well yet again like many of our most invasive non-natives it was the Victorians. Its native home is thousands of miles away in the damp valleys of the western Himalayas, stretching across India and Pakistan. In 1839, plant hunters brought seeds back to the UK.
Victorians were instantly captivated by its vibrant orchidlike flowers, rapid growth, and of course, the fun quirk of his exploding seed pots. It was sold as a cheap, high impact ornamental plant for grand country gardens. Because it was so easy to grow, gardeners swap seeds and land owners planted it along estate streams to look pretty. And it wasn’t long before it made its way off out beyond these gardens and into our river systems with these exploding sea pods, you know, next to rivers. They would just be carried downstream.
So, looking at the scale of this plant, can we realistically beat it? Can we eradicate it? And I think the answer to that is, you know, it’s not going to happen overnight, but we can absolutely start to turn the tide on this thing. But we must be real about how aggressively this plant spreads. Reports show that it increases by 645 square kilometers each year. That’s an area nearly half the size of Greater London. It’s currently conquering damp river banks and woodlands across the UK. And while this does sound like an unstoppable ecological disaster, I do believe that we really can get a handle on it. And that’s for a few reasons.
Unlike other non-native invasives, Himalayan balsam is actually pretty straightforward to deal with. It’s not that much of a problem. They have laughably shallow root systems. I mean, look at that. Just comes out almost too easy. And unlike giant hogweed, you can actually walk up to to this one and pull them straight out without any worry that you’re going to get a burnt. And unlike other non-natives, the seeds, they don’t lie dormant in the soil for decades. I actually think it’s just a a few short years. So if you have a coordinated approach between groups across catchments, you can really begin to turn the tide on this. And the other thing is that it’s, you know, it’s volunteer friendly communities.
Volunteer groups go out and they do what’s called balsam bashing, which is where you want to get in before the seed pods change. I think we’re a little bit late now because a lot of them are bursting, but you want to get in before the seeds develop into this explosive state. And uh yeah, you just want to bash it down and pull it out. One thing I’ve learned from making these videos is that awareness alone isn’t enough. If we’re going to restore nature, people need a genuine way to become part of the solution.
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