This is one of those occasions when I am actually going to sing the praises of someone. The moment I started to write this entry a particular Latin phrase jumped into my head Res Ipso Loquitor, Its modern use is a rather obscure legal use but its meaning is extremely apt for this matter. It means "The thing speaks for itself," and it does!. The podcast is a clear explanation by an internationally renowned expert of ragwort hysteria, the subject of this blog. I already knew about this man's expertise and his eloquence in explaining things is unsurprising but it was an extra bonus to hear him speaking. He speaks with the resonant dulcet tones you would expect from an actor who is employed as a narrator on a television documentary. Please do go and spend the time to listen to the podcast which I will link to
I am going to quote and add some comments to a small section of a transcript of the podcast. It is one of a series of podcasts from the Knepp Wildland and features the expert Professor Mick Crawley of Imperial College London being interviewed by the project's co-owner and author of the brilliant book Wildling, Isabella Tree.
It begins with an introduction
Isabella Tree:
Hello, and welcome to the Knepp Wildland podcast with me, Isabella Tree — author, conservationist, it and co-owner of the Knepp Rewilding Project.
This month we’re discussing a plant that is probably the most controversial native wildflower in the British Isles. It’s been a spectacular summer for common ragwort. You may have seen it erupting in fields near you, on roadside verges, in urban parks — anywhere there’s a scrap of space for it.
People either love it, or they absolutely hate it and want it erased from the face of the planet.
So to get to the bottom of these intense ragwort passions, and to try and nail down some facts, I’m standing in acres and acres of ragwort in the middle of Knepp, with our old friend Mick Crawley, Emeritus Professor of Plant Ecology at Imperial College London — who probably knows more about ragwort than anyone else on the planet. So lovely to see you, Mick.
After introducing the plant we get on to this piece.
Isabella Tree:
So before we get into why people hate it, let’s describe the benefits. Why do we love ragwort here at Knepp?
Mick Crawley:
There are two ways insects benefit from ragwort. One is by eating it — there are two very important species that do, and about 20 others that depend on it but don’t affect its growth much.
The other, more widespread benefit is from its nectar and pollen. Dozens of species — bees, flies, butterflies, moths, beetles — rely on it, especially because of its timing.
Isabella Tree:
Yes, I’ve read it flowers when little else is available.
Mick Crawley:
Exactly. It’s late-flowering, and can last into October or November. For nectar-feeding insects at this time of year, it’s a lifeline.
Isabella Tree:
And that incredible acid-yellow colour of its flowers is visible even to night-flying moths — some of our best pollinators.
So we have this wonderful, hugely beneficial native wildflower. And yet, every year at Knepp, when ragwort comes into bloom, we brace ourselves for the hate mail — people accusing us of being irresponsible, even of deliberately trying to kill animals. What’s going on here?
Mick Crawley:
I don’t think any plant has more fake news about it than ragwort.
And that fake news is exactly what I blog about here and despite it being debunked , we find the Facebook posting of this podcast has been full of people who either didn't bother to listen to the podcast at the top of the post OR just didn't understand it, repeating the fake news and even refusing to believe people who are telling them they are wrong with good evidence.
It continues:-
Isabella Tree:
I wonder if part of the myth comes from the Injurious Weeds Act. Ragwort was listed along with creeping and spear thistles and docks as an injurious weed to be controlled for farming. That lodged in people’s minds — that it’s a poisonous plant that shouldn’t exist anywhere.
Now just for clarification that law is actually called the Weeds Act and "injurious" in this case actually means, exactly what was defined in the Agriculture Act 1920 and that was something that was harmful to the interests' of arable agriculture back then. It doesn't mean causes injury and the other plants are on lists of wild foods that can be eaten harmlessly by people who go foraging.
Then we get this correct interpretation of this law, as regular readers will know
Mick Crawley:
That’s right — but it’s not illegal to have ragwort.
Isabella Tree:
Exactly. But people insist landowners are legally obliged to remove it everywhere.
Mick Crawley:
Which is completely untrue. In fact, government guidance says it shouldn’t be removed from nature — it’s far too beneficial.
Another important section is this
Mick Crawley:
Cutting off flowers before seed sets reduces the death rate, because the plant keeps its root reserves and grows again next year — turning a biennial into a perennial.
Pulling the plant up leaves broken root fragments in the soil, each producing a new rosette. So instead of killing one plant, you multiply it by four or five.
The only sure way to kill ragwort is to let it flower and set seed. Once it invests all its root reserves into reproduction, it dies. Counterintuitive, but true.
Isabella Tree:
That is counterintuitive. And yet people blame us for ragwort spreading into their gardens miles away — which isn’t how it works.
Mick Crawley:
Right. Experiments show that adding extra ragwort seed to grassland makes no difference — recruitment isn’t seed-limited. It’s disturbance-limited. Seeds falling on intact grassland mostly die in the shade. For new plants to establish, you need disturbance: pig rooting, rabbit scrapes, cattle hoof prints. That’s why ragwort thrives here at Knepp.
At Silwood Park in Berkshire, where I work, we haven’t had ragwort for six years — because rabbit haemorrhagic disease wiped out the rabbits, and without their disturbance, ragwort can’t establish.
Isabella Tree:
So when people see ragwort, it’s not “blown in” from elsewhere — it’s come from the seed bank under their feet, triggered by some disturbance.
Mick Crawley:
Exactly.
Just to expand on this recruitment thing. This is about individuals being recruited into a population rather like the army recruits people into their population of soldiers. so to clarify this with a more detailed explanation. Scientists have tried adding extra ragwort seeds to grassland, but it makes no difference this is because there are already plenty of seeds around. There are plenty of seeds of this plant all over the place but that most of them can’t get started. When seeds land on thick and unbroken grass, they usually die in the shade. For new ragwort plants to grow, the ground has to be disturbed a bit like when pigs root around, rabbits dig, or cattle leave hoofprints. These bare patches let the seeds see the light and take root. That’s why ragwort does so well at Knepp, where animals are free to roam and stir up the soil.
Oh and before I finish while the podcast diplomatically says it is mystery where the fake news comes from . Regular readers here will know precisely where it comes from. In my honest opinion most of it comes from the officers and the staff of the British Horse Society!
As you can see this podcast is all really excellent stuff and there are many other good points in the complete podcast. So I urge you all, please, please go and listen to it. It really is excellent so go to the website of the Knepp project and listen to the complete thing. It is well worth your time. Episode 39: The Plant People Love to Hate - Knepp
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