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Talkback: Ragwort

Didn't realise what this weed was until I saw this blog. I have one plant of it in one of my borders and have been impressed by how attracti...

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Didn't realise what this weed was until I saw this blog. I have one plant of it in one of my borders and have been impressed by how attractive the flowers are. The leaves don't look good at all, but apart from that it is adding a great splash of colour.

It's the main food plant for the cinnabar moth caterpillars so it's not all bad. 

There is the most astonishing hysteria about ragwort. It is by no means "extraordinarily toxic" to animals. The digstive systems of cattle and horses convert pyrrolizidine alkaloids PAs found in the plant to toxins that damage the animal's liver, but neither cattle nor horses will eat the living plant unless starving because it is extremely bitter. Sheep will eat ragwort without coming to harm and in years gone by farmers would put an old ewe or two in with cattle to control ragwort. It is a real problem if it gets into hay or other feed as the plant loses its bitterness when dried. It is illegal to sell haay containing ragwort. It takes more than "A relatively small amount of the stuff" to harm horses or cattle and the vast majority of ragwort poisonings involve illegal hay or animals being starved.

There are many causes of liver problems in horses and poisoning is just one of them. PAs are just one possible cause of poisoning. PAs are present in many native species. Unfortunately an urban myth has taken hold and many websites publish what they describe as signs of ragwort poisoning, which are in reality the signs of liver failure (however caused).

The toxic effects of ragwort are extraordinary in that all parts of the plant are toxic, even when dead, also the toxic effect is cumulative such that when an animal shows symptoms treatment is not often successful.

A toxic dose can be can be eaten in one go or little by little over an extended period of time. Ragwort in preserved forage is certainly very dangerous as Bill has mentioned but if ragwort is in grazing it will be come more palatable as it seeds, wilts and dies back.  

Sheep do come to harm if they eat ragwort especially if they are young. Older sheep can tolerate more but are not resistant as such. Ragwort affects a grazing animals, cattle and horses are particularly sensitive to ragwort poisoning and also chickens and pigs. 

Ragwort poisoning is not easy to diagnose even at post mortem and yes liver damage can be due to many causes, but toxic it is and in my opinion keeping it out of grazing land and preserved forage is essential part of good livestock husbandry.

Bill regards this as hysteria, I regard his stance as dismissive of the problem. The fact that he and others aim to repeal the weeds act and ragwort control act may explain his position. These acts only require removal of ragwort where they are likely to spread to grazing land and land used to produce preserved forage so there are still plenty of other areas where ragwort can (and does) flourish.

Anyone who has any concerns about ragwort and animals in their care should speak to their vet


Roy Hill
All I can say is that the field next to my garden which houses a horse of no great immaturity (and occassional grazing cattle and sheep) has had ragwort growing. Last year especially.

I've now got a bit of an over-run area which has ragworts and willowherbs. This year I have a breeding population of cinnabar moth (ragwort obviously) and elephant hawk moth (willowherbs).

Gardens can be used to grow animals as well as plants.

With regards to insects it should be mentioned that insects 'see' at different wavelengths to the human eye, well into ultraviolet ranges. Flowers/plants can have markings which are hidden from human eyesight.



It isn't hysteria!  

Ragwort is highly toxic to grazing animals and particularly to horses.  Well that's not really true.... the only reason why it's not such a serious issue for cattle and sheep is that they're ordinarily slaughtered and eaten before they suffer the serious consequential efffects of ragwort poisoning.

As it's covered by the Ragwort Control Act and it's also toxic to people and via skin absorption so frankly, it's dumb growing it and handling it

We've provided respite care for horses that have been serious neglect cases and including had ragwort poisoning and believe me it's not pretty!   They were ultimately euthanased to prevent further suffering and after having developed photosensitisation and liver failure.

If you know of a field that contains ragwort and with grazing horses then the owner is in breach of The Animal Welfare Act as well as the Ragwort Control Act.  They could be liable to prosecution for causing suffering and rightly so!






I have Ragwort in my garden for the Cinnabar moths like nut said  Its their main host plant.


Have you got many this year Fishy? I haven't. 


Now you come to mention it nut,no I haven't. I counted three caterpillars today,OK they were well grown but I usually have way more than that.


I've seen 3 or 4 moths and 5 caterpillars. A poor showing

 A few years ago every ragwort plant would be covered.


Last year was much better.I think maybe you get these variations in numbers through most species. Cuckoos are down a massive 60% I think they said on springwatch this year,or have declined by that in recent years,I can't remember which. I can't recall the last time I heard one but my brother said they are still common in Scotland.


You're right about the ups and downs. Thrushes are down here, skylarks very much up


My wife constantly has me pulling the stuff out of our grazing field when she spots it.. it's also pretty hard to kill by the way, most home use weed killer like glyphosate doesn't touch it. 

Fairly easy to control though, it's more of a problem if it gets hold in an field it can be a nightmare to get rid of.





We only have it occasionally and it's a constant battle with some idiots letting it grow rife.   Our highways dept being the worse culprits!  We pull it up including roots and burn it.




I was aware Ragwort was toxic to animals but didn't know it was the only food plant of the cinnabar moth. Photo captures of its caterpillars feeding on it and an ID search after brought me to this moth. The photo below is not the best due to wind movement this day but for anyone else reading this forum post it might be interesting to see.

My sighting of ragwort above was in sand dunes at a beach a short distance along from St Andrews in Scotland. In all my visits to this coastal strip I had never noticed the many feeding caterpillars on this plant. In fact I had never really taken a second look at the Ragwort.

Two weeks later we returned on another visit (this time armed with a video camera to capture the many feeding caterpillars for my blog) to find the same area of Ragwort striped of leaves and flowers with only main stems left! These caterpillars could be one of nature's way of controlling this plant pest - although in reality no match for the growth a spread of this plant.

Small tortoiseshells caught my eye this time and following one with my camera I found it feeding on a new patch of Ragwort and there I found the cinnabar moth caterpillars once again - even more of them!

I captured a great piece of video footage of the small tortoiseshell appearing to deliberately knock of one of the caterpillars off the Ragwort and feed where it was (must get it uploaded one night). I also spotted Ringlet butterflies feeding on ragort on this coastal location too. It's great what you discover when out with a camera  



That's lovely to see


Nutcutlet, I was fascinated and captivated but the numbers of these caterpillars. I really can't believe I have never noticed them before over the years we have visited this area.


We discussed in the past, maybe not on this thread, the cycles of these and other wild creatures. I'd never seen them before we moved here 22 years ago. Then for a few years there were lots. Now very few again.


The caterpillars ingest the toxins from the ragwort and have some way of using those very same toxins for their own defence.That's why they are yellowy orange/black stripes. Any animal that is red,orange or yellow combined with black in nature spells danger to a predator.


Nutcutlet, my visits here are more recent and not too frequent so it would be easy for me to miss previous discussions. This one caught my attention tonight and as I had a photo thought I'd share it.. 

Hopefully your moth numbers will increase again in future years

Fishy 65, I was reading that when I looked up for info on this caterpillar. Nature is fascinating isn't it