THE POISON GARDEN website       

Friday 10th August 2012

Last week, I said that, as people seem more likely to believe anecdotes rather than evidence, the answer to people believing myths and misinformation might be to offer anecdotes based on the evidence rather than the evidence itself.

I thought I’d try this with Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort, partly because I wanted to share some pictures I’m shamelessly proud of.

There’s a small, fenced piece of land close to our local swimming pool. Because it is unused and entirely left to itself, it has produced a magnificent showing of common ragwort.

As it was a, rare for this year, warm, fairly sunny day, the flowers were providing plenty of food to a variety of pollinating insects.

I’m not an insect novice, let alone expert, so I wouldn’t dream of trying to put names to these, but I’d be pleased to hear from you if you can identify them.

I did get one of the smaller creatures onto my hand if that helps with identification.

Because, for me anyway, it is hard to get good quality stills of such active creatures I took some video.

Now that the ‘ah, pretty’ stuff is out of the way, the anecdote can begin. I want to point up three things about ragwort.

This small piece of land is one side of a track and on the other side is a field with horses in it. Just so no-one can accuse me of trying to hide things, here’s a picture of those horses plus a ragwort plant against the fence.

There were a few more, but only a few. For the rest of the story, we need to go back to the first picture, or rather a close-up of the piece of land.

The other plant you can see to the right of the ragwort is Rumex obtusifolius, broad-leaved dock. This picture of most of the horse’s field shows just how much dock it has in it.

And how little ragwort.

So, the first point my anecdote proves is that common ragwort does not spread easily from one piece of ground to another.

Rumex obtusifolius is one of weeds listed in the Weeds Act 1959. It is toxic if ingested because it has a high concentration of oxalates that harvest essential calcium from the body. A high dose can be very damaging to the body’s functioning and can result in extremely painful kidney stones. Death is a possibility, though unusual.

The second point is that people get very upset about Jacobaea vulgaris and quote (and frequently misquote) what the Weeds Act 1959 requires landowners to do about it. But, they never seem to mention Rumex obtusifolius though it should be dealt with in exactly the same way.

But the most telling point is that you can see a very few ragwort plants and lots of dock. In other words, these plants haven’t been eaten by the horses living in this field.

The science says that common ragwort does not spread easily, that it is essential for a whole range of insects and that horses ignore the living plant because the taste is so unpleasant. This one field proves that the science is right.

What the science can’t explain is why people are so fanatical about common ragwort but don’t care about broad-leaved dock.

'Is That Cat Dead? - and other questions about poison plants' is now also available in Kindle form from Amazon.