Wednesday Weed – Sun Spurge

Every Wednesday, I hope to find a new ‘weed’ to investigate. My only criterion will be that I will not have deliberately planted the subject of our inquiry. Who knows what we will find…..

Sun Spurge (Euphorbia helioscopia)

Sun Spurge (Euphorbia helioscopia)

It was a very short walk to find the Wednesday Weed this week – I noticed this plant one hundred metres from my front door. It’s called Sun Spurge, and I recognised it from when I was a little girl, and used to break the stems so that I could squeeze out the latex-like sap. What a little horror I was! The sap can cause dermatitis, or even temporary blindness if you get it in your eye, but there was something about the thick white liquid that made me respectful of it, even as a child. Children seem to have a better instinct for what is safe and what is dangerous in the natural world than we sometimes give them credit for.

Sunspurge and Feverfew 001Euphorbias are an interesting family, with many cultivated species – their flowers are often green, and so they have an alien, exotic appearance. Sun Spurge is an annual plant of poor, disturbed soil, and once I’d noticed this one, I saw little versions of the plant all the way along the road, but only on the south side – it seems to have a strong preference for hot, dry conditions, hence its common name.

Back to the sap. Many people swear that it will cure warts, but it has been used for other, more private reasons. In Plants Britannica, Richard Mabey mentions that Manx fisherman applied the sap as an aphrodisiac, and that its name in Wiltshire was ‘Saturday Night’s Pepper’. My mind is fairly boggled at how this property of the plant was discovered, and the extent to which this playing around with  toxic substances must have led to disaster. There must have been some unfortunate accidents, as Mabey mentions that sour milk could be used as a cure in the event of overuse.

All I can say is, don’t try this at home.




9 thoughts on “Wednesday Weed – Sun Spurge

  1. Lynn D. in Oregon

    I pride myself on being a pretty observant person, but I always learn something from you. I love cultivated Euphorbias and have several in my garden, but I never noticed that this “weed” which dominates my vegetable garden is related. I rarely allow it to get to the flowering stage, but now I will let a few specimens bloom. I wonder if it’s the cause of the brief dermatitis I often get after weeding.
    Do you have purslane in England?

    1. Bug Woman

      Hi Lynne, Sun Spurge is notorious for irritating the skin, so maybe it is the cause of your dermatitis – I do find that as I’ve gotten older I’ve become more sensitive to certain plants as well – stinging nettle barely used to give me pause, but these days I’m a mass of welts and hives. Not a pretty sight at all!

      And yes, we do have purslane…this is probably the commonest one:

      1. Lynn D. in Oregon

        Hah! Americans and British have to be careful when discussing plants. What you call marigolds, we call calendula. Purslane in the U.S. refers to this plant:

        It grows rampant in my garden along with the sun spurge (scourge?). It is supposed to be a nutritional powerhouse so I’ll put it in a stir fry tonight

  2. Bug Woman

    Ah yes, two nations divided by a common language…! Let me know how the stir-fry goes. At least that’s not something you’d want to do with Sun Spurge…

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  4. Bug Woman

    There are very few wild ones in the UK – about 15 species – but lots of ‘domesticated’ ones that escape from peoples’ gardens. I was quite surprised to find out that Annual Mercury, my current ‘Wednesday Weed’ is a euphorbia – the Sun Spurge looks much more typical.

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