Sadly, my garden isn’t quite this big.

My Dad was visiting again the other day, making an absolutely lovely job of our garden as usual (our garden is beautiful, despite the fact that my last bit of flora-based input was sowing some grass seed six years ago), and we took a trip to the National Herb Centre.  This is a wonderful place for a day trip if you’re in North Oxfordshire. Never mind the cafe, playground and interesting plants, it’s worth the trip just for the truly spectacular views.

We had lunch and wandered around the many, many rows of medical plants, dye plants and, of course, herbs.  I had no idea there were that that many types of mint.  I plumped for the chocolate one.  Seriously, it’s a plant that smells of chocolate mint.  How brilliant is that?  I’m hoping for fruits in the form of After Eights.  You never know.

But it was on the way out that things got really interesting.  Dad spotted something and called me over to look at some fairly unprepossessing plants with little round, yellow flowers.  A card described them as ‘electric daisies’ and explained that the flowers, when eaten, produce a sensation of an electric shock, or popping candy, and are used as a treatment for toothache and mouth ulcers.

Acmella oleracea, the “electric daisy”

Displaying my usual sort of ‘I wonder what will happen if I just mix this with that’ recklessness, I took a tentative nibble from one side of a flower.  At first, it tasted of nothing so much as, well, pretty much how you might expect the middle bit of a daisy to taste: sort of grassy and mushy.

Then the weirdness began.  A mild prickling sensation quickly developed into full-on tingling, but not big pins-and-needles tingling.  It was a more subtle, evenly spread, effect.  The best way I can describe it is like someone pouring lemon juice all over your tongue, having somehow first extracted the flavour of lemons.  The peculiar, but not unpleasant, sensation persisted for a good ten minutes, and was followed by a strange rush of saliva.  It was most odd.

The spilanthol molecule.

It turns out that these little yellow flowers (technically, inflorescences) are chock full of interesting chemicals, most interestingly spilanthol which acts on the nerves in the mouth and causes saliva production.  It’s also been shown to be antibacterial and anti-inflammatory, so this plant’s traditional use as a cure for toothache is based on a bit more than some in the ‘it might help and it can’t do any harm, can it’ school of plant remedies.

Interestingly, continuing my ongoing obsession of such things, it’s a chemical that actually does permeate skin, causing a local anaesthetic effect.  And it can also, temporarily, stop muscles in your face from contracting – a bit like botox, but conveniently with less of the deadly toxin-ness.  In fact, someone’s even registered a patent for a cosmetic treatment using spilanthol.

But why on earth has a plant evolved something that eases toothache and gets rid of wrinkles in humans?  Perhaps not surprisingly, from the plant’s point of view, these effects are simply happy accidents.  Spilanthol is a form of biological pest control – in other words it kills off critters that might be silly enough to try and make a snack of electric daisies.  It’s particularly good at killing off yellow fever mosquitoes (mosquitoes eat plants when they’re not annoying you), which is good for both the plant and for humans since these little pests spread such delights as yellow fever and dengue fever.

Acmella oleracea flowers may not exactly give you an electric shock, but they can act as a painkiller, insect repellent and anti-ageing cure.  Having learned a bit more about these little wonders I’m starting to think they might just be the most useful plant ever.  Isn’t nature amazing?

You can buy electric daisies, and their seeds, at the National Herb Centre.  I’m quite tempted to go back for another one actually…