Purple Shamrock (Oxalis triangularis)

Dear Readers, my dear friend S gave me this plant last week, and ever since I’ve been completely fascinated. We often think of plants as being static beings, but of course they aren’t, they grow and move towards the sun and do lots of other things, but usually over a timescale that’s slower than ours. Purple Shamrock, however, opens its leaves like butterfly wings at the first sign of light, before collapsing like an umbrella once it’s dark. Have a look at a film showing the phenomenon here. This kind of movement is known as photonasty (not to be confused with video nasty), and it refers to ‘nastic movement’ – this is normally found in plants and relates to them being able to change the pressure of water within their tissues. With the Purple Shamrock, the leaves are pumped full of fluid in response to light, enabling them to maximise the surface area exposed to the sun. When it’s night time, the turgor pressure falls, and the leaves collapse. Amazing!

Purple Shamrock is not a ‘the’ shamrock associated with Ireland and St Patrick’s Day in particular. Instead, it’s a wood sorrel – we’ve covered several species of the family before, from the lovely Wood Sorrel that can be found in ancient woodland to the little brown and yellow Procumbent Yellow Sorrel which pops up at the bottom of urban walls, and Pink Sorrel, a pretty garden plant that is increasingly hopping over the wall and heading off into the wild.

No chance of Purple Shamrock doing that any time soon in the UK, as the plant isn’t frost tolerant: it comes originally from South America, in particular Brazil, Paraguay, Bolivia and Argentina. It has established itself in the wild in Florida and Louisiana, where presumably the temperature and humidity matches its requirements. In Brazil, the plant is thought to bring good luck (the trifoliate leaves are thought to represent  the Holy Trinity), and is often given as a New Year’s present.

Much to my astonishment, I’ve found several articles which suggest that this plant is edible, along with one which points out that it is ‘potentially poisonous’ to humans and pets. Discretion is definitely the better part of valour with this one. It contains oxalic acid, which can aggravate the kidneys, and can bind calcium, making it unavailable to the body. All in all, it’s much better to look at than to munch upon.

Apparently my Purple Shamrock should enjoy indirect light, not too much water, and will undergo a dormant period (so I’ll need to be prepared). At the moment it’s popping out flowers and leaves like nobody’s business. What a delight it is! I actually have a room in my house where I try to save ailing house plants, but it’s so nice to have one that seems happy. Let’s see how it gets on. Maybe I’ll be dividing it up and giving it to friends myself soon. Propagated plants are such a joy to share.

And of course, here’s a poem. I read this twice, and it grew on me. See you what you think.

Away
By Vona Groarke

We have our own smallholding:
persimmon tree, crawl space, stoop,
red earth basement, ceiling fans, a job.

Hours I’m not sure where I am,
flitting through every amber
between Gales and Drumcliffe Road.

I paint woodwork the exact azure
of a wave’s flipside
out the back of Spiddal pier

and any given morning pins
a swatch of sunlight
to my purple shamrock plant.

My faithless heart ratchets
in time to slower vowels,
higher daylight hours.

I grow quiet. Yesterday
I answered in a class of Irish
at the checkout of Walgreen’s.

I walk through the day-to-day
as if ferrying a pint glass
filled to the brim with water

that spills into my own accent:
pewtered, dim, far-reaching,
lost for words.