Diarmuid Breatnach
This month the shamrock is blooming all around. The cluster flower is not very prominent individually but together can produce a yellow-green carpet effect, yellow for the flowers and green for the leaves.
(Photo: D.Breatnach)
Who is to say that the shamrock has a yellow flower? Why not the white clover? Well, amateur botanist and zoologist Nathaniel Colgan (1851-1919) once asked people from around Ireland to send him specimens of what they believed to be an Irish shamrock and identified the five most common plant species, of which the two most common were the yellow (flowering) clover followed by the white. A hundred years later, Dr Charles Nelson repeated the experiment in 1988 and found that yellow clover was still the most commonly chosen. According to Wikipedia, yellow clover is also the species cultivated for sale in Ireland on Saint Patrick’s Day and is the one nominated by the Department of Agriculture as the “official” shamrock of Ireland.
But sometimes, the yellow-flowered species Trifolium dubium (Irish: Seamair bhuí) can be found growing next to the white-flowered Trifolium repens (White Clover; Irish: Seamair bhán), although they never really intermingle.
(Photo: D.Breatnach)
The clover family belong to a group of plants that have the ability to fix nitrogen in nodes around their roots and, as a result, provide nutrition for plants that need nitrogen. The plant, like the rest of its family, produces pods but in the shamrock’s case, the pods are tiny and contain only a single seed. Pods protect the development of seeds until they are ready to shed (or in some cases, like the gorse or furze, to explode!).
In cropped or mown lawns, or in poor soil, the shamrock hugs the ground. However, given conditions for growth but having to compete with other plants for sunlight, it will grow long stems reaching upwards.
Once flowering is over, probably in August, one can dig up a small section and transplant to flower box or pot in order to harvest sprigs of it for St. Patrick’s day on March 17th (a tradition that is nothing as old as people might think).
(Photo: D.Breatnach)
But nobody planted the shamrock in the lawn – it got there by its own natural methods, possibly by wind or in animal excreta. Unlike the lawn on which it has set up its colonies, which was seeded on raked earth or, more likely, laid in grass turf rolls, it is in fact a part of wildlife in the city.
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rebelbreeze 
We have the shamrock flowering in our garden – in the county of Angus, Scotland!
What a coincidence youse Angus lads posting this. We picked some in Glen Clova and it is thriving but nae flooers, on my wee balcony down here in Fintry, Dundee. My mum brought back some from Ireland years ago and it flowered white. There was a machine in Derry that would dispense a pack o’ seeds for a euro or pound coin but they never lasted. Have only ever seen white flowering shamrock in the Angus Glens. Have to get me timings right for next spring then!
Thanks, Michael — not sure why you refer to this Irish-based blog as “Angus lads”.
As the article says, it is the yellow-flowered that is the “shamrock” recognised by most Irish people. The plant you’ll be searching for is Trifolium dubium according to scientific name — it has many other names in localities — and you should be able to find places where it grows through botanical societies etc near you. It is definitely widespread throughout Europe. https://en.wikipedia.org/wiki/Trifolium_dubium
Dia Duit Diarmuid. I was responding to a post above where the folks had referred to themselves having shamrock growing and blooming in their garden in the county of Angus, Scotland. ‘Lads’ is a local Scots term addressed to a body of people and has gentle echoes of them being bothy lads as applied to hired farm labourers. My Montrose born and raised mother in law would aye ask us if ‘youse lads’ wanted our tea! I would hope that a weel read lad like yourself has read Lewis Grassic Gibbon’s ‘Sunset Song’ novel about farming life in the North East from here. Interestingly where Gladstone had an estate and where we think David Cameron is holed up the now. And further, me shamrock is blooming purple flooers. Now I am wondering whether yon lovely Scots song, which ends ‘Sunset Song’, ‘Flooers o’ the Forest’ could refer to the shamrock? Great line in that song which mourns Culloden: ‘The English by guile, hae wan the day’. A vital lesson! The BBC made a TV version of ‘Sunset Song’ and it is excellent. Make time to watch it! https://www.bing.com/videos/search?q=you+tube+sunset+song+tv+series&view=detail&mid=EE3700896DB4A2BE82D6EE3700896DB4A2BE82D6&FORM=VIRE
Sé do bheatha, we use “lads” a lot too and even women among women are known to do it. I will put that novel on my reading list, go raibh maith agat. Unfortunately while replying here, I am unable to see previous comments.
Sorry, but purple-flowered plants cannot be shamrock but are instead another relative, another clover. As the article pointed out, the Irish opinion was only ever divided between white and yellow-flowered but came down pretty conclusively on the yellow-flowered.
I think clover is more of a meadow or glade plant than a forest one, unlike say bluebells, wood-sorrel (which has clover-like leaves but is of a different family), foxglove, bramble rose etc.
Yes, beware their guile — all the while!