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Seeing the day that’s in it, I’m reminded of a passage in Robert Lloyd Praeger’s wonderful autobiography-cum-travelogue ‘The Way that I Went‘ where he ponders the correct botanical identification of the legendary Shamrock of Saint Patrick.


Statue of Saint Patrick on the Hill of Tara

One of the major issues with the identification of the true Shamrock is that the story of Saint Patrick using it to illustrate the nature of the divine Trinity is a very late attestation. It is not mentioned in Patrick’s writings, nor in any of the early biographies such as the Book of Armagh or the Tripartite Life. In fact, the story first appears as recently as 1727 in Caleb Threlkelds ‘Synopsis Stirpium Hiberniacum‘ a.k.a ‘A Treatise on Native Plants‘.

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The First mention of the Shamrock-Saint Patrick legend by Caleb Threlkeld in 1727. It also shows that ‘Excess in Liquor’ on March 17th is nothing new.

In his search for the true Shamrock, Praeger leans heavily on the work of his friend, the naturalist Nathaniel Colgan, who published his first collection of self-termed ‘Shamrockiana’ in 1896.

In ‘The Shamrock in Literature: a Critical Chronology‘ (JRSAI, vol. 6, pg. 211), Colgan scours the Irish sources for the earliest references to the Shamrock (or Seamróg as Gaelige) and finds a cluster of attestations from the latter half of the sixteenth century from Campion’s ‘Historie of Ireland‘ (‘Shamrotes, Water Cresses and other herbs…’) through to Gerard’s famous ‘Herbal‘ (‘The common Meadow Trefoils, which are termed in Irish, Shamrockes’) where the eating of Shamrocks by the native Irish in times of want is stated to be a widely observed custom.

Seamróg is etymologised as Seamair óg or ‘little clover’ which would suggest it is either identical with, or closely related to, one of the species of Trifolium common in Irish meadows. Seamair however, is the generic Irish term for all clovers and the fact that Shamrocks are mostly collected in early March before any flowers appear means that discrimination by non-specialists of the various native trefoils is not necessarily reliable.

The majority of the historical sources plump for the Shamrock to be Trifolium repens or the White Clover, with a couple suggesting the alternative Red Clover, Trifolium pratense.

trifolium repens

White Clover

trifolium pratense

Red Clover

However, a curve-ball was played in 1830 by the British botanist James Ebenezer Benecho who proposed in a paper ‘On the plant intended by the shamrock of Ireland‘ (JRI, 1831-32) that the true Shamrock was in fact the Wood Sorrel, Oxalis acetosella. This identification was also raised again in a scurrilous fashion by the Manchester Guardian during the last century.

The identification of the true Shamrock with Wood Sorrel is based on the fact that many of the early sources describe the Shamrock being used as a foodstuff by the native Irish. Clovers, both the white and purple varieties, are bitter and unpalatable, whereas Wood Sorrel has a pleasant, sharp, almost lemony taste and is still eaten today by wild food enthusiasts. There has been continuous, if unproven, speculation since Benecho’s paper that the White Clover, in particular, is an introduced species and so cannot be contemporaneous with Saint Patrick. Benecho suggests that Wood Sorrel was much more prevalent in medieval times before the widespread deforestation and clearance of its natural habitats led to its substitution by the Clovers as the Shamrock of popular memory.

wood sorrel

Wood Sorrel

Colgan made a survey of the Shamrocks worn in his day (early 1890’s) to see which plants the modern Irish were identifying as the national emblem (The Shamrock : an attempt to fix its species, Irish Naturalist, v.1, pg. 95-97 & v.2, pg. 207-211). Surprisingly, the result was  roughly 50/50 between the White Clover, Trifolium Repens, and the Lesser Trefoil, Trifolium minus/Trifolium dubium. The other contenders: Purple Clover, Trifolium pratense and the Black Medick, Medicago lupulina, were very much disfavoured and the the Wood Sorrel, Oxalis acetosella, is missing entirely. The survey was repeated in 1988 by the botanist E. Charles Nelson for his definitive 1991 Book, ‘Shamrock: Botany and History of an Irish Myth‘ with virtually identical results.

Trifolium_dubium final

Lesser Trefoil in flower

So what does Praeger conclude?  He favours the identification of the Shamrock with a ‘clover of small neat leaves – a condition always fulfilled by the Lesser Trefoil, but requiring starved specimens of the White Clover’. Certainly, the Lesser Trefoil is the variety you will most commonly see being sold commercially in Ireland on Saint Patrick’s Day and it is the variety used for the traditional Saint Patrick’s day presentations at the White House.



Shamrock: Botany and History of an Irish Myth, E. Charles Nelson, Boethius Press, Kilkenny, 1991


Bess Lovejoy, Smithsonian.com, No one Really Knows What a Shamrock is