The Real Irish Shamrock

The true Irish Shamrock, as identified by Nathaniel Colgan c. 1893 is a clover. It is not one of any or many clovers, it is one species, collected from a majority of counties at that time and with the exception of a very few plants, the majority were Trifolium repens or a form of this plant – White clover also known as Dutch Clover.


A few years ago, when I was in the United States, I made enquiries of the old lady whose house I was staying in as to the name of a plant she had, and I was told in no uncertain terms that it was a Shamrock – and she wondered how I could claim to be Irish if I didn’t know what it was!! The plant I saw was in no way anything like what we call Shamrock and even here, I notice differences in what is being sold as Shamrock from one place to another – so, the day I found this particular paper in the Irish Naturalist, I was delighted. I have found photographs and taxonomic descriptions of three of these four plants. The fourth plant mentioned Trifolium minus, “a species listed here that should ‘share the honour equally’ with Trifolium repens” – has been re-classified, and is now considered to be a form of Trifolium repensMany say that there is no true shamrock, it is simply a species of clover and can be any one of a number of different species- there are web sites that do say that Trifolium repens is the Irish Shamrock, but rarely is the person who came to this conclusion mentioned. Those sites that do name Nathaniel Colgan as the botanist, tend to give the impression that there are still other plants that fall into a general category of ‘Shamrock’Nathaniel Colgan collected plants from many Irish counties (not all), he did receive specimens from the Gaeltacht areas – those places that he considered that the people would produce the plant that was most likely the original ‘shamrock’ and because “the Irish-speaking districts of our island, where old national usages may be assumed to have the greatest tenacity of existence………..” and so, the conclusions drawn by Nathaniel Colgan on the basis of his work, given the time period this was carried out in should really be taken as evidence that there is one true shamrock. Trifolium repens and that Trifolium minus, considered at one time to be a separate species is really a form of Trifolium repens, that is to say the same plant, with some very minor differences, that do not accord it the distinction of a different species.

A ‘taxonomic’ description for those who may not be familiar with the word is a description of the parts or bits of a plant or animal that help us to distinguish between it and another similar plant or animal. These differences may be minute and hard to recognise unless you are familiar with the structure of any plant or animal.

The Shamrock : A Further attempt to fix its species

by Nathaniel Colgan

published in the Irish Naturalist 1893

On the approach of last Saint Patrick’s Day I was induced, chiefly by the kind offer of assistance made me by the editors of this Journal, to take in hands once more the inquiry into the species of our national badge, begun some years earlier, with the results detailed in the issue for last August. A notice to subscribers was accordingly inserted in the March number of this year, so framed as to ensure that all specimens sent in response should be certified as genuine by competent authorities, while, at the same time, as a provision against a not improbable lack of interest in the subject amongst the subscribers to the Irish Naturalist, some three dozens of circulars were prepared and sent by post to selected points in the Irish-speaking districts, chiefly along our western sea-board. These circulars, in almost all instances, were addressed to Roman Catholic parish clergymen; and, as I had fully expected, the percentage of replies they brought me was very much larger than in the case of the printed notice. Of the circulars, twenty per cent were answered, a proportion not far short of expectation. As for the printed notice distributed through the agency of the Irish Naturalist, I cannot presume to say exactly how small the percentage of answers may have been. Out of the whole body of subscribers, however, only eight forwarded specimens of Shamrocks; but, of these, one sent no less than five, another, four, and a third, three specimens, each certified as genuine by a distinct authority.

List of names of those who sent plants

In addition to the plants thus secured, Mr. F. W. Burbidge, Director of Trinity College Botanic Garden, supplied me with a root, certified by one of his gardeners, a Tipperary man, as the real Shamrock, and part of the stock grown in the Gardens, and supplied as such to English inquirers; another specimen was bought from an advertiser in the Co. Louth, who offered the plant for sale, at a not unprofitable price, “as the true Irish variety,” and, finally, three specimens were bought in Dublin on the 17th March as real Shamrock, from three different itinerant vendors, each of whom was required to exercise the most scrupulous care in the selection of the genuine plant from the obviously miscellaneous collection in her basket. (These three plants matured into three distinct species, Medicago lupulina, Trifolium repens and Trifolium minus)

Altogether, thirty-five Shamrocks -were secured and carefully planted and labelled, after they had been provisionally classified according to species. A study of the minuter distinctions of Trifolium repens, Trifolium minus and Medicago lupulina, made it possible to carry out the classification with confidence even in the undeveloped stage in which most of the specimens reached me: In no single instance, indeed, in which the plant survived up to the flowering and fruiting season, (and only two out of the total of thirty-five succumbed to the extraordinary dryness of the remarkable spring and early summer of this year), was this provisional classification found in error; so that my Patrick’s Day determination of these two as T. repens and T. minus, respectively, may be accepted as accurate. Of the surviving thirty-three plants, all had flowered and many had fruited by the 23rd June, T. minus in all cases keeping well ahead of T. repens. By the end of June the entire crop of Shamrocks, or, at least, specimens of the thirty-three plants of which it was made up, was harvested and garnered, that is to say, dried, mounted, and labelled, for the satisfaction of obstinate adherents of Trifolium repens.

The results of this harvest may be most clearly shown thus :-
19 Shamrocks matured into Trifolium repens.
12 Shamrocks matured into Trifolium minus.
2 Shamrocks matured into Trifolium pratense.
2 Shamrocks matured into Medicago lepulina.

It will be seen that the results of this year’s inquiry shows, contrary to my expectation, a decided preponderance in favour of T. repens. But if we add in the results of the former inquiry , the balance between the two species is almost redressed.