The shamrock and Saint Patrick.
Although the shamrock is closely associated with Saint Patrick, it is more likely that the shamrock was worn it as a symbol of the cross - the old Tua Cross, presumably and not the modern one - rather than of the Trinity. Shamrock itself is simply immature trefoil, or young clover, and the name is an anglicisation of seamair óg or "young clover". The myths themselves, though, are much more interesting. The shamrock, it is said, symbolises the Trinity, that is, the Christian idea that there is one God but three Persons in the one God, the Father, the Son and the Holy Spirit. Before the Christian era it was a sacred plant of the druids of Ireland because it's leaves formed a triad. Famous stories tell of how St. Patrick used the shamrock in his teachings. Preaching in the open air about God and the Trinity, he illustrated the meaning of the Three in One by plucking a shamrock from the grass growing at his feet and showing it to his congregation. Just as the shamrock is one leaf with three parts, so God is one entity with three Persons. The legend of the shamrock is also associated with the banishment of the serpents from Ireland by a tradition that snakes are never seen on shamrock and that it is a remedy against the bites of snakes and scorpions. Because the shamrock was a sacred plant to the druids, and three was a mythical number in Drudic religious practice, Patrick was probably well aware of the significance of the shamrock as a teaching tool.
On the subject of green plants, it should be said that the colour of St. Patrick was not actually green, but blue. In the 19th century, however, green came to be used as a symbol of Ireland. Thanks to plentiful rain and mists, the "Emerald Isle" is indeed green all the year 'round, which is probably the inspiration for the national colour. Although many people would presume that the shamrock is also the national emblem of Ireland, this is not so. The national symbol of Ireland is the harp.
Three is Ireland's magic number. Numbers played an important part in Celtic symbolism Three was the most sacred and magical number. It multiplies to nine, which is sacred to St. Brigid. Three may have signified totality: past, present and future, sky, earth and underground. Everything good in Ireland comes in threes - the rhythm of Irish storytelling is based on three-fold repetition. This achieves both intensification and exaggeration. " Three accomplishments well regarded in Ireland - a clever verse, music on the harp, the art of shaving faces."
On St. Patrick's day, a member of the British Royal Family presents Shamrock to the Irish Guards regiment of the British Army, so integral is the shamrock in the history of the Irish people.
The shamrock is a fragile little plant, and doesn't keep long out of its habitat. A fresh sprig in the morning will have dried and withered by noon, and can look a bit limp. Recently a few bright sparks have invented a little lapel sachet in which the shamrock is both grown and worn, and will bloom until the last of Patrick's pot is drunk. The Irish have a few difficulties translating ingenuity into gold over a last few thousand years, but being Green wasn't one of them.
HISTORY OF THE SHAMROCK
In written English, the first reference to the shamrock dates from 1571, and in written Irish as seamrog, from 1707. As a badge to be worn on the label on the Saint's feastday, it is referred to for the first time as late as 1681, The shamrock was used as an emblem by the Irish volunteers in the era of Grattan's parliament in the 1770's before 98 and The Act of Union. So rebellious did the wearing of the shamrock eventually appear, that in Queen Victoria's time Irish regiments were forbidden to display it. At that time it became the custom for civilians to wear a little paper cross coloured red and green.
Now Ireland is with
Our sustenance is
John Bull he boasts
and he laughs with scorn