Ireland chose it as their national emblem because of the legend that St. Patrick used the shamrock to illustrate the doctrine of the Holy Trinity. The doctrine teaches the unity of the Father, Son, and Holy Spirit as three persons in one divine Being.
St. Patrick demonstrated the meaning of the Blessed Trinity by picking a shamrock from the grass growing at his feet and showing it to his listeners. He told them that just as the shamrock is one leaf with three parts, God is one entity with three Persons.
The Irish have considered shamrocks to be symbols of good luck since the earliest times. In modern times, people throughout the world believe shamrocks symbolize good luck.
Today, I bought a Shamrock Plant at Walmart. The Luck of the Irish will be mine for sure.
MAKE IT A GREAT DAY!