Thanks to Garrison Keiler and the Writer’s Almanac for explaining what the shamrock frenzy is all about.
“Today is St. Patrick’s Day, a feast day honoring the patron saint of Ireland. St. Patrick’s Day was originally intended as a holy day to observe the arrival of Christianity into Ireland. St. Patrick himself was English, not Irish. He was born into an aristocratic family, but was kidnapped and taken to Ireland. Eventually, he escaped, went home, became a priest, and returned to Ireland to convert the natives to Christianity. According to St. Patrick’s Day lore, Patrick used the three leaves of the shamrock to explain the Christian holy trinity (the Father, the Son, and the Holy Spirit) to the native Irish, and the shamrock is now, along with the color green, one of the major symbols of the holiday.
Until fairly recently, St. Patrick’s Day was celebrated only as a religious holiday in Ireland. People were given the day off from work; they went to church, and then they shared a big roast dinner with their families. The pubs were required to remain closed that day, so no green beer — or beer of any sort, for that matter — was allowed to be served in public. It was the Irish in America and Canada that turned the saint’s day into the full-blown party that it’s become. The first St. Patrick’s Day parades were held in America during the 18th century, as a show of loyalty to the mother country and a way to call attention to the plight of working-class Irish immigrants. Boston organized the first parade in 1737, and New York’s first was in 1762. During the Revolutionary War, General Washington issued a proclamation in 1780 that gave Irish troops the day off for the holiday.
Parades remain a large part of the day’s celebrations, and New York City’s is the largest in the world, with the 69th Infantry Regiment leading 150,000 marchers up Fifth Avenue. In Chicago, they dye the Chicago River green every year. The custom began in 1962 when parade organizer Steve Bailey, also the head of a plumbers’ union, noticed how a dye used to detect pollution in the river turned a colleague’s overalls green. He thought that it would be a good idea to use that same dye to turn the entire Chicago River green on St. Patrick’s Day, and a tradition was born. In Dublin, the parade has grown into a five-day festival and attracts millions of people every year. Consumption of Guinness stout more than doubles on March 17; around 13 million pints will be imbibed worldwide today.”