one of the reasons we wear green is because of Ireland’s nickname, The Emerald Isle. The green stripe in the Irish flag also played a role. Traditionally, the green represents the Catholics of Ireland, the orange represents the Protestant population and the white in the middle symbolizes the peace between the two religions.
The religious symbolism doesn’t stop there. St. Patrick is thought to have used green shamrocks to teach people about the Holy Trinity (God the Father, God the Son and God the Holy Spirit), another justification for greenifying everything.
Even though it’s less common today, blue has always been one of the St. Patrick’s Day colors. Early depictions of St. Patrick show him wearing blue, and the official color of the Order of St. Patrick, part of Ireland’s chivalry, was a sky blue known as “St. Patrick’s Blue.” The blue symbolism dates back to early Irish mythology, as Flaitheas Éireann, the symbol of Irish sovereignty (think Uncle Sam), was depicted with a woman in a blue dress. The first official association with the color blue was when Henry VIII took the throne and declared himself King of Ireland, making it part of England.
As time went on, the people of Ireland resented this arrangement. They rebelled, using St. Patrick’s shamrock as a symbol of their identity, making green the symbol of Irish culture. Although it’s hard to find St. Patrick’s Day–specific clothes that aren’t green, you can still celebrate by learning Irish words and phrases (like “Erin go Bragh” and sláinte) while wearing Irish clothes in the saint’s original color: blue!
The pinching rule on Saint Patrick’s Day
As we said, we’re pretty sure that Americans came up with this wear green or get pinched rule as Ireland doesn't go as full-force with the whole leprechaun stuff itself.
As the tradition goes, wearing green on St. Patrick’s Day is supposed to make you invisible to leprechauns. They will pinch you as soon as you come upon their radar if you don't wear green!