Shamrock

No — luck belongs to the four-leaf clover. Send ☘️ for Irish roots or St. Paddy's celebrations; send 🍀 when you mean fingers crossed — a test, a ticket, a new job. The shamrock's job comes from the legend that St. Patrick used its three leaves to teach the Trinity, the Christian belief in one God as Father, Son and Holy Spirit.

Did St. Patrick invent the shamrock?

No — it was a plant in Irish life before becoming an emblem. A 1571 herbal, a book about plants, says Irish people ate shamrock. In 1681 an English traveller saw shamrocks worn on St. Patrick's Day. By 1726 botanist Caleb Threlkeld called it Ireland's national symbol, recorded the Trinity story as a current tradition, and grumbled about people “wetting the shamrock” — drinking to the saint.

The leaf travelled with emigrants. In the 18th century, Irish communities in North American cities used shamrock pictures and green where the plant didn't grow. In the 19th century, Irish-American St. Patrick's Day parades became a way to claim a public place, so ☘️ covers both the saint's day and broader Irish heritage.