It is the Irish national holiday and one of the public holidays in the Republic of Ireland (a bank holiday in Northern Ireland); the overseas territory of Montserrat; and the Canadian province of Newfoundland and Labrador. In the United States, Australia, and rest of Canada it is widely celebrated, although not an official holiday.
It became a feast day in the universal church due to the influence of the Waterford-born Franciscan scholar Luke Wadding, as a member of the commission for the reform of the Breviary in the early part of the 17th century.
A common practice among gardeners is to plant at least one potato, no matter how cold the weather, on St. Patrick's Day. This is done in order to ensure a good harvest for the coming year. Some speculate that this may have arisen from the Irish Potato Famine.