It is assumed, however, that St. Patrick knew about the significance of the shamrock in other religious and pagan traditions, and may have incorporated it into his explanations and teachings. The Druids, ancestors of the modern Irish people, believed in the holiness of the trefoil because of a sacred symbol formed by its three leaves. The number three figures prominently in other religions, too. To Christians its leaves form a cross and serve to represent the Trinity. It was thought that followers of St. Patrick wore a shamrock on his feast day.
Legend also has it that snakes avoid trefoil, and that it is a remedy for snake and scorpion bites.
The Druids believed that a four-leaf clover could help in spotting witches or other demons. Yet others feel that finding a four-leaf clover bring good luck and fortune, not just on St. Patrick's Day. However, botanists believe that if a young clover leaf is damaged or exposed to certain chemicals, then it produces a four-leaf clover. Don't spend too much time looking for luck in fields of clover. It is as closely associated with St. Patrick's Day as red is with Valentine's Day.