"Palm Sunday is the beginning of Passion Week. "
Jesus entering Jerusalem on a Donkey. Unknown publisher of Bible card. c.early 1900s
Public DomainJesus entering Jerusalem on a Donkey. Unknown publisher of Bible card. c.early 1900s - Credit: Wikimedia Commons

Palm Sunday always falls on the Sunday before Easter in the Christian calendar.  It marks the occasion of the triumphant entry of Jesus into Jerusalem before his Passion.  It was, and still is in some countries, the tradition to distribute palm leaves (or other native flora) to the assembled worshippers.