The reason we associate poinsettias with the holidays comes from an old Mexican legend. A young girl named Pepita was sad that she didn’t have a gift to leave for the baby Jesus at Christmas Eve services. Her cousin tried to comfort her and said that Jesus would love any present from her, even the smallest one. With no money to buy a real gift, Pepita picked a bouquet of weeds that she walked past on the way to church. (Other versions of the story say an angel came to her and instructed her to pick the plants.) When she got there, she left the weeds at the bottom of the nativity scene. All of a sudden, the weeds transformed into beautiful red flowers.
From that day on, they became known as “Flores de Noche Buena,” or “Flowers of the Holy Night.” – Reader’s Digest