Why are red and green considered Christmas colors?

(WHTM) — The Christmas holiday isn't just about giving gifts to those we love — it's also about getting into the spirit, which many people do by decorating. But have you ever wondered: Why are red and green considered the primary colors of Christmas?

According to Southern Living, Celtic people centuries ago admired red-and-green-colored holly plants for surviving the winter season.

These ancient Celtic people believed that holly plants kept the Earth beautiful during the winter...