Holly (the plant) is cultivated these days for the principle purpose of being used as decoration at Christmas time. It is an evergreen and has therefore become symbolic of the everlasting love of God, just like the circle of the Advent Wreath. The red berries have become symbolic too and in a decidedly agonizing way.
The red berries of the holly are, on the Advent wreath, symbolic of the blood of Jesus Christ: blood that was spilt at his passion, those events leading up to and including his death. But don’t pick those berries off just yet; it is important as we listen to the nativity stories to keep Easter in our minds too.
The writers of the Gospels are not presenting a play-by-play account of the events surrounding the birth of Jesus Christ. They knew the whole story and the things they chose to include and the way they chose to tell the story was to remind us of the whole story. They wanted the listeners to be reminded at every turn that the birth they are hearing about is that of Jesus, the Christ.
This is the birth of Jesus, the Christ, Messiah, the Son of God, and the Light of the World. This is the one who taught and healed. This is the one who preached and forgave sins. This is the one who challenged religious and political authorities. This is the one who journeyed the countryside and entered Jerusalem during the Passover Festival. This is the one who was arrested, sentenced and crucified. This is the one who was resurrected and calls the whole world to love and justice.
Everything in the Gospel accounts of the birth of Jesus, from lowly shepherds to Magi from the east, are there to connect us with the whole story. The holly berries, that is the drops of blood, on the Advent wreath function in the same way: to remind us that this baby will live and die and rise again, forever proclaiming God’s love.