One thing that has surprised me about Christmas in Denmark is the Jul Hjerte, or Christmas heart. It is an ubiquitous symbol this time of year, and something you don't see much of in the U.S. Perhaps it's because Americans strongly associate the heart with Valentine's Day, a holiday that is barely acknowledged (although increasingly so) in Denmark. But I have to say that I like seeing the hearts all over.
Another uniquely Danish holiday decoration is the paper star. Strips of paper are used to weave these intricate stars of all sizes and colors. Alas, I did not make these beauties.
Other common Danish Christmas motifs include mushrooms, animals, gnomes, and yes, Santa, or Julemand in Danish.