Flocking refers to artificial snow, which is a popular decorative element sometimes added to trees to create the look of a winter scene in your home. While there are options out there that are pre-flocked for your convenience, you can purchase faux snow separately to create a custom look on your tree.  FYI: Darin also shares the flocking can lead to yellowing when placed in direct sunlight, so be sure to pick a shady spot for your flocked tree. Also, flocking can be quite messy!