It's kind of funny how I first started doing this. I was head gardener at an estate and I was pruning the yew and holly near the doorway. So that I didn't have to rake up the cuttings, I was just sticking them in the empty planters at the door. The client came out, saw the pots, and said oh how pretty! Those will look nice all winter! Uh-yeah-I meant to do that!
Solved my problem on what to put in the planters for the cold season!
Once Christmas trees and garlands arrive in the stores, I'll add some more greenery, but the holly and yew stay the longest.
i have tried putting boxwoods and pansies in planters for the winter, but you definitely have to keep up on watering for them to survive.