Adding plants that can survive the winter (1 Viewer)

I live in a townhouse condominium complex with a deck that looks up a hill to trees about 40 feet away. I have 4 feeders:

(1) mixed seed, (2) nyger seed, (1) suet

I also have a heated bird bath.

I have a few small potted plants which seem to attract the birds and make them more comfortable. For the fall and winter, I wanted a tallish evergreen type shrub or tree that would provide a bit of cover and make the deck look more natural. I settled on a Norway Spruce and planted it in a large plastic pot. So far, so good. The birds haven't let up at all and the sparrows, white breated nuthatches, chickadees, and tufted titmice action has probably increased. Any other suggestions on plants/shrubs/trees that can survive a New England winter outdoors without being planted in the ground?

I believe that the important thing is to ensure that the pot does not freeze solid: which is a very real danger. You might need to lag it with something to protect it from the worst of the cold.

Other than that, I think that provided the tub is big enough, there should be few problems.