Dwarf evergreens in container
You can grow evergreens in containers but keep in mind that sometimes the plants succumb to the elements during the winter. Use as large containers as you can. Keep the plants well watered until the soil freezes. If possible, move them to a more sheltered area for the winter - like a shed or garage where it stays around 30 F. The problem with winter survival is usually due to the potting mix drying out too much before it freezes or during thaws or when temperatures drop into the teens and below. Some folks bubblewrap their containers for extra protection. The tops of plants are able to withstand lower temperatures than the roots. http://www.chicagobotanic.org/plantinfo/faq/overwintering_evergreens_containers
Here is some info from the Chicago Botanic Garden.