Question
Hi, I live in Salt Lake City, Utah and have the exact same question about evergreen planting in containers for outdoor use on a balcony - only I am in a much colder zone than Portland, Oregon like your previous questioner. Which evergreens would grow 5-7 feet tall and be hardy in my zone?

Answer
Sunset Western Garden Book says, you are in zone 2. So I looked for evergreen shrubs for your zone that can be maintained at around 5 to 7 feet.

Common Boxwood will get up to 5 feet.
Japanese Holly  
Dwarf Chinese Holly
Juniper "Blaauw"  or "Fruitland" or "Golden Armstrong" or "Holger"
Japanese Privet Or Vicary Golden Privet
Japanese Photinia
Thuja American Arborvitae
Canada Hemlock
Viburnum burkwoodii

Most of these evergreens will, if not pruned, grow to a much taller height. But, plants grown in containers, tend to grow much slower and shorter, then those grown in the ground. You will need  substanual containers to hold the large plants. Gradually pot the small plant, you start with, into the next larger pot, and then to the largest. This method will ensure the roots are not left dry by the container being too large for the root ball and the water pulled away from the roots to the sides of the container,leaving the roots dry. In severe weather, some protection from freezing, and wind, or sun damage would be recommended. Wrap in burlap, or something to shelter them.

bakerplanter