This first is a basic red yucca (Hesperaloe parviflora), which lives in what can only be described as HARSH environs. It is on the corner of the building, on the 42nd floor, with ridiculous winds almost all the time. (The cement container has been blown off the plinth at least twice and needed to be replaced, though the plant has survived each crash.)
The arrangement below was in front of the Big House during the winter of 2010-2011, when we had extremely cold weather (and lots of snow by Georgia standards). The variegated boxwood did just fine (again in a really windy spot where it gets hammered by Northwest winds), and we replaced the cut things every couple of weeks. For some of the broadleafed evergreens like the magnolia, we sometimes use an anti-dessecant spray to prevent windburn, which is actually easier to find in northern states. The variegated boxwood is a standard container plant for us, but I don't honestly know how far north it is hardy.
This is the front entrance at Christmas 2009. We have since replaced most of the evergreen hedges with a softer look, because the arborvitaes and all that holly was really becoming oppressive in the grand scheme of things. At the holidays, though, you can't get a better look for a traditional Christmas decor. The corkscrews are Carolina Sapphire (Arizona cypress), which gives a great blue contrast to the dark green of the arborvitaes. Further forward, the mondo grass is evergreen for us (but an absolute bear to maintain year round). And before you ask, the boxwood gift boxes are artificial boxwood......sorry.....
Here's a closer shot of the corkscrews, which also shows the hellebores at the base. We regularly dig hellebores out of the garden in late fall to use in winter containers that are protected from really harsh wind. In the early spring, they go back into the garden. Lots of people have told me that they can't be moved, but I would respectfully disagree. They are "tough as nails" plants in my mind.
Pinus flexilis "Vanderwolf's Pyramid" lived in a container for two full years (in full sun) before going into the landscape. Here we used it with Pieris "Cavatine", pansies, prostrate rosemary and ivies.
As always, click on the photos if you want to enlarge them, and don't hesitate to ask if you have questions about specific things. I'm happy to share whatever I can.