Trish, the NW experienced an unusually dry summer followed by a very wet and blustery winter. Without a closer examination, I'd guess your armandii was experiencing some drought stress going into fall and winter. Stressed evergreens of any kind are much more vulnerable to winter damage than those that are perfectly healthy. The numerous windstorms and sharp cold spells we had are likely contributing to the brown and dead growth you see now - armandiis do not like exposed sites and heavy winds. Mine and others in the area are on the verge of flowering right now and immediately after flowering is the best time to cut these back. Wait until the middle part of next month and cut back hard. Fertilize with rose or tomato fertilizer and pay close attention to the watering during the summer. A liberal organic mulch of compost at the base will help to retain soil moisture. If all is well, it should resprout and grow rapidly. Armandiis are vulnerable to a (suspected) virus that is similar in form to anthracnose. If you see a repeat of the same symptoms after providing the above care, you may want to consider replacing it.

It would not be something I'd advise :-) Of all the clematis I have grown, armandii is one of the least suited to container culture. Big vines typically translate to big root systems and armandii has the largest root system of any clematis I've worked with -- far larger than what a half barrel would easily accommodate. I'm sure you could keep it in a container for awhile but a restricted root run will result in a naturally dwarfed plant and so I would expect stunted growth and most likely lackluster flowering. And there would be a need for regular root pruning -- a lot of work with a vine like armandii. And by moving it to "a bright window in the winter" I assume that means the plant is not winter hardy in your zone? When would you be able to move it outdoors? It has a very early bloom season that can be affected by hard frosts in cold climates. And it would outgrow a 5' trellis in a single season. Can you explain where you are located and maybe there's a way one can work around these restrictions. But on the surface, it doesn't strike me as a good plan....sorry :-) Have you considered a variety like xcartmanii 'Avalanche'? This is also an evergreen selection with a profusion of early flowers much like the white form of armandii ('Snowdrift'), but it is a much more compact plant with a much more condensed habit (8-10 feet compared to 25-30') and with nice, smaller, lacy foliage too and is far better suited to being grown in a container.

I would trim and fertilize. This crappy wet gray weather we are having is likely at least partially to blame.

From personal experience I feel sure your neighbor would love wisteria too. So beautiful and so easy to grow. Mine could reach across the 7-foot gap between our house and garage within two weeks, greeting us after each summer vacation with a lovely dappled-shade passage. More than once friends were surprised when the vine shot seeds at them, which was fun to see, but I really appreciated it for the way it cobra-squeeze destroyed the old wood arbor my husband didn't want to work on, giving me an excuse to replace the posts with metal 4x4s with decorative heavy metal brackets. I'm not sure anything can match the gift of bamboo, though. I once appraised a house in an old neighborhood belonging to an elderly lady. After her husband died and son moved to New York, it got so lonely it moved into her garage looking for her, then swept across their rear yard to visit four adjoining elderly neighbors and their yards, before finally finding her and moving into her rear porch and laundry room. About that time her son came to visit her, instead of vice versa, and I got called when he decided she needed to leave before it tried to join her at the kitchen table. BTW, the home, garage, and retaining walls between all these hillside properties were total losses, with all requiring extensive bulldozer work, but for economic reasons only the property for sale and one other actually got the 40'-tall bamboo and its underground structure bulldozed out... Buried a house and contents (?!) definitely tops anything here, although I guess the GaEPA problem-solver (of interfering with business as usual apparently) official is mine too. In my case I do happen to know there's not even a shed or old bed buried in this area, just our usual light clay piled up behind a short retaining wall. A bit of a wander from Clematis armandii. On shopping I found that Chalk Hill Nursery has closed. So sad. That was the first place I automatically looked. I also want to try a solid-cream (no speckles) Clematis cirrhosa for winter flowers, but I'm going to have to find them at some other nursery, after it opens in spring apparently.