Homer, Niobe can be treated as a type II or type III clematis. That means that you can either trim it back each year or not. If you do, you lose the early flowers, but you will just get them later in the year.

In my NC zone7a garden, quite a few clematis at this time of the year develop very dark brown crunchy leaves. The heat and humidity usually do a number on them and the lack of rainfall this summer hasn't helped. I have noticed however that if I cut the browned out parts off, that the interior of the stems are still green. This indicates that the plant is still very much alive and will survive. I however can't bear to look at brown crunchy leaves so I tend to cut them back when this happens. If you keep them watered and fertilized well now, they will often come back out with new foliage and bloom again in the early fall.

Another thing to consider is that your clematis might have clematis wilt. If that is the case, then remove all of the dead foliage and discard it. Do as above as far as water and fertilizer and the clematis should come back--it might not be however until next spring.

One thing to remember is that all clematis should be planted several inches deeper in the ground than they were in their original pots. This buries dormant nodes that can allow the plant to resurrect itself if it should get wilt, trimmed back accidently with a weed trimmer, or if an animal gnaws it off.

Another thing is to make certain that the plant does not sit in water. Clematis like access to lots of water, especially in the summer, but they don't like to sit in it. It can lead to root rot.

Niobe can do just want you explained in zone 5 also. It is normal for the weather we are having. She will be fine & next season first thing you will see her vine as nice as can be. I have 3 & they can suffer this time of year but always come back in the spring & look brand new.

Nice to know that us southerners aren't the only ones with the dreaded brown out phenomena!

One thing to be aware of about Clematis is that they are almost impossible to kill. If you think one is dead, trim it back and leave it alone. It might take a year, or even two, but it will invariably come back. I had one that 'disappeared' for two years. I went to dig up the roots to plant something else in its place and there, deep down was the Clematis with two lovely, healthy roots coming up. I quickly covered it up again and it has rewarded me with dozens of flowers this year. So, be patient!