To begin with, the clematis that was planted originally is a type III clematis that generally does need trimming back on a yearly basis. If it is not pruned yearly, the existing stems will get woody over time and any flowering that happens will happen higher and higher on the new wood that is produced each year. Perhaps that was the cause of the diminishing blooms this past year. In addition, it may be suffering from water, sun, and nutrient competition if it is planted in an area where there are large trees and other shrubbery. Any clematis planted in these types of conditions will fail to thrive unless special attention is given to its water and nutrients needs (can't do much about the sunlight). Perhaps with four of the trees removed, this will remedy the light situation in the coming years.

Since you are interested in clematis that don't need pruning like the Comtesse does, I have consulted several books that I have and am providing a list of type II clematis that are listed as being able to tolerate shade. Just realize that it is difficult to determine how much shade on a quantitative scale that they require to actually flourish but at least you will have some names of varieties to try since trial and error is going to be your best bet to determine which, if any, will work in your location.

From "Simply Clematis" by Edith Malek:
Asao
Barbara Dibley
C. W. Dowman (never heard of this one)
Carnaby
Charissima
Dawn
Fairy Queen
Gillian Blades
Josephine
Lincoln Star
Louise Rowe
Nelly Moser
Otto Froebel
Peveril Pearl
Pink Champagne
Proteus
Scartho Gem
Silver Moon
Wada's Primrose

From "Clematis for Small Places" by Raymond Evison:
C. alpina cultivars
C. macropetala cultivars
Veronica's Choice
Alabast
Angelique
Cezanne
Chantilly
Clare de Lune
Dawn
Fujimusume
Guernsey Cream
Ice Blue
Silver Moon
Twilight

Having multiple books on clematis I could continue on but this should give you something to start with.

Perhaps someone who gardens in a similar situation as yours will chime in and give you some real life choices as well. Good Luck!

nckvilledudes:
Thank you very much for your very helpful assistance. We do cut back our clematis yearly, we use a drip irrigation system, and we do use organic fertilizer to assist with nutrient needs. As you can see in the picture below, however, they were not very happy last year.

I will certainly take a look at the plants you have listed. A friend also suggested Alpina or Mrs. Cholmondeley.

Thanks again!

Here is a link that might be useful: {{gwi:574262}}

The plant appears to have an issue with mildew. It may be partially due to an air circulation problem or lack of enough sunlight. Try spraying it proactively with a fungicide next year when it emerges and then intermittently throughout the growing season. The mildew may be affecting its blooming ability.

Ok, will do if we decide to keep them. Thanks again.

No problem, glad to be of help.

I never had that problem until I planted some Type IIIs and now my IIs are getting it as well. Some of them were ten years old. The leaves didn't drop off most of them either. They look awful, worse than bare stems.