This is my own guess: I'd wait through the summer until the new canes have grown and are hardened off, and then in fall I'd cut out a portion of the oldest and most miserable canes, removing them completely and leaving a mix of old and new canes. If the remaining canes need shortening I'd do that as well. If someone comes along with more decided ideas and flatly contradicts what I just said I won't holler.
Melissa

Did you regularly cut older canes out during last 8 years? Roses need old canes to be removed on a regular basis. Similar to what you do to lilacs or other bushes. Different roses has different productive cane life. For example, long cane bourbons perform best when all canes older than 2 years are removed. Albas canes in my experience are ready to be removed after approx 3 years. Can be even after 2 years, depending on what look you try to achieve. Older canes help to support the new growth. So it works best to always keep some 2-3 year old canes.
The best time to remove old canes is early spring (before leaves grow). At this time you can see the bush structure and it is easy to make decision what to leave and what to remove. This will not reduce the number of flowers in spring flush. Other canes will bloom more with this kind of treatment. You can also shorten and shape other canes at that time, if you want. Again it will be only beneficial. There will be more laterals produced to give more blooms.
This is one of the old wife tales that roses like albas or gallicas should be always pruned after bloom.

Olga

Olga I didn't do that with this shrub and thats why I'm having problems now. In fact I seem to have a different mind set when It comes to once bloomers. I always do that sort of pruning with the repeat bloomers. I read a few articles about alba's and they said to leave them alone. But thats not working. I have several others that need canes removed or I'm going to be in trouble with them. Thanks for your input its a big help. Thankyou Melissa for taking the time to share your thoughts as well.

Mark

The difference between pruning repeat bloomers and once bloomers after blooms is that if you prune a once bloomer to half the cane length, there aren't many leaves to support the plant--so it will sulk! A repeater bloomer will also sulk if you lop off all of its leaves after blooming.

I find it best to remove the old canes in one of those momentary warm spells before winter ends. The plant won't put out new basals until it really warms up--and when it does the new canes will have a full growing season to get big.

Zack I grow mostly oncebloomers and my stratagy works for me. They grow laterals with new leaves in spring after late winter pruning, bloom their heads off and never sulk. Your experience can be different, we all garden in different conditions.
Olga

Thanks for your expertise, Olga. My KvD is fine, but my Alba Maxima isn't happy this spring and needs me to get tough and remove more of the old canes. Out with the lopper I go...

which one is KvD?

Konigin von Danemark.........

I had some grafted roses disappear and come out as root stock after about ten years.

Kaylah I'm happy to report they are all KvD shoots, looking very nice. I have some branching going on as well. Its really taking a turn for the good. :-) Its blooming great this year, nice big blooms......