Answer: If you really renovate your climber you'll lose some blooms this year. Climbing roses bloom on lateral, or side shoots, produced along the canes. Begin by cutting back any dead or diseased canes. To thin the planting out, remove some of the older canes by cutting them down to ground level. The remaining canes will be the basic structure. (During the dormant season these canes can be cut back to 2-3 buds.) It's difficult to predict how much growth your pruned climber will put on this year - it depends upon the vigor of the rose type and on the weather.
There are many books on the subject of rose pruning and you may want to read a few before tackling your climber. One that's especially well written is "Roses for Dummies" published by IDG Books (ISBN# 0-7645-5031-4).
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