Diseased branches are the first to go
Most climbing roses bloom at least twice each growing season: first on older branches and then on the current season’s growth. Pruning them while dormant in mid- to late winter will encourage plenty of late-season flowers. I like to begin my pruning by removing as much foliage as possible from each rose. This helps prevent disease by removing dormant fungal spores and allows me to see the rose’s branching structure as I prune. Once I can see what I’m dealing with, I remove any diseased, injured, or spindly branches, cutting them away flush with the cane from which they emerge. If any of the older, woody canes have failed to bloom well during the previous season, I will prune them off, too. Any canes that have outgrown their support will get a preliminary trim to set them back inbounds. I will also remove any crossing or awkwardly placed branches.