Climbing hydrangeas are something of a patience plant -- they're notorious for taking their time in getting established. I've known some gardeners who have given their plants perfect care, and it still took seven years to bloom for the first time. The good news is that once a climbing hydrangea is established, it makes up for it.
The vines put on wonderful growth and bloom beautifully once they get settled in your garden -- and most gardeners agree that they're worth the wait. That said, the one thing I can recommend is that if you prune it, wait until late June or early July to do so. The plants develop their flowers on last year's branches, so if you prune in fall, winter, or spring, you could cut off the buds before they have a chance to open.