Climbing hydrangea – my 2 year old plant has brown spots especially on the tips of the leaves. The leaves are also beginning to curl. This condition seems to be spreading upwards from the leaves at the base.
Sounds like your hydrangea could be suffering from a root rot. The fungi causing root rots are often common soil inhabitants that do not cause damage until the conditions are right to promote their attack of host plants. The link below will take you to a previous post on this issue. The post contains a link to a good article that covers the common diseases of hydrangea. I hope your climbing hydrangea recovers as they are truly beautiful plants.