I planted a clematis in my garden late in summer last year in a very sunny location. It grew well, is supported by a trellis and did some blooming last year. As required, the roots are kept cool by a generous layer of mulch. This spring it started growing very profusely, sprouting several shoots and very quickly made it all the way up to the top of the trellis, creating a thick layer of foliage. However, up until now it never had a single blossom, and I can't really see any buds anywhere. What is wrong here? Your advice would be much appreciated.
Most likely your Clematis is just busy establishing it's root system and will reward you with years of flowers in the future.
Over fertilizing is a common mistake and will inhibit flowering.
This article will help you.