Clematis can be moody. I have 5 of them against a tall fence. Each year all the clematis are "nice," but every year one really outdoes itself. This year is good old Perle d'Azure's turn. The plant is really magnificent. Perle got the same treatment as all the others -- a good load of manure at the first of the season -- but for some reason it really is strutting its stuff. The whole section of fence is aglow with blue. If you ever are thinking of replacing an underachieving clematis, wait a year. It just may surprise you.