Maybe you are over doing the feed. I have never fed mine and they flower each year. Or are you pruning them when you shouldn't?

Camomile,
You could be right about the overfeeding - It perhaps has received too much to try and make it flower. I have also decided not to cut it back this year.
Friends of mine feed theirs with plenty of manure etc. and all theirs flower like mad.
Its so disappointing as always so reliable.

This one's a prune group 2 - which essentially means no pruning, other than nipping off any dead parts, and, if you want, cutting back to the highest, or top, pair of buds in February/March. As its up in a tree, that might be difficult, so I'd leave it alone, but if you cut it too late or by too much, that might explain the problem.

I'm with Bamboo on this. I doubt the problem is over feeding...they are very hungry plants generally. More likely to be pruning. I always say to my friends remember...no clematis 'needs' to be pruned. We ony do it to enhance the look of the growth and so that the flowers are not too high up to appreciate.

Bamboo and Cottagekarer thank you both so much. I did wonder if I was cutting it back too much. The trouble was loads of ivy growing into tree so I just cut back the lot but now the ivy is out the way I will leave the Clematis as you both suggest.

:) HOpe it works! I find group 2's so unreliable up here in Scotland. I tend to avoid them and go with the group 3 vars. But I did have Josephine once...she flowered for the first year, but not so much after that. Probably a similar issue as she was tangled up with other climbers on my fence and i probably pruned too much off in the autumn clear up (by pruned off I really mean accidentally hauled it down with everything else!). Good luck Linmar, it's a beauty!