Posted: 28/06/2013 at 17:12
When they do flower, you can use this site to identify them based on colour of the tepals, the colourof the stamens, the time of flowering and that will give you their pruning group for future years. There is pruning info on the site.
In the mean time, to encourage them, give them some specialist clematis food granules plus an instant tonic of liquid tomato food.
Generally speakig, the large flowered hybrids (group 2) flower in May and June an dthen again in late summer if they've been given a light prune to remove spent flwoer heads and a good feed. Group 3 clematis flower in mid to late summer so haven't yet got going. These are the ones you cut right back in spring.
Group 1 clematis only get pruned when you need to keep them within bounds or renew vigour. This group includes early spring flowering clematis that flower on old wood but also things like the tanguticas which flower in mid to late summer on old wood. You can't really expect any flowers this year if your 5 included one or two of these.