Posted: 22/07/2015 at 10:01
It is unwise to mix clematis from different pruning groups in one planting place as their pruning requirements to keep them healthy and flowering are so different.
If you want it to look good all year either go for evergreen honeysuckle or variegated ivies or the winter and spring flowering forms of clematis such as cirrhosa or armandii.
Another alternative is to paint your trellis so it looks good when bare in winter and then grow a mix of either group 2 or group 3 clematis. personnaly, I would suggest the group 3s as they are simply pruned back to about 9" in March, fed and then they regrow and flwoer all summer and just need training in as they grow.
They will lose their leaves and become a woody tangle in late autumn and can then be cut back to tidy them up but your should then mulch the crown of the roots to protect them from frosts.
Sunset, Princess Diana, Blue Angel, Betty Corning (scented), Caerulea Elegans, Huldine, Little Nell, Crystal Fountain and clems from the viticella group such as Etoile Violette will all perform well and be very hardy.