Posted: 19/09/2016 at 13:05
Clematis montana can be a thug and grow far too big for most people so I would suggest you consider a couple of better behaved alpinas or macropetalas for early spring flowers. You could also try clematis cirrhosa which is evergreen except in severe winters and flowers in winter. Use this academic site to search for different types and info about flowers, pruning etc. - http://www.clematis.hull.ac.uk/new-clemlistsearch.cfm
The thing with mixing clematis is to make sure they are all in the same pruning group or life can get complicated. The above mentioned are all group 1 - prune only after flowering and in order to keep to size. Use this academic site to search for different types and info about flowers, pruning etc.
Plant them several inches deeper than they were in the pot and give them a good soak first. The planting hole needs to be at least 18"/45cm away from the fence so the plants aren't in the rain shadow and also deep and wide. Back-fill with a good mix of your soil with added garden or bought compost and maybe a handful of pelleted chicken manure or blood, fish and bone mixed in. Water thoroughly and then mulch with more compost to retain moisture. Give occasional liquid tonics of liquid tomato food and, every spring, a generous dollop of clematis food.
As they grow, train the stems out horizontally along wires stretched across your fence at 12"/30cms intervals.
Training an evergreen ceanothus will give you flowers later on. I would also suggest pyracantha as they are good for wildlife with their blossom and berries and shelter.