Posted: 19/05/2015 at 18:23
I wouldn't put a clematis in a container that small. They're hungry, thirsty plants and you'd struggle to keep it happy. Better to stick with smaller plants which will cope, and you can move into a sheltered spot over winter if you have a really cold spell. Things like aubretia, which will cope with drier conditions but are hardy, would be ideal. Trailing ivies, small bulbs, dianthus and small hebes would also be fine, and pelargoniums for summer will also do well. If you have an idea of colours and types of plant you like , you'll get more suggestions. You'll still have to be vigilant with food and water.
If you really want a clematis, and can't put it in the ground, get a big pot to put it in and position it against the wall.