Posted: 29/08/2013 at 15:02
Stones hide slugs and snails which like to feast on new clematis shoots in spring so none of my 50 or so clematis has a stone in front of it. The more recent additions all get a clay plant pot with the bottom bashed out inverted over their stems to protect the base form my husband's slap happy hoeing action but shade comes from plants in front which also serve to hide any tendency to bare legs.
Clematis have thick fleshy roots which like a long, cool root run so a trough in full sun is not teh best place for them. I wouldn't plant one in any container smaller than 60cm (2') wide and 75cms (2'6") deep and then only facing north or east so the pot doesn't get hot and cook the roots.
Clematis are also very hungry plants so need the best compost and regular top ups of feed, both slow release clematis food and quick tonic liquid tomato or rose food to keep them growing strong and flowering well. They don't like to be too dry either so, if training up a wall, plant them at least 18" to 2' (45cms to 60cms) out and give them plenty of organic matter in their planting home then train them back to the wall. Water them generously at planting time and until established. You almso need to plant them at least 4" (10cms) deeper than they were in tehir pots as this protects against cleamtis wilt and encourages more stems to grow.