By Freeasabird
Oxfordshire,
United Kingdom 
just read your advice Bamboo about not pruning Nelly Moser clematis. So this is where we are going wrong? We have a large pot near the front door, in the first year of buying about 4 flowers. Second year masses of foliage but no flowers. Third year [this year] poor foliage and no flowers. We have pruned to instructions that came with it to chop it down to a third of height in early FEB.We have also fed it at the right time [Ithink!]We were going to get rid of it this year until I read your message.
17 Jan, 2012
Previous question
Your problem may be twofold - the containment of the pot and incorrect pruning. These can be pruned if they need to be restricted, but what happens if you do is that the early, large flowers are sacrificed - but then you should still get the later, smaller flowers. As you're not getting even those, I suspect it may need repotting (possibly into a larger pot, should be 24 inches deep by 12 wide as a minimum). Feed bi weekly with something like Miracle Gro general purpose powder, mixed as per instructions in water, ensuring that the compost isn't bone dry when you apply it, from mid March through to mid July. I don't know whether your plant is in full sun - if it is, the pot will need shading from hot sun, particularly between 11 and 3 p.m.
17 Jan, 2012