You'll need to tell us how old it is, and whether it gets enough sun...both could be a reason for not flowering.

mine flowered late last summer not this early.
it just seems to grow very fast then flowers later, here in glasgow anyway.

Hey thanks guys plants at least 3 years old the were in situ when I bought apartment and I haven't looked at them til now only know what they are cos there labelled, there are 2 each in pots (no garden) and they have been in shade I have not seen a flower yet

They need sunshine, Jabo - they won't flower in shade, and they're not fully hardy, either. One of our members in Berkshire lost his last winter.

Usernut is right - mine flowers in late summer and carries on until the frosts stop it. I cut it back by at least two-thirds in the spring, or it tries to take over the trellis AND the field behind us! lol.

Can you move yours into the sun?

I had no idea how beautiful it is will move pots to a more sunny spot is there anything else that I can do to help them along this year?

Feed them with a handful of blood, fish and bone around the roots, and water it in, or diluted general plant food. Yes - I totally agree - when I revamped the back garden, that was the climber I wanted for the centre of the trellis, and it's a star performer. :-))

Thankyou so much I have just with fed with miracle grow but will get blood and fish bone, it is bit woody and shrubby looking should I re pot and tie on to trellis it has been about 2 ft high for the last few years also just planted jackmanni clematis thought it would look nice with the white can't wait for summer ...

I'm amazed that it's so small!!!!! Mine shoots out yards when it gets going, and attaches itself to the trellis - i don't need to tie it in.

I think yours may well be starved in the pot, and restricted, so yes, try repotting into a bigger pot. No chance of planting in the soill is there?