Hopefully Rachel will spot this thread because I gave up growing this
variety, It is not frost tender as such but seems a lot les robust than
other clematis and I would concur with the grow in Shelter advice.
growing
in a pot is fine and I would expect it to reshoot from below ground. In
the
mean time remove all dead and dying bits.

Do you mean it just dwindled?
If it doesn't prosper in Cornawall, then I wouldn't have thought there's
much hope for the rest of us!

Janet G

Its a plant that seems to like the quiet life! so a windy place like
Cornwall doesn't suit it, but also the lack of summer heat and lack of
winter cold don't help. But the main reason I stopped growing it was that it
didn't earn its keep, my plants have to provide me a living from cuttings,
it didn't so wasn't replaced :~) (it is hard to strike and has a high loss
rate growing on, hence its relatively high price) I figure if the person
selling the plant can't grow it, it doesn't give the customer much of a
chance!

--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collection of Clematis viticella (cvs)