In article , Charlie
Pridham writes

Ones that have done well in adversity for me are, Abundance, Alba Luxurians,
Sodertalje, Prince Charles, Minuet, Madam Julia Correvon, Margot Koster,
Vanessa & Huldine (both later) and of course Polish Spirit. There are loads
more! I like these because you can cut them away in winter and the window of
opportunity for doing so is from November to late April. Plus they flower on
mass in the summer (late summer in the case of Huldine and Vanessa) and
never affect the flowering of what ever they are growing on. Nick has
suggested the Alpina sorts but they for me don't perform as well, seeming to
not like our soggy winters (although I have a few and like them)
Do try, you will find as I have that Clematis perform much better through
plants than on fences anyway.

What about slug-resistant ones? I want to get some alpinas in the garden
for the early flowers, but I've failed completely in the past because of
slugs chewing the new shoots as soon as they appear. I've now got two
growing in the greenhouse that I'm going to try and plant out when they
are about 6ft and hopefully less attractive to slugs.

Montana, orientalis, armandii, jouiana all do OK, but they're all late
(except armandii), and I don't prune any of them, so they have high up
growth on tough stems. And I have an integrifolia which has now made it
into the top of a rowan and is beginning to take off. But I really would
like to get some early ones settled.
--
Kay
"Do not insult the crocodile until you have crossed the river"