Sounds like a good time for you to visit the California Gardening regional forum! Duplicating a Texas garden in SoCal may not be the most advisable plan but fellow local gardeners can give suggestions for replacement plants and appropriate garden practices. Ongoing droughts and waterwise gardening will be primary concerns, not to mention lack of a proper winter chill period. If clematis are well-suited, they can surely point you to the best sources as well.

The California Gardening forum is quite active - you should get lots of responses, not to mention make a bunch of new gardening friends.

Armstrong Nursery in Temecula sold me this lovely (but pricey) Pink Champagne Clematis - I'm trying it in a container, since we have a gopher I've not been able to discourage...

Here is a link that might be useful: Pink Champagne