Brushwood Nursery in GA says they ship to the continental US. They start shipping in February.
http://www.gardenvines.com/shop/

Joy Creek Nursery says they ship to CA.
http://www.joycreek.com

Both these nurseries have good reputations. I have ordered many clematis from Brushwood and have always been pleased.

Joy Creek is located right outside Portland, OR, so obviously they ship anywhere along west coast. Also, Silver Star Vinery, another excellent mail order source, is located In southwestern WA.

Because CA is such a highly agricultural state, there are some restrictions about what can be imported and from where......like grapes for example. But there shouldn't be any concerns regarding reputable mail order sources shipping in approved plants. Plant Delights is another excellent mail order nursery that ships to CA and carries clematis.

Silver Star states on the website that she doesn't ship to CA which is why I didn't include her.

Ahhh.....she is located right in the middle of WA state's wine country so that may be why. Dare not contaminate those valuable grape vines in CA with some dreaded foreign pathogen :-)

Although I don't do too much mail order, I've ordered both from Joy Creek and Brushwood as well as non-clematis plants from Plant Delights and have been extremely satisfied with the results.

Thanks! So many choices now to decide from.

Rick