buyorsell888 is a good source of information for you. She will be along and answer your question here or if you're in a hurry you can email her from her page.

Here is a thread that was started with recommendations from forum members.

Julia

Here is a link that might be useful: Clematis Sellers

Julia's thread lists all the clematis sellers, not necessarily the recommended ones. The three I use most are Brushwood Nursery, Silver Star Vinery, and Hummingbird Farm. Joy Creek also has an excellent selection.

My favorite sellers are the same as those listed above by nhbabs z4b-5a NH. To answer the OP's original question, Joy Creek is the only one I know in the general Portland, Oregon area. Perhaps others who live closer to the Portland area will chime in with suggestions for where they buy clematis locally.

I have purchased several over the years from Silver Star Vinery. They are a super place to buy from, The plants are nice sized, packaged very well, are sent at the right time for your zone, & grow nicely!

I have not had to resort to buying online except for one shipment. I have more than sixty Clematis.

You can find Clemmies just about everywhere here in Portland for reasonable prices. I've even gotten really nice ones from Fred Meyer.

Joy Creek is the most expensive in the area but does have a large selection. Every retailer should have at least a dozen to choose from or more.

Nelly Moser is a common one that is shade tolerant. You can usually find her just about anywhere including big box stores though I never buy there unless in bloom as labeling is terrible.

You can find Clemmies just about everywhere here in Portland for reasonable prices. I've even gotten really nice ones from Fred Meyer.

LOL!! That's because the same supplier provides clems to Fred Meyer as well as all the area retail nurseries :-) They just usually pot them up differently and sell them at a different price point due to volume. But they are all coming from the same place and of the same quality.

Those with different colored bars or stipes on the petals - like Nelly - are usually listed as more shade tolerant. As is the common evergreen clematis C. armandii and the spring blooming species alpina and montana. Most other clems would prefer quite a lot of sun. Too much shade reduces flowering.