Morning Glories and Passion Fruits are both annuals in your zone.

Clematis are perennials but they take several years to get going. They are not instant gratification plants.

They work fine in containers, but depending on where you are, they might not overwinter well. The western exposure, however, is fine.

I would go for an easy care viticella like Emilia Plater, Etoile Violette, et al. They are also more likely to survive winter left outside in a pot.

Evey, owner of a website that specializes in small clems for containers, sent beginner-me a very informative reply to my questions. The website says they are sold out of everything right now but there's lots of background info on zone, sun/shade, & height. Then the super experts in this forum can help you make a final choice! I bought a nice Princess Diana from them to plant in the ground, but Evey grows it in a container: http://www.simplyclems.com

Thanks everyone.

River - that's a great site. It seems it is too late for me to get the one I want, so I will wait until next year. It gives me time to learn more about them any way.

Thanks again!

You can buy Clematis at many locations other than that site.

Just an FYI: The clematis at SimplyClems are not what most people would consider garden ready, but the plants are very healthy.