I don't know about "Susan Bingham," but many passiflora species don't begin to bloom until they are 2-3 years old. Also if the fertilizer you are using has high levels of nitrogen, that may cause vigorous growth at the expense of blooming. Myles Irvine's website below may be useful for answering your questions.

Here is a link that might be useful: Growing Tips

I would be patient - if it's a young plant it should bloom by the end of summer. 'Susan Brigham' is a rampant grower, so since it's only in a 5 gal pot I wouldn't bother fertilizing it. Also, I assume you're giving it plenty of sun?

Thanks for your replies to my post. I'll be patient and give this wonderful vine some more time. It's worth the wait. But to answer your follow up questions...I'm not fertilizing too heavily, since I heavily composted the soil mix. It's now in a large half barrel planter, and I'm gonna let it take hold there. It's still thriving with a lot of new growth and clinging well to a trellis support.

Here is a link that might be useful: Compact Garden: My personal site for Gardens for Small Spaces. Vines are a particular focus.