Can't really help you too much yet, but I'm trying to winter sow some passion vine seeds. I'll let you know if anything happens (which I'm guessing won't be for a while yet). Hopefully someone will offer some good advice.

I might point out that these are native passion flowers that grow wild in my pasture, so they do propigate on their own. I expected it to be easier than this though.

People with successful vines that you admire might welcome you to dig up volunteers, once they get going in spring. That's how I got mine.

I grew PF Foetida from seed a couple of years ago. I planted them in July, I had plants appear finally after I'd given up on them in late winter. I planted them outside in late March.

I'm growing 2014 seeds on paper towels right now. Yikes!