what is the secret?

What is the secret to growing a vine that fills the bottom of the trellis? I have grown confederate jasmine and mandevilla and both of them shot straight up and then bunched at the top. Are you supposed to cut them back so they branch more? I will be planting a blue sky vine and a black eyed susan "sunlady" vine and I really want them to not be so top heavy. Any assistance will be very welcome. Also have many of you found the black eyed susan vine to be very invasive? I live in Ormond Beach, Florida I'm not sure if it's 9a or 9b.

I would pinch them before they get too tall, like at a foot. It should help.

I train them - go to the trellis everyday and point them where I want them to go.

The sectret: Fake vine.
Almost.
Full sun all the way around helps greatly, and like Brugie said, train it to branch. Some plants just refuse to do it. Others will not grow out anormal life cycle if they are trained. Trim back long, unbranched growth to a third or fourth bud.
I've learned to accomodate vines in whatever way they were designed to grow in my love for all things tendrilled.
K. James.

Pinching and training help alot. So does planting a medium-height bushy plant in front of or around the base of the trellis to hide the more sparse lower areas!

Good luck.

Erick