Yes it will grow horizontally.

Passionflowers have a tendency to climb and then branch out. I have mine in the ground and my irrigation is set for twice a week. When you are trying to establish them, from pot to ground, I find here in Florida 3-4 times per week, until they put out new growth or don't wilt in afternoon sun. Good luck with your butterfly garden!

Thank you alot Emmett and Morning! ^__^ Good day to ya! I'm reading, on Google, that mine can grow 20-30 feet. Really hope I don't run outta space for it. The Passion Flower I have only, it seems, to have its flower 1 day then it shrivels. Oh no! I hope mine doesn't wilt in this sun! :-O :-( What do I do if I see some wilting?

Passionflowers generally close up after one day. If I see mine wilting I give it some water. I find after they become established they don't need that afternoon drink.

Kristy, not sure how cold it gets where you are but you may have to protect this this winter. My understanding is p.edulis doesn't like freezing weather. It will handle the heat if you keep it watered properly.

Aaah okay. Too bad only 1 day. I adore how different/special/unique the flower looks. And it doesn't freeze where I live. Rofl When I'm "training" it what part of the plant do I use ties with? The tendrils? The stem? Thank you guys! Can't say that enough.