Can someone help me?

So when I plant it in the ground how long is the root radius? 5 feet?

Here's a photo

I don't have any experience with Purple Possum, but with Incense and an unknown volunteered passiflora, they have underground runners and will sprout up over 40 feet away! If I had to do it over again, I would keep Incense in a pot over a cement base.

Yikes! Does all passion fruit do that?

'Possum Purple' is a selection of Passiflora edulis, the soil mixture used above is fine. As Tim said above, watering, drainage and sun exposure are really important. After a couple of years the root radius can be 5 feet or more. This passiflora will not spread by root runners, only the species P. incarnata and P. caerulea and their hybrids will do this. P. 'Incense' is a hybrid of P. incarnata x P. cincinnata.