It definitely needs its own trellis if you care about the tree. I don't think it would be a symbiotic relationship. Passion fruit is very vigorous. I have two vines on their own trellises along my fence, but it would have been better to put in a large trellis for them because they grow onto my neighbors sides. Also, to grow fruit you need to do hand pollination. High up in a tree you can't reach the flowers to pollinate.