I grow two kinds of figs in 15 gal pots and they produce like crazy. One was planted from a tiny cutting at the beginning of the year and it has about 20 figs on it now. Since you can prune figs to whatever size you want, you can even go with a small pot, I've seen them in as small as 3 gal producing figs. Of course, the bigger you go, the more figs you get.

As for passion fruit, the same thing goes. If you let it go crazy, it'll become a huge woody vine that takes over fences. Or you can trellis it up a pole and keep it small. Again, depends on your space and how much fruit you want. Hope that helps!

Here in urban z. 5, a friend's Sicilian immigrant father grew fig trees in their yard, and in the fall, he sank them down, horizontally into a deep trench and covered them w dirt til spring, when they were resurrected. Another friend here planted a passion flower vine next to her dryer outlet, and it lives on.

I am growing figs in 15 gallon containers, and they are huge. I let mine root into the soil, and have to chop off the roots to move the pot. These are very hardy plants in pots. I've got a couple in 3 gallon pots that seem to do quite well; not as many fruit as in the bigger pots, but much much easier to move.
Renais

This post was edited by Renais1 on Mon, Oct 13, 14 at 15:14

I bought 10 passion fruit seeds and intend to germinate them in small pots indoors this winter. I am going to build pots for them from wood. I plan to build a pot 18 inches in all directions and attach a 5 feet high lattice trellis across the back. To the bottom I will attach 4 rollers to allow easy movement. During the winter I will bring them into the house. They will make great gifts for friend and relatives.

I have 11 figs in small, one gallon pots. They were all about three inches tall at the start of this year, and now they are all spreading out and growing up from one to three feet. About half of them are fruiting. Figs like to be root bound, and you can keep them small easily in small pots, if you want to keep them small. They will grow as big as they have space for. All my passiflora died last year due to unexpectedly bad weather this last winter, but they grew easily in five gallon pots. I pinched back the new growth a lot to encourage branching, and used some lovely twisted branches to make a six foot trellis, and they thrived, but I did have to water them frequently. You might want to double the size of the pots that I used, but you can underplant them with something that doesn't need a lot of water.