I took in the Blue Passionflower and Maypop in the past few days (its like 11F-15F past week), was pretty surprised the Blue passionflower still had its leaves green, strongly attached, and not withered on the plant. Seems to be more cold hardy than the Maypop for me. Thought Passionflower would have "top growth is killed back by frost, but your Passion Flower will pop back to life in the Spring."... Well we've had a few 25F days before this week and its still loling alive... Mind you its not mulched, and all 5 Blue plants shared a 2gallon pot. So i assume the pot is pretty cold/frozen, yet this thing is still kickin' lol? The Maypop had all its leaves turn yellow and fall off months ago and the vine looks more yellow than green.

You've got two good plants there but there are alot more out there, equally as hardy as the Blue Crown aka Caerulea. You will also not there are some real pretty hybrids just as hardy.

You can find tons of information here;

http://passionflow.co.uk/passiflora-passion-flower-id-identification.h tm

Darren

PS Can I grow Passiflora indoors by a window? will it still pollinate the flowers and form fruit?

You can grow these plants indoors. I've had a bunch of cuttings growing under lights in my garage. Some of the plant are slower growers and make better indoor plants. I can't speak about these two because I haven't grown them.
They won't bear fruit tho, unless pollinated by hand or little flyin critters. I believe the blue crown will pollinate the maypop but I'm not sure if it works the other way. They will flower indoors without help. Perhaps one of the veterans here will chime in.