I get very few naturally pollinated blooms on most of my vines and have to hand pollinate. I also keep some vines in the greenhouse year round so there's little chance of those flowers being pollinated by insects. With the vines that I keep outside during the summer maybe I just don't have the right pollinators being that I'm in zone 7? There has also been a dramatic decline in honeybee numbers and I'm sure that the number of other insect pollinators has also declined.

There are a few things to keep in mind here. For one, the bees may simply not have found the flowers yet. I have had some Passiflora for over a decade that just started to get approached by bees in the last couple of years. Also, there are many different species of bees,and Passiflora are usually only pollinated by the really large bumble or carpenter type in our yard. Lastly, hand pollinating will almost invariably allow more pollen to get accepted, giving you more seeds, thus more arils, which means more juice. That's enough of a reason to do it by hand!

Best luck,
Eric

Eric I wish the freaking carpenter bees would try pollinating some of my passies instead of drilling holes in the sauna!