In my wanderings I came upon this. Since these fruits are so prolific that they are actually considered weeds, I did not realize that they could be a bit fussy about pollination. It sounds like when the vine blooms it would be best to hand pollinate to make sure you get fruit.
Adaptation: The purple passion fruit is subtropical and prefers a frost-free climate. However, there are cultivars that can take temperatures into the upper 20's (Â°F) without serious damage. The plant is widely grown in California as far north as San Jose, the Monterey Bay Area and the San Franciso Bay Area. The vines may lose some of their leaves in cool winters. The roots often resprout even if the top is killed. The plant does not grow well in intense summer heat. The yellow passion fruit is tropical or near-tropical and is much more intolerant of frost. Both forms need protection from the wind. Generally, annual rainfall should be at least 35 inches. Passion fruit vines make good container specimens but require maintenance. They perform well indoors.
Flowers: A single, fragrant flower, 2 to 3 inches wide, is born at each node on the new growth. The bloom, clasped by 3 large, green, lifelike bracts, consists of 5 greenish-white sepals, 5 white petals and a fringe like corona of straight, white-tipped rays, rich purple at the base. It also has 5 stamens with large anthers, the ovary and triple-branched style forming a prominent central structure. Purple passion fruit is self-fruitful, but pollination is best under humid conditions. The flowers of the yellow form are perfect but self-sterile. Carpenter bees are the most efficient pollinator, much more so than honey bees. Wind is ineffective because of the heaviness and stickiness of the pollen. The flowers can also be hand pollinated.