“Dragon fruit” (Pitahaya), are sweet, crunchy fruits about the size of a fist. On the outside, they look like oval balls of fire (thick red skin) decaled with green flames (leaves). On the inside, the majority of the fruit is either white or purple or yellow, and is peppered with what looks like black sesame. Most of the varieties taste similar. They grow from a specific night-blooming cacti (Hylocereus) whose flowers only bloom for a single night. And because of this, if the usual pollinators aren’t around, the cacti simply won’t produce any fruit. That’s when you have to take matters into your own hands.
I believe all dragon fruit flowers are hermaphrodites, and many of them are self-pollinating. So all you really have to do is take a fine brush (such as a makeup or paint brush) and collect pollen from the anthers to apply to the stigma, within the same flower if self-pollinating, or across flowers if not.
Harvest dragon fruits when the “flames” (leaves) just start to brown at the tips or slightly before. The fruit pictured below was harvested a little too early 😛
Here are some photos from my backyard August 2016:
More info:
http://tastylandscape.com/2013/07/30/how-to-get-dragon-fruit-cactus-to-fruit/