Maypop (Passiflora incarnata) is usually grown from seed and will flower and set fruit the first year. This species is an annual that comes back from the roots in the spring. It has been my experience that a plant will only grow and flower in a pot for two years then it declines and doesn't come back the third or fourth year. In the ground it spreads by root suckers and will come up 10-30 feet away from the original plant, but not necessarily again where it was originally. I've tried replanting the roots from a pot in fresh soil and that really didn't work. So you should plant seeds every year to continue to have a robust flowering and fruiting plant. But note, that this species is not self fruitful, it needs another clone to set fruit (powered by bees or by you).

In this case I have them in the ground. Any idea why the one wouldn't be flowering? It's most vigorous in terms of growth otherwise.

It's hard to say why one plant will flower and the other won't, assuming they are getting the same care, fertilizer, etc. If the one without flowers did get more nitrogen than the one with flowers, that could be a factor. Otherwise, it may be necessary to stress the non-flowering plant by delaying watering. If water can't be controlled, then you may just have to be patient. In the wild P. incarnata probably doesn't get fertilized and watering can be sporatic. Controlled culture would be a change to the "normal" growing conditions for this species.

It's not really an annual (at least in it's native range), it's just deciduous and may (usually) does wander.

The maypop is not 'deciduous' (meaning it loses it's leaves seasonally) but rather an 'herbaceous perennial'. Herbaceous refers to the fact that it is a soft-tissued plant (non-woody such as true deciduous trees and shrubs), and perennial, of course to the fact that it persists for multiple growing seasons. In the temperate zone herbaceous perennials like maypop die back to the ground each winter, but in the tropics they typically don't. Banana is a good example of a giant tropical herbaceous perennial.

Sorry for the botany lesson, I just could not resist the temptation… :)

You are correct...I was hasty and trying not to get the original poster bogged down.

How's the fruit? My aunt LOVES passionfruit, she lives in Houston, she has Maypop wild around Houston, but she never saw flowers. I have possum purple

I've only had 3 small fruit so far. They seem pretty slow to ripen, and it's hard to tell when they're ready. It's looking like you need to wait until they fall off on their own.

But that's enough for a taste test, and it was pretty good! The taste is very hard to describe. "Grape" is the closest I can come up with, but there's a lot else going on there, so that doesn't do it justice.

There's not much pulp, but that's not a bad yield for a year-one perennial, and it also fills the niche of "pretty flower to grow up my mailbox," so I'm pleased overall.

My neighbor and I both had 4" plants. They grew very rapidly. Mine flowered about a month before his. Maypops need cross pollination. They are also invasive. Put them in a pot.

keep both, or no chance of fruit.