Ask Mr. Smarty Plants

There are several members of the Passiflora genus that are native to Texas: Passiflora affinis (bracted passionflower), Passiflora foetida (fetid passionflower) and Passiflora incarnata (purple passionflower). Most of them are native to South or South Central Texas. So, we chose the most glamorous one, Passiflora incarnata (purple passionflower) to use as an example. Since it is not native to North Central Texas, we are assuming that what you have is one purchased from a nursery. 

Our webpage on that plant says:  "To encourage bushiness, pinch the plants back during their first growing season." So, obviously, it won't hurt the plant to be pinched back, or flowers pinched off. Most flowering plants will be inspired to bloom again if the bloom is removed before the seed forms. The main purpose of a flowering plant is to make more plants just like it; in order to do this it has to set seed. If the flower is taken off before the plant does that, it will just go in and make more flowers. Now, there is a limit to that. Making flowers and seeds is a high-energy proposition for the plant, but if the plant is happy where you are growing it, it should do just fine. In fact, the first thing a passionflower does when it is planted is start putting out suckers. In Garland, where it is not native, it probably won't be so invasive, but in East Texas, they can simply take over. 

You might find this article interesting from Floridata, Passiflora incarnata.

Passiflora incarnata

Passiflora incarnata

Passiflora affinis

Passiflora foetida