Is passiflora native? They might just be struggling ornamentals that escaped someone's trellis.
Is there a 'wild' variety? Like strawberries, California poppies etc that have smaller, less appealing varieties that grow without being cultivated? If so then the alkaloid profile may be completely different from the common variety.
They are easy to grow if you want to use it. Pretty too.
Sine experientia nihil sufficienter sciri potest -Roger Bacon
*γνῶθι σεαυτόν*