Hi DrCindy. Im afraid I don't know about zones but I can quote John Vanderplanks book about the Star of Bristol and he was the breeder of this hybrid. Quote ' In 1984 I raised just over 300 seedlings of P'Amethyst' x caerulea, of which I named just three: 'Star of Bristol', Star of Clevedon and Star of Kingston, and exhibited these at the RHS in London. Since then I have sold many hundred young plants of these cultivars and to the best of our knowledge they are doing well in sheltered positions in the warmer southwest of England. Minimum temperature 32ºF (0ºC). These showy cultivars, with medium to large flowers of mauve, white and blue, make good conservatory or house plants, and can be grown outdoors in sheltered locations near dwellings in temperate climates similar to htat of the SW of England, where only mild frosts are experienced in normal winters. In warmer climates they will grow to about 4 metres (13 feet) and add charm and colour to any garden. They are well suited to the Mediterranean regions and southern states of the US. All three have retained the herbaceous characteristic of their parents and our original plants produce numerous new sucker growths from wide-spreading fleshy roots.' Hope this helps. Vanderplanks book was published in 1991 so there may well be more recent information elsewhere.

Are either of these edible? I have both and have not been able to obtain too many solid answers. I know I have posted this question before about other varieties but that is why I signed up here!
Thanks,
Jill

Hi DrCindy
See hardiness figures at link below. Nothing with 'Amethyst' or caerulea as a parent will be very palatable.
Myles

Here is a link that might be useful: Passiflora 'Star of Bristol'