There are now in excess of 550 species and over 700 cultivars, but not all are found in commercial production.
Tender passion flower vines are far more numerous than hardy passion flowers and contrary to what many adverts would lead you to believe there are no truly hardy red passion flowers.
A Good example of a hardy passion flower is Passiflora caerulea which is a species cultivated worldwide and performs well in British gardens. There are now many cultivars suitable for growing outdoors, P. ‘Constance Elliot’, ‘Lynda Joy’ and P. Damsels Delight (P. ‘Silly Cow’) to name just a few.
Examples of half hardy passion flowers are P ‘Amethyst’ and P.x violacia ‘Victoria’
A large proportion of the passion flowers need varying degrees of heat on them during the winter and so are more suitable for conservatories or greenhouses.
Passiflora vitifolia ‘Scarlet Flame’ is a good example of a red vine, Passiflora alata is an excellent plant for scent and Passiflora citrina produces an abundance of bright yellow flowers for much of the year.
Passion flowers when grown in their natural habitat are often found in poor, well-drained soils, so care must be taken not to over water or over pot.