Genus
Passiflora
The Passiflora genus in the Plotwright catalog — 3 species: Blue passionflower, Maypop (purple passionflower), Passion fruit. Open any for hardiness, native range, wildlife value, and growing guidance.
Passiflora caerulea
Blue passionflower
A vigorous, semi-evergreen climbing vine from subtropical southern South America, grown for its intricate, unmistakable flowers — white-to-pale-blue petals beneath a crown of blue-and-purple-banded filaments. POWO (Kew) and Flora e Funga do Brasil record it as native to southern Brazil, Argentina, Uruguay and Paraguay. It is by far the hardiest commonly-grown passionflower, root-hardy to roughly zone 6b/7 and resprouting after a freeze, and it climbs fast by tendrils to clothe a fence, arch or trellis. The egg-shaped orange fruit that follows is edible but bland and insipid — it is NOT the commercial passion fruit — and the leaves and unripe fruit contain cyanogenic compounds, so only the ripe pulp is safe to eat. Its vigour is a warning as much as a virtue: in mild climates it suckers and self-seeds and can become weedy or invasive, so give it room and curb it.
Passiflora incarnata
Maypop (purple passionflower)
A fast-growing, tendril-climbing native vine of the eastern United States, named "maypop" for the fleshy egg-shaped fruits that pop underfoot. Its intricate 2.5-inch fringed flowers — white-to-lavender petals beneath a pinkish-purple filament crown and a raised central androgynophore — are precisely engineered for large carpenter bees. Woody in warm-winter climates and herbaceous (dying to the ground) where winters are cold, it climbs to 6-8 feet on a trellis and produces edible yellowish maypops in fall.
Passiflora edulis
Passion fruit
A vigorous, evergreen, tendril-climbing vine from the subtropics of southern Brazil, Paraguay, and northern Argentina, grown both for its strikingly intricate purple-and-white flowers and for its edible passion fruit. The flower is a small work of engineering: a ring of white-and-purple petals beneath a fringed corona of wavy purple-banded filaments, with the five anthers and three stigmas held on a raised central column at exactly the height a large carpenter bee brushes as it forages. Where winters are frost-free (USDA zones 9b-11b) it is a fast, hard-climbing perennial that can blanket a sturdy trellis or fence in a single season and produces round, leathery purple or yellow fruits whose aromatic, seedy pulp is the fragrant passion fruit of juices and desserts. Two honest cautions matter: it is a frost-tender plant grown as an annual or under glass where colder, and the unripe fruit and the foliage contain cyanogenic compounds and are mildly toxic, so only fully ripe fruit should be eaten.