The passion flower gets its name from the Passion of Christ, not from any association with romantic love or emotional fervor. In the late 1500s and early 1600s, Spanish missionaries exploring Central and South America encountered these striking, structurally complex blooms and believed they saw symbols of the Crucifixion encoded in every part of the flower. The name stuck, eventually becoming the basis for the genus name Passiflora, which now includes over 500 species spread across the Americas and beyond.
What the Missionaries Saw in Each Part of the Flower
The symbolism the missionaries assigned was surprisingly detailed, covering nearly every visible structure of the flower. At the center, the three prominent stigmas represented the three nails used in the Crucifixion. Just below them, the five anthers stood for the five wounds Christ received. The ring of thin, thread-like filaments radiating outward from the center, known as the corona, was interpreted as the crown of thorns. The ten petal-like structures (technically five petals and five sepals, which look nearly identical in most species) represented ten of the twelve apostles, with Judas and Peter excluded for their betrayal and denial. The vine’s coiling tendrils evoked the whips used during the scourging, and the plant’s pointed leaves were said to resemble the lance that pierced Christ’s side.
Not every missionary agreed on every correspondence. Some accounts assigned different meanings to the tendrils or leaves, and a few early descriptions added the round fruit as a symbol of the world Christ came to save. But the broad framework was consistent enough that it spread rapidly through Catholic Europe as a devotional curiosity. The flower became a minor sensation among theologians and naturalists who saw it as evidence of divine design embedded in the natural world.
How the Name Reached Europe
The story of how the name was popularized in Europe centers on a handful of key figures. Spanish missionaries in Mexico and Peru had been calling the plant “la flor de las cinco llagas” (the flower of the five wounds) and similar names for decades before formal descriptions reached European scholars. Around 1609 to 1610, the Italian historian and ecclesiastical scholar Giacomo Bosio published an account of the flower based on drawings and descriptions brought to Rome by Augustinian friars, particularly Emmanuel de Villegas, who had seen the plant firsthand in the New World. Bosio’s description, which appeared in a treatise on the Holy Cross, gave educated Europeans their first detailed look at the flower and its supposed religious symbolism.
The name “Passiflora” was later formalized by Carl Linnaeus in 1753 when he classified the genus in his Species Plantarum. Linnaeus drew on the existing tradition of calling it the passion flower, translating the common name directly into botanical Latin: passio (suffering) and flora (flower). By then the plant had been cultivated in European gardens for over a century, and the religious name was too deeply entrenched to displace. Even as botany moved away from theological readings of nature, the name remained.
What the Flower Actually Looks Like Up Close
Passion flowers are genuinely unusual in the plant world. The structures the missionaries found so evocative are not just visually striking but functionally complex. The corona filaments, which form that dramatic radiating ring, are outgrowths from a cup-shaped structure called the hypanthium. In Passiflora incarnata, one of the most common North American species, these filaments produce scent and serve as both a visual lure and a landing platform for pollinators. The flowers are typically five to seven centimeters across and bear multiple series of these filaments, giving them their distinctive fringed appearance.
Rising from the center of the flower is a column called the androgynophore, which elevates both the male and female reproductive parts above the petals. The five anthers dangle from this column on flexible stalks, and above them sit the three stigmas, each curving outward. This elevated, almost architectural arrangement is part of what makes passion flowers so visually complex compared to simpler blooms. Carpenter bees, one of the flower’s main pollinators, land on the corona filaments and walk in a circle under the anthers while probing for nectar, essentially being dusted with pollen as they feed.
The Pollination Dance
The mechanics of how passion flowers get pollinated are unusually precise. In Passiflora incarnata, carpenter bees arrive, land on the corona, and face inward toward the central column while circling it. To reach the nectar at the base of the chamber, they have to grip the filaments with their legs and pull themselves downward, which brings their bodies into contact with the pollen-bearing anthers overhead.1Flora. New insights into floral morph variation in Passiflora incarnata L. (Passifloraceae) in Tennessee, U.S.A. This is not a casual brush-and-go arrangement. The flower essentially requires a pollinator of a certain size and strength, which is why large bees tend to be the most effective visitors.
In other species the details shift. Research on Passiflora foetida found that carpenter bees and the giant honey bee were both frequent visitors, but successful fertilization depended heavily on the position of the flower’s styles. Only flowers whose styles had curved fully downward could self-pollinate on their own, providing a backup when pollinators were scarce.2Journal of Plant Research. Stylar curvature and its influence on the reproductive assurance in Passiflora foetida This kind of built-in insurance policy makes sense for a genus that spans such diverse habitats, from dense tropical forests where pollinators are plentiful to disturbed roadside areas where visits can be unpredictable.
A Very Old and Very Diverse Genus
The genus Passiflora is ancient. Molecular studies estimate that the major subgroups within the genus began diverging roughly 33 to 38 million years ago, during the late Eocene. The ancestors of modern passion flowers appear to have arrived in Central America and diversified rapidly from there, with many long-distance dispersal events spreading the genus across the Americas and eventually to parts of Asia, Australia, and the Pacific islands.3PubMed Central. Phylogeny, biogeography and divergence times in Passiflora (Passifloraceae)
Today the genus includes over 500 recognized species, making it one of the most species-rich genera of flowering plants. These range from massive woody vines that climb forest canopies to small herbaceous creepers. Some produce edible fruit, others are purely ornamental, and a handful are weedy colonizers of disturbed land. The diversity is staggering for a single genus, and it has made Passiflora a favorite subject for evolutionary biologists studying how plant lineages diversify over time.
An Evolutionary Arms Race with Butterflies
One of the reasons passion flowers are so diverse has to do with an ancient ecological conflict. Heliconiine butterflies, the colorful longwings common across the American tropics, lay their eggs almost exclusively on Passiflora plants. Their caterpillars feed on the leaves, and this relentless herbivory has driven the plants to evolve an impressive arsenal of defenses. The genus produces a wide variety of cyanogenic glucosides, compounds that release hydrogen cyanide when chewed, making the leaves toxic to most insects. Leaf shape within the genus is wildly variable, likely as a form of visual camouflage that makes it harder for egg-laying butterflies to recognize the plant. Perhaps most remarkably, some species produce small yellow bumps on their leaves or tendrils that mimic heliconiine eggs, discouraging female butterflies from laying real eggs nearby since caterpillars are cannibalistic and a mother butterfly avoids spots that look already occupied.4PubMed. The arms race between heliconiine butterflies and Passiflora plants – new insights on an ancient subject
The butterflies, in turn, have evolved their own countermeasures, including the ability to detoxify some of the plant’s poisons and to distinguish real eggs from fake ones. This back-and-forth escalation is one of the classic examples of coevolution in biology, first highlighted by researchers in the 1970s and still actively studied. The sheer variety of passion flower species may itself be a product of this arms race, with different lineages evolving different defensive strategies against different butterfly populations.
Passion Fruit and Its Connection to the Flower
If you have eaten passion fruit, you have eaten the product of a passion flower. The commercially grown passion fruit sold in supermarkets comes primarily from Passiflora edulis, a South American species whose common name is simply a direct inheritance of the religious label the missionaries gave to the genus. The purple and yellow varieties of commercial passion fruit are both forms of this species. Several other Passiflora species produce edible fruit as well, including P. ligularis (sweet granadilla) and P. quadrangularis (giant granadilla), though these are less widely known outside tropical regions.
The fruit itself develops from the same elaborate flower. After pollination, the ovary at the center of the bloom swells into a round or oval fruit filled with seeds, each surrounded by a gelatinous, intensely flavored pulp. The connection between the ornamental passion flower people grow on trellises and the tropical fruit they buy at the store is not always obvious, partly because the most common ornamental species in temperate gardens, like P. incarnata and P. caerulea, produce fruit that is edible but bland compared to the cultivated varieties.
The Calming Herb Named for Suffering
There is a certain irony in the fact that a plant named for the suffering and death of Christ has become best known in herbal medicine as a calming agent. Passiflora incarnata, the species most commonly used medicinally, has a long history of use for anxiety, insomnia, and nervous restlessness. It appears in pharmacopeias in Europe and the Americas and is sold as a dietary supplement in teas, capsules, and tinctures.
The science behind these calming effects is still being worked out, but the leading explanation involves the brain’s GABA system, which is the same system targeted by prescription anti-anxiety drugs like benzodiazepines. A systematic review of P. incarnata research found evidence that the plant’s compounds interact with both GABA-A and GABA-B receptors and may also influence how the brain recycles GABA, though the exact mechanism remains unclear.5PubMed Central. Passiflora incarnata in Neuropsychiatric Disorders—A Systematic Review The research is promising enough that P. incarnata is taken seriously in clinical settings, but it is not without risk. At least one reported case involved a woman who developed heart rhythm abnormalities after taking a passion flower supplement at standard doses, a reminder that “herbal” does not automatically mean “harmless.”6Clinical Toxicology. Toxicity of Passiflora incarnata L.
Why the Misconception About Romantic Passion Persists
Given how the word “passion” is used in everyday English, it is entirely natural to assume the flower was named for intense emotion, desire, or romantic feeling. The word has drifted far from its Latin root over the centuries. In Latin, passio meant “suffering” or “enduring,” and in early Christian usage it referred specifically to the suffering of Christ during the events leading to the Crucifixion. That theological meaning was the only one the missionaries had in mind. The broader sense of “passion” as strong emotion or enthusiasm developed later in English, gradually overtaking the religious meaning in everyday speech.
This etymological gap creates a persistent misunderstanding. People who grow passion flowers, eat passion fruit, or drink passion flower tea often assume the name has something to do with love or desire, and marketing for passion fruit products sometimes leans into this association deliberately. It is one of those cases where a word’s history and its current meaning have almost completely parted ways, and the flower’s name preserves a meaning that most English speakers no longer encounter outside a church.
Passion Flowers in Ornamental Gardening
Beyond their religious, medicinal, and ecological significance, passion flowers have been popular ornamental plants since they first arrived in European gardens in the early 1600s. Their complex, visually arresting flowers make them favorites for trellises, arbors, and conservatories. Passiflora caerulea, the blue passion flower, is the hardiest species commonly grown in temperate climates and can survive mild winters outdoors in parts of Europe and the southern United States. In warmer regions, dozens of species and hundreds of hybrids are cultivated, bred for flower color, size, fragrance, and cold tolerance.
The plants are vigorous growers, and some species can become invasive outside their native range. P. incarnata, for example, spreads aggressively by underground runners in the southeastern United States, popping up in garden beds, fields, and along roadsides. Gardeners who plant passion flowers for their beauty sometimes find themselves managing an enthusiastic colonizer. The flip side of that vigor is resilience: passion flowers are generally tough plants that tolerate poor soil, heat, and drought once established, which helps explain why the genus has been so successful across such a wide range of habitats over the past 30-plus million years.
For anyone growing passion flowers at home, the most common disappointment is a vine that produces abundant foliage but few flowers. This usually comes down to too much nitrogen fertilizer, which pushes leaf growth at the expense of blooming, or too little direct sunlight. The plants flower on new growth, so hard pruning in late winter or early spring encourages the kind of fresh shoots that produce the elaborate blooms the missionaries found so captivating four centuries ago.