What is passionflower? A plain guide

Passionflower usually means Passiflora incarnata, a climbing perennial vine native to the southeastern United States, sold as dried herb for tea, as a liquid extract or tincture, or in capsules. The name comes from 16th-century missionaries, who read the flower's unusual parts as symbols of the crucifixion — not from any calming or "passionate" effect.

Which species, and which part is used

The genus Passiflora has more than 500 species, and three matter for anyone reading a label:

• Passiflora incarnata (purple passionflower, maypop) — the species behind essentially all human research and regulatory guidance on passionflower as a supplement, including the European Medicines Agency's herbal monograph. Its dried leaves, stems and flowers (the aerial parts) are what's used.
• Passiflora caerulea (blue passionflower) — a different, widely cultivated ornamental species that also turns up in some herbal extracts and blends. It hasn't been studied in human trials the way P. incarnata has, so research on one doesn't automatically apply to the other.
• Passiflora edulis (passion fruit) — grown for its edible fruit, not its leaves. This is a food crop, not the plant behind the tea or extract most "passionflower" supplement products use.

If a product just says "passionflower" without naming a species, there's no way to know which one you're getting — see how to choose a good passionflower.

Where the name comes from

Spanish missionaries in 16th- and 17th-century South America described the flower's structure as a teaching tool for the Passion of Christ: the fringed corona read as the crown of thorns, the five petals and five sepals as ten of the apostles, the three stigmas as the nails, and the tendrils as the whips of the flagellation. That symbolism, first published by the Italian friar Giacomo Bosio in 1609, is where "passionflower" and the genus name Passiflora both come from — nothing to do with romance, and nothing to do with a calming effect.

How it's sold

Passionflower is sold as cut, dried herb for tea, as a liquid extract or tincture at various concentrations, and as a powdered or dried extract in capsules — the European Medicines Agency's herbal monograph lists all of these as recognized preparations of P. incarnata. A 2004 review of the genus found P. incarnata has documented central-nervous-system-depressant properties in laboratory and animal research, and identified flavonoids as the plant's major active compounds — the exact mechanism in people isn't confirmed.

Passionflower and pets

Some calming products marketed for dogs and cats list passionflower as an ingredient, but there's no published veterinary dosing research behind it. Whether, and how much, to give an animal is a question for a veterinarian, not something this page — written about the human supplement — can answer.

Questions people ask

Is passionflower a perennial?

Yes. Passiflora incarnata is a perennial vine — it dies back to the root in colder winters and regrows the following spring, generally hardy in USDA zones 6-9.

Where does passionflower grow?

Passiflora incarnata is native to the southeastern United States, from Texas and Florida north into Virginia and parts of the Midwest, and grows wild along fence lines, roadsides and disturbed ground.

What does passionflower tea taste like?

Most people describe it as mildly grassy and slightly floral, closer to green tea than to a fruity herbal blend — which is why it's commonly sold pre-mixed with chamomile or lemon balm.

Is passionflower fruit edible?

Passiflora incarnata's fruit, called a maypop, is edible once fully ripe, though tart. It's a different fruit from commercial passion fruit, which comes from the separate species Passiflora edulis.

Can you smoke passionflower?

Dried passionflower leaf has a history of being smoked in some folk traditions, but no clinical research has tested smoking it for safety or effect. Inhaling any combustion byproducts carries its own risks separate from tea or a capsule, and nothing here recommends it.

How do you make a passionflower tincture?

A tincture is made by macerating the dried herb in alcohol; the European Medicines Agency's monograph lists several ratios used in registered products, from roughly 1 part herb to 1 part solvent up to 1:8. Getting the ratio and solvent strength right is a formulation question — how to choose a good passionflower covers what to look for when buying one rather than making it.

How do you grow passionflower?

That's a gardening question this page doesn't cover in detail — P. incarnata is typically started from seed, root cuttings or a nursery plant, prefers full sun, and spreads readily once established. A gardening or extension-service guide is a better source for planting depth, spacing and care than a supplement page.

Related reading: passionflower benefits: what the research does and doesn't show, how much passionflower should you take a day?, and how to choose a good passionflower.