// SPECIES PROFILE · VINE · NATIVE · HOST PLANT

Maypop / Passionflower

Passiflora incarnata

The cold-hardiest member of an otherwise tropical genus, Passiflora incarnata is the wild passionvine of the southeastern US, reaching its western limit in the Cross Timbers and Ouachita foothills of NE Oklahoma. Its three-inch fringed purple-and-white coronas look engineered rather than grown, and its egg-sized green fruits — the maypops — pop loudly underfoot when ripe. It is the sole or primary larval host for the gulf fritillary, the variegated fritillary, and (south of us) the zebra longwing, which is reason enough to grow it.

// QUICK FACTS

Family: Passifloraceae
Group: Herbaceous perennial vine
Native range: SE & S-Cent. US — PA south to FL, west to E TX/OK/KS
USDA hardiness: Zones 5–9 (Tulsa = 7a/7b — reliably root-hardy)
Mature size: 6–15 ft of new growth per year · spreads via root suckers
Sun: Full sun preferred — tolerates light afternoon shade
Soil: Sandy loam to clay; pH 6.1–7.5; well-drained
Water: Drought-tolerant once established — deep taproot
Bloom time: June–September in NE Oklahoma
Fruit ripe: August–October — rind wrinkles & yellows when ripe
Larval host: Gulf fritillary, variegated fritillary, zebra longwing
Pollinators: Carpenter bees (Xylocopa virginica) — primary; bumblebees secondary
Wildlife value: Butterfly host · pollinator nectar · wildlife & human food
Ecological role: Native vine · butterfly host · edible fruit · pollinator beacon

Maypop / Passionflower (Passiflora incarnata) — purple-and-white fringed corona — *Passiflora incarnata* — the unmistakable fringed corona of filaments above five sepals and five petals, with the pollen- and stigma-bearing column raised on a central stalk. Photo via Wikipedia / Wikimedia Commons.

Identification

[ field key — flower · leaf · tendril · fruit ]

Flower — the giveaway

Solitary, axillary, 2.5–3 in across, with five pale-lavender sepals and five matching petals (look identical) surmounted by a fringed corona of filaments banded purple, white, and pink. From the center rises a stalked column (androgynophore) bearing five anthers and three downward-curving stigmas — a structure found nowhere else in our flora. Bloom is open only one day; carpenter bees trip the anthers and dust their backs with pollen as they shoulder under the corona for nectar at the base.

Leaves & tendrils

Alternate, deeply three-lobed (rarely 5-lobed), 3–6 in across, with finely-toothed margins and a pair of small extrafloral nectaries on the petiole near the leaf base — these reward ants that drive off egg-laying butterflies. From the leaf axil emerges a single coiling, unbranched tendril that grasps any wire, twig, or fellow stem within reach. Crushed foliage has a faint sour smell.

Fruit — the maypop

Egg-shaped berry 1.5–2.5 in long, smooth and dull green ripening to yellow-green and slightly wrinkled. Inside is a hollow cavity full of seeds each surrounded by a translucent aril of yellow-orange pulp — the edible part, with a flavor between guava, apricot, and lemonade. Unripe fruit is starchy and astringent; ripe fruit falls free or detaches at a touch. The "pop" of an underripe maypop trodden on a path is the source of the common name.

Confusables

The only other passionvine likely to occur with us is the yellow passionflower (Passiflora lutea), a delicate, much smaller woodland species with shallowly 3-lobed leaves, dime-sized greenish-yellow flowers, and small dark-purple fruits — a different beast entirely. Garden passionvines (P. caerulea, P. edulis) are not cold-hardy in Tulsa without protection. Our wild plant is sometimes misidentified as a cucurbit at first glance — both have lobed leaves and tendrils — but the fringed corona ends the question.

Habitat & Range in NE Oklahoma

Passiflora incarnata is at its northwestern edge in NE Oklahoma. It is common along fence lines, road shoulders, sandy field margins, and open woodland edges throughout the eastern third of the state, especially in Cherokee, Adair, Sequoyah, Muskogee, Wagoner, and Creek counties, and reaches west into Tulsa, Osage, and Pawnee on appropriate substrates. It favors deep sandy or sandy-loam soils where the perennial root system can drive two to three feet down to escape both summer drought and winter cold.

The vine is a disturbance specialist: it colonizes brushy edges, old pastures, recently mown right-of-ways, and the post-fire gaps in Cross Timbers oak woodland. New stems emerge late — often not until mid-May, well after frost — and die back fully at the first hard freeze; only the fleshy underground rhizomes overwinter. In the Ouachita and Ozark foothills it climbs up to small openings in oak-hickory canopy; on the prairie margins it is typically found in linear, sun-baked strips along railbeds and fence corners.

Maypop tolerates the heavy red-clay subsoils common in the Tulsa basin provided drainage is good; in waterlogged ground it rots over winter. It is most luxuriant where deep sand or terrace alluvium of the Arkansas River, Verdigris, or Illinois rivers gives the rhizomes free root-run.

Ecology & Wildlife Value

[ butterflies · carpenter bees · ant guards · mammals ]

Fritillary host plant

Passionvines are the obligate larval host for the entire Heliconiinae subfamily of butterflies. In NE Oklahoma P. incarnata is the larval food of the gulf fritillary (Agraulis vanillae), the variegated fritillary (Euptoieta claudia), and rare strays of the zebra longwing (Heliconius charithonia). Larvae are bright orange with branching black spines and feed openly — their sequestered cyanogenic glycosides make them unpalatable to most birds.

Carpenter bee pollination

The flower's heavy pollen and unusual hinged anthers are calibrated for the eastern carpenter bee (Xylocopa virginica): the bee's broad thorax exactly fits under the corona, brushes the anthers while it nectars, and brushes the down-curved stigmas on the next visit. Bumblebees (Bombus pensylvanicus, B. impatiens), honeybees, and the occasional ruby-throated hummingbird also visit, but fruit set is sharply higher where carpenter bees are abundant.

Extrafloral nectaries & ants

The petiole nectaries are not for pollinators — they are ant feeders. Ants attracted to the sugar reward aggressively patrol the vine and remove butterfly eggs and small larvae. This is one of the textbook examples of indirect plant defense via third-party recruitment. Heliconiine butterflies have evolved a suite of counter-adaptations: laying eggs on tendril tips out of ant range, and laying single eggs rather than clusters.

Mammal & bird use

Ripe fruit is eaten by raccoons, opossums, gray foxes, white-tailed deer, and box turtles; passing through the gut scarifies the seed and is the primary natural dispersal route. Cardinals, mockingbirds, and catbirds occasionally peck open fallen fruits. Deer will browse young foliage in spring but generally leave established stands alone.

If you grow it for the butterflies, expect defoliation. Healthy host-plant management means accepting that gulf fritillary larvae will chew the vine bare in late summer. The rhizomes resprout the following spring with no harm done. Do not spray BT or any insecticide on a vine you grow as a host plant.

Horticulture & Care

[ siting · trellising · containment · propagation ]

When to plant intentionally

Plant container-grown maypop in April through early June, after the soil has warmed past 60°F. Bare-root rhizome divisions move best in early spring while the plant is still dormant. Do not plant in the fall in our zone — first-year roots do not have time to anchor before winter heave.

Planting & establishment

Sun: 6+ hours direct sun for best bloom and fruit set; light afternoon shade is acceptable in west-facing exposures.
Soil: any well-drained loam, sandy loam, or amended clay; pH 6.1–7.5. Tolerates lean soil but resents wet feet.
Hole: twice the width of the root ball, same depth; backfill with native soil — no need to amend.
Spacing: 6–10 ft between plants, or one per arbor. Each plant suckers; expect a 6-ft-wide colony within three years.
Water: water deeply weekly through the first summer; established plants need almost none.
Mulch: 2–3 in of shredded hardwood, leaving a clear ring at the crown.

Trellising & structure

Maypop reaches 6–15 ft of new top-growth each year and needs a sturdy, permanent support: a wood arbor, a chain-link panel, a sunny fence, or the woody framework of an established shrub such as Crataegus mollis or Sambucus canadensis. The tendrils grasp anything 1/4 inch or slimmer; thicker poles need initial twine training.

Maintenance & containment

Cut to the ground after the first hard freeze — the top dies anyway. Pull last year's tangle off the trellis in March before new shoots emerge.
Suckers: the rhizome wanders 3–10 ft per year. In a managed bed, install an 18-in vertical root barrier or sever runners with a sharp spade each spring.
Fertilizer: none needed; over-rich soil produces foliage at the expense of bloom.
Pruning: in summer, pinch terminal shoots to encourage branching and more flower buds.

Pests & diseases

Heliconiine larvae — "damage" you should welcome (see callout above).
Cucumber beetles & flea beetles chew small holes in young leaves but rarely cause real damage.
Fusarium wilt appears occasionally in poorly drained sites; rotate or replant in fresh ground.
Root rot in waterlogged winter soils — the single biggest killer of garden plants. Ensure drainage.

Propagation

Easiest by rhizome division in early spring — lift a sucker with attached roots and move it. Stem cuttings root in moist sand under mist in summer. Seed germinates erratically over a year or more and benefits from acid scarification or passage through a deer.

Cultivars & selections

Most landscape plantings use the wild type; named selections are uncommon and primarily ornamental.

Selection	Origin	Distinguishing feature	Notes for Tulsa
Wild type	local seed/divisions	standard purple-white corona, full vigor	most reliable; locally adapted; first choice
'Incense'	USDA hybrid (P. incarnata × P. cincinnata)	larger 5-in fragrant violet flowers, frilled corona	marginally hardy in 7a; mulch crown heavily; treat as die-back perennial
'Alba'	nursery selection	pure-white sepals/petals, white-pink corona	uncommon but sound; same hardiness as wild type
'Cocky's Brew'	cultivar selection	heavier fruit set, slightly larger maypops	worth trialing if fruit production is the goal

Cultural & Material Uses

Few American natives carry as much layered meaning as the passionflower — its name comes from 17th-century Spanish missionaries in South America who read the flower's structure as an emblem of the Passion of Christ (the corona for the crown of thorns, the five anthers for the wounds, the three stigmas for the nails). The plant has a continuous documented use in eastern North America from pre-Columbian times to the modern herbal trade.

Edible fruit: ripe maypops — yellow, slightly wrinkled, falling to the ground — are eaten raw by sucking the seed-aril mass from the hollow rind, or strained into juice, jelly, syrup, or sorbet. Flavor is tart-sweet, between guava and apricot. Unripe fruit is starchy and mildly cyanogenic; do not eat green.
Indigenous food & medicine: the Cherokee, Houma, and other southeastern nations ate the fruit and prepared infusions of the leaves and roots as a sedative, sleep aid, and topical poultice. The plant was widely cultivated around villages in the Southeast at European contact.
Herbal sedative: dried aerial parts of P. incarnata are an officially recognized herbal medicine in the German Commission E monographs and the European Pharmacopoeia, used for anxiety and mild insomnia. The active constituents are a mix of flavonoids (vitexin, isovitexin) and indole alkaloids.
Pollinator garden anchor: a single mature vine on a south-facing fence will support carpenter bees from June bloom through the fritillary migration in September.
State wildflower of Tennessee — recognized 1919.
Modern horticulture: the genus Passiflora contains roughly 550 species; P. incarnata is the cold-hardy parent of many tropical-hybrid garden vines including 'Incense' (USDA-bred for SE gardens).

Sources & Further Reading

USDA NRCS PLANTS Database — Passiflora incarnata: plants.usda.gov/plant-profile/PAIN6
USDA NRCS Plant Guide — Passiflora incarnata (PDF), Plant Materials Program.
Lady Bird Johnson Wildflower Center — Passiflora incarnata: wildflower.org — PAIN6
Missouri Botanical Garden Plant Finder — Passiflora incarnata.
Oklahoma Biological Survey — Atlas of the Flora of Oklahoma, county-level distribution maps.
Oklahoma State University Extension — native vines and pollinator plantings for Oklahoma landscapes.
Smiley, J. (1978), "Plant Chemistry and the Evolution of Host Specificity: New Evidence from Heliconius and Passiflora", Science 201: 745–747.
Miroddi, M. et al. (2013), "Passiflora incarnata L.: Ethnopharmacology, clinical application, safety and evaluation of clinical trials", Journal of Ethnopharmacology 150(3): 791–804.
European Medicines Agency, Committee on Herbal Medicinal Products — Assessment report on Passiflora incarnata L., herba.
Wikipedia — Passiflora incarnata: en.wikipedia.org/wiki/Passiflora_incarnata (CC BY-SA 4.0).

Maypop / Passionflower

Identification

Flower — the giveaway

Leaves & tendrils

Fruit — the maypop

Confusables

Habitat & Range in NE Oklahoma

Ecology & Wildlife Value

Fritillary host plant

Carpenter bee pollination

Extrafloral nectaries & ants

Mammal & bird use

Horticulture & Care

When to plant intentionally

Planting & establishment

Trellising & structure

Maintenance & containment

Pests & diseases

Propagation

Cultivars & selections

Cultural & Material Uses

Sources & Further Reading

Companion Planting