Scientific Name: Passiflora incarnata
Common Name(s): Passionflower Vine, Purple Passionflower, maypop, wild apricot

Photos by Kayla Sayre, Bella Vista POA Fisheries & Water Quality Sr. Technician
A) Passionflower bloom with symbiotic ants where flower connects to vine.
B) Palmate leaf with three deep lobes.
C) Passionflower once cross pollination has occurred but before fruit formation.
D) Passionflower fruit, also known as a maypop fruit.
E) Seeds contained within maypop fruit. Top shows seeds within pulp purse and bottom shows seeds outside of the purse.

Identification:

Passionflower vines have unique purple flowers and produce fruit called maypop. Passionflowers bloom from July to early September, but most commonly bloom in July in Bella Vista. Passionflowers have radial (circular) symmetry with three overlapping reproductive structures. At the base of the flower petals are arranged in whorls of five around the stem. There can be multiple whorls. Petals are bluish-white to purple. Overlaying the petals is a fringed white-and-purple corona, which is a cluster of hair-like appendages. The corona is patterned in a target design to entice pollinators to the middle of the flower, where the pollen is produced by the five anthers that lie above the corona. The anthers drop the pollen downward over the middle portion of the flower. Above the anthers are the three stigmas at the very top of the flower, which are often green but sometimes with purple splotching.

Between the anthers and the stigmas is an oval bulge called the ovary, where the maypop or fruit develops once fertilized. Once cross-pollinated, the three stamens fall and contact the pollen on the anthers, which fertilize the ovary. Passiflora incarnata are self-infertile, meaning they cannot produce fruit from their own pollen, so they require cross-pollination from bees to produce fruit. Bees leave traces of pollen on the anthers that are from other plants. Once fertilized, the flower closes, allowing the ovary to develop into fruit. The maypop fruit is named after the popping sound they make when stepped on. They are edible and develop in the late summer to early fall. They are about the size and color of a lime when mature. The thickness of the internal fruit varies depending on the abundance of water. Each seed is dark brown to black, with small pin-sized indentations throughout, and is encapsulated with other seeds in a small white purse that contains a juicy pulp. This pulp improves germination once outside the fruit.

Passionflowers grow on vines that contains specialized curling tendrils for attachment to sturdy structures such as trees, shrubs, or fences. The stems of the vines are smooth. The leaves are palmate, with three (and sometimes five) deep lobes reminiscent of theropod dinosaur or bird tracks. The leaf surface is smooth with margins finely toothed. Leaves are 6 to 15 centimeters in length.

https://plants.usda.gov/home

Range:

Passiflora incarnata is found in the continental United States in states east of the Rocky Mountains, and south of the great lakes.

Ecology:

Passionflower vines have evolved in ways that favor larger bees, such as carpenter bees and bumblebees, for pollination. The purple coloration attracts carpenter bees and bumblebees since bees prefer plants in the blue and purple wavelengths. The corona is patterned in a target design to entice pollinators to the center of the flower, where the pollen is produced by the five anthers that lie atop the corona. The space between the nectar and anthers is larger, so only larger bees can pick up and deposit pollen when drinking nectar. Carpenter bees and bumblebees become slightly intoxicated by the nectar as they drink and hang out on the plant for longer periods. This allows more pollen to collect on their back or for pollen from a different plant to be dislodged to allow for cross-pollination.

The leaves have two glands at the base that produce sweet nectar, which small ants feed on in exchange for protecting the leaves and flowers from insects, with two exceptions. Look closely at the above at photo (A) to see small ants along the stem. Specifically, the ants will swarm and sting insects that try to eat the plant. However, Gulf fritillary and variegated fritillary caterpillars have a resistance to the toxic chemical produced by the ants. They eat the leaves of passionflowers and lay their eggs on the flower. However, these caterpillars also protect themselves and the passionflowers by deterring mammals and birds with their vibrant orange color and black spikes. These bright colors signal to predators that they are poisonous when eaten, deterring them. The gulf and variegated caterpillars are solely dependent on passionflowers to survive in the same way that monarchs are dependent on milkweeds.

Passionflower has had interesting historic herbal uses by Native Americans and peoples of India. The maypop fruit contains compounds that may increase GABA, a neurotransmitter, production in the brain. Passionflower fruit was used by Native Americans to treat epilepsy in older people and to treat nerve pain. Additionally, it has been used in India to treat opioid addiction. It is also used to treat insomnia and anxiety since increasing GABA in the brain can be naturally sedating.

Cultivation:

Here in Bella Vista, passionflower is found in open areas with full sun. It can be found on the dry side of most of the dams but has been specifically spotted at Lakes Windsor and Avalon Dams.
Passionflower vines are in the family Passifloraceae, which includes 750 species across 27 genera that share the distinctive passionflower and fruit. Passionflower vines are perennials, meaning they come back each season. They can grow back from root shoots from the original plant as well as from seeds. The seeds germinate in the spring and do not require winter stratification. In warmer southern states with mild winters, they can grow continuously but die out in areas where freezing occurs. They grow in full sun in sandy and clay loam soil and can tolerate drought. They can grow in open prairie habitats, on slopes, or in flat areas. They do well in erosion-prone areas because, once established, they tend to dominate the landscape.