Plant Profile: Passionflower
Foraging Stress Relief with Ecological Benefits
If anyone tries to tell you that native plants aren’t as beautiful as exotic ones, stop them immediately and show them passiflora incarnata. Its bizarre-looking flowers are uniquely different than most, with their alien-like, protruding pistil and stamen and crimped-hairlike filaments. What’s even more interesting is that they produce a fruit which tastes sour and sweet like a tropical fruit, yet they grow in all sorts of different climates across the eastern US.
My partner spent his childhood wandering around the Ozark woods, so he can often identify edible wild plants (even if the names he calls them are usually creative and not their actual name– see: “sour flower” and “sticker chip”). Passionflower was one of the first that I can remember learning from him. I couldn’t believe it was native to our area and I certainly couldn’t believe it produced a real passionfruit. But I watched as he plucked a fruit, cracked it open, and ate the seeds and pulp with great enjoyment. “That one wasn’t ripe enough, but it’s still good!” he claimed. In my opinion, unripe passion fruit leaves a lot to be desired, but the ripe ones are a real treat. The plant is sometimes referred to as “Maypop” due to it growing in the month of May and the “pop” sound its fruit makes when stepped on.
Varieties & Look-Alikes
The particular variety of passionflower that’s native here in the southeast part of the US is passiflora incarnata, but there are over four-hundred different varieties of passionflower. The fruit you probably imagine when you hear “passion fruit” comes from the variety passiflora edulis, which is less frost tolerant than p. incarnata and its fruit is substantially more sweet and flavorful. P. edulis thrives in hardiness zones 9-11 (subtropical to tropical) while p. Incarnata tolerates zones 5-10. P. incarnata does produce edible fruit with a tropical flavor, but it is a bit more sour and not quite as sweet. This variety is often grown for its flowers instead, which can be used as a powerful sedative and nerve tonic. Besides its medicinal uses, p. Incarnata is notable for its efficient groundcover and for the shelter and food it provides for wildlife.
Identifying Passiflora Incarnata
Stems & Leaves
Due in part to its degree of uniqueness, passiflora varieties are quite easy to identify, especially when flowering. Even its leaves are pretty easy to spot.
Passionflower grows long tendrils when the weather gets consistently warm, vining across the landscape. Its leaves are dark green and are arranged alternately on the vine. They have three distinct lobes, no hairs, and are not toothed. Though it grows in a long vine, it doesn’t require a trellis or another plant to climb for it to produce flowers and fruit. Other invasive vines like English ivy or wisteria can choke out other plants and destroy ecosystems over time, but passiflora dies back each year, and won’t compromise other native plants.
Flowers
The plant’s flowers are striking, and in my opinion, look a bit bizarre. At first glance, the flowers resemble a tropical flower, having ten white-lavender colored petals and scraggly-looking, bright, purple-pink filaments arranged around a central crown. The flower’s reproductive organ in the central crown protrudes out quite a bit and is white and bright green.
“Passiflora incarnata […] has extrafloral nectaries at the base of its leaves, which are button-like glands that produce nectar like a flower, but are not located in the flower. This allows the plant to make nectar all the time—not just when the plant is flowering.
This is important because ants are attracted to these nectaries, and will defend them—in turn, reducing damage that might be done to the leaves by other insects. So, while it's a different strategy than egg mimicry, the end result is similar: reducing damage to the plant's leaves and increasing its chances of survival.”
—Michaela DiGiovanni for Warnell School of Forestry and Natural Resources, U of Georgia
The scent of passiflora incarnata’s flower is surprisingly underwhelming compared to how it looks. It’s difficult to describe, but its scent is more salty than floral. When brewed as a tea, I recommend blending it with more fragrant herbs like mint, hibiscus, or lemon balm.
Fruit
Throughout summer, passionflower will produce passion fruit! Though not exactly the same as the tropical passiflora edulis, which is grown for its sweet and sour flavor in South America, the fruit of passiflora incarnata is a sweet and sour treat. When fully ripe, the fruit will often fall off the vine– that’s when it’s at its sweetest and most delicious.
Benefits for Wildlife & the Ecosystem
Passionflower has an amazing, mutually beneficial relationship with ants. The plant’s extrafloral nectaries, or glands that produce nectar that are located outside the flower, attract ants to its sugary goodness. In return, the ants protect the flower from harmful insects as they feed on the nectar, acting as tiny bodyguards for passiflora incarnata. Ants will even go so far as to “girdle” plants that attempt to out-compete passionflower, taking them down so that its host plant can survive.
Passion flower is a host plant for the Agraulis vanillae butterfly, also known as the passion butterfly, for obvious reasons. Afraulis vanillae is a fritillary butterfly, a distant cousin to monarchs who are sadly, like monarchs, endangered. These butterflies are excellent pollinators and are therefore an important part of the ecosystem. Insects like these work with native plants like passiflora incarnata to keep the ecosystem in balance. The plant provides a home and food for these insects to thrive, and the insects’ consumption of the plant helps keep its wandering vines in check.
In addition to becoming food for pollinators and other wildlife, passiflora incarnata won’t take over and damage an ecosystem (as invasive plants like wisteria and English ivy do) because it dies off each fall. It will return the next spring, ready to provide food and shelter for insects and provide groundcover for weed suppression (weeds meaning the more troublesome creatures like invasive grasses).
Benefits for People
Passiflora incarnata has been used as medicine for centuries across the world. It was historically used to treat respiratory ailments, anxiety, and insomnia. Today, its medicinal components are still used to alleviate the same ailments due to its sedative, antispasmodic, and anti-microbial properties. Its most commonly known use is treatment of insomnia and nervousness or anxiety. Its effects are more mild than other sedative herbs like valerian or kava, but it is still a potent relaxation herb, especially when combined with other mildly sedative herbs like lemon balm, chamomile, or lavender.
Its effects on the brain are believed to be caused by the chemical present in passiflora incarnata called gamma aminobutyric acid, which produces a sensation of calm in the body by lowering brain cell activity. In studies, passionflower has shown to be as effective as certain benzodiazepines such as oxazepam in treating generalized anxiety disorder and insomnia. This herb has also shown promising signs of helping to manage PMS and menopause symptoms.
Important notes on safety:
Passiflora incarnata can have negative interactions with prescription sedatives and blood thinners, so do not use these things together.
Passiflora incarnata is not recommended for use if you are pregnant or breastfeeding.
Dosage of this herb for children has not been studied, so it is not recommended to give it to children.
Long term use (using consistently for longer than 2 months at a time) to avoid a build-up of alkaloids, which can be toxic in very high doses. This subject is very complex, so if you are interested in knowing more, here is a good place to start.
Ways to Prepare
Passiflora incarnata’s above-ground parts (leaves, stems, flowers) can be made into a tea or tincture to harness its relaxing medicinal qualities. A safe, recommended dosage for tea is ½ gram to 2 grams of the herb as an infusion up to three times per day for up to two weeks. After two weeks, it is recommended to take a break for two days or more. For a tincture, 1-3 mL up to three times per day is recommended. For a good tincture recipe, I suggest checking out this guide from Mountain Rose Herbs, or this one from the Chestnut School of Herbs, both reputable sources for all things herbal medicine.
Passiflora incarnata is a remarkable native plant celebrated for its unique beauty, ecological benefits, and medicinal properties. Its striking, otherworldly flowers and sweet-tart fruit make it a visually appealing and functional addition to various landscapes across the eastern United States. The plant plays a crucial role in local ecosystems by providing shelter and sustenance to wildlife, including endangered butterflies, while its extrafloral nectaries attract ants that protect it from pests. This resilient plant exemplifies the beauty and utility of native flora, offering both aesthetic and practical advantages without the invasive tendencies of many exotic species.
In many areas, passionflower is still growing strong right now (during mid to late August), producing lovely flowers and delicious fruit, making now a great time to enjoy it!
Thank you for reading. I’ll share a farm update with you all very soon. I hope you all get to enjoy these coming early days of autumn!
Cheers,
Allyson
