North America Non-native Plant

Scarletfruit Passionflower

Botanical name: Passiflora foetida var. isthmia

USDA symbol: PAFOI

Life cycle: annual

Habit: vine

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Scarletfruit Passionflower: An Uncommon Annual Worth Knowing About Meet the scarletfruit passionflower (Passiflora foetida var. isthmia), a rather mysterious member of the passion vine family that’s quietly making its presence known in American gardens. While you might not find this annual climbing herb at your local nursery, it’s worth understanding ...

Scarletfruit Passionflower: An Uncommon Annual Worth Knowing About

Meet the scarletfruit passionflower (Passiflora foetida var. isthmia), a rather mysterious member of the passion vine family that’s quietly making its presence known in American gardens. While you might not find this annual climbing herb at your local nursery, it’s worth understanding what makes this particular variety special – and whether it belongs in your landscape.

What Exactly Is Scarletfruit Passionflower?

The scarletfruit passionflower is an annual forb herb, meaning it completes its entire life cycle in just one growing season. Unlike its perennial cousins that return year after year, this climbing beauty puts on a one-season show before setting seed and calling it quits. As a vascular plant without significant woody tissue, it climbs and sprawls with herbaceous stems that remain soft and flexible throughout the growing season.

Where You’ll Find It Growing

Currently, this particular variety has been documented growing in Maryland, where it has established itself as a non-native species that reproduces on its own in the wild. This means it’s not originally from North America but has found conditions suitable enough to naturalize without human intervention.

Should You Grow Scarletfruit Passionflower?

Here’s where things get interesting – and a bit complicated. While this plant isn’t listed as invasive or noxious, its status as a non-native species that readily self-seeds in the wild should give gardeners pause for thought.

Reasons You Might Consider It:

  • Unique annual climbing habit offers single-season interest
  • Part of the fascinating passion vine family
  • Not currently classified as problematic or invasive

Why You Might Want to Skip It:

  • Limited ecological benefits compared to native alternatives
  • Very little information available about growing requirements
  • Annual nature means replanting each year
  • Potential to spread beyond intended garden areas

Native Alternatives to Consider

Before settling on scarletfruit passionflower, consider these native climbing alternatives that offer similar benefits with greater ecological value:

  • Wild grape (Vitis species) – provides food for wildlife and beautiful fall color
  • American groundnut (Apios americana) – nitrogen-fixing vine with fragrant flowers
  • Virgin’s bower (Clematis virginiana) – delicate white flowers and fluffy seed heads
  • Trumpet honeysuckle (Lonicera sempervirens) – beloved by hummingbirds

Growing Information (Limited)

Unfortunately, specific growing information for Passiflora foetida var. isthmia is quite scarce. What we do know is that as an annual herb, it likely prefers:

  • Warm growing conditions typical of passion vines
  • Some form of support for its climbing habit
  • Well-draining soil
  • Protection from harsh winds

The Bottom Line

The scarletfruit passionflower remains something of an enigma in the gardening world. While it’s not a bad plant per se, the combination of limited growing information, non-native status, and abundance of superior native alternatives makes it a questionable choice for most gardens.

If you’re drawn to unusual climbing annuals, consider exploring the many native vines that offer proven benefits to both gardeners and local ecosystems. Your local wildlife – and your garden – will thank you for choosing plants that truly belong in your landscape.

Scarletfruit Passionflower

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Violales

Family

Passifloraceae Juss. ex Roussel - Passion-flower family

Genus

Passiflora L. - passionflower

Species

Passiflora foetida L. - fetid passionflower

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA