Maypop Passionflower: How to Grow It From Seed and Cuttings

Maypop (Passionflower)

Overview

Maypop is a hardy passionflower native to the southeastern United States. The perennial vine dies to the ground in cold winters and comes back late in spring. University of Tennessee Extension (UT) calls it “an important larval food source for Gulf Fritillary and Variegated Fritillary butterflies.”

This page covers growing maypop and eating its fruit. It makes no health claims.

Here’s the short version:

1. Make sure it’s maypop, not passion fruit.
2. Sow seed outdoors, or keep it warm indoors.
3. Expect an uneven sprout. Sources differ on how long.
4. Or root a cutting or dig a sucker.
5. Give it sun and a fence away from the house, and pull suckers.
6. Eat the fruit once it’s ripe.
7. Read the safety notes.

New to growing herbs? Start Your First Medicinal Herb Garden covers sowing seeds, sunlight, and placement.

Maypop or passion fruit? Which passionflower to grow

Maypop is Passiflora incarnata. NC State Extension calls it “the hardiest of the passionflower vines” and says it’s often confused with Passiflora caerulea.

Passion fruit is Passiflora edulis, a South American fruit, and its seed advice doesn’t carry over. Buy seeds and plants by botanical name (our advice). Our safety and edibility sources cover P. incarnata only, so this page does too.

How to grow passionflower from seed

UT and the Pisa study both describe maypop seed sprouting sporadically. They split on how long it takes and how to wake it.

Collecting seed from a maypop

Got a ripe maypop from a neighbor? Here’s what to do with the seed:

• When: collect seeds “in the fall after the fruit has begun to shrivel,” says the USDA plant guide. The Lady Bird Johnson Wildflower Center says, “Check seeds when the berry is soft and yellowish.”
• Which seeds: “Mature seeds are brown in color with no traces of white” (USDA).
• Cleaning and storing: USDA says, “Wash the gelatinous covering from the seeds if they are to be stored for any length of time.” The Wildflower Center stores them “in moist sphagnum sealed, refrigerated containers.”

Sow outdoors or start indoors?

Two sources lean outdoors. The Wildflower Center says, “When sown immediately or stored, seed germination is low. Direct sowing outdoors is recommended.” USDA says, “It is best to plant the seeds directly into an outdoor seedbed,” and seedlings “may be transplanted after they have three or four leaves.”

The indoor route rests on a seed seller’s bottom-heat advice and two lab studies of warm germination. No source gives a month to sow. Fall seed? Our suggestion: sow it outdoors then, or store it and start it indoors later.

Do passionflower seeds need soaking, sanding, or cold?

Each source says something different:

• Sheffield’s Seed Company, a seed seller: “Pre-soak seed for 12 hours in warm water.” And: “Stratification: none required.”
• The Wildflower Center’s Mr. Smarty Plants suggests 24 hours in “a 5% alcohol/water solution,” which “is said to remove the chemical from the seed coat that inhibits germination.”
• A 1985 lab study by Wehtje and colleagues, as the Wildflower Center summarizes it: “Seeds that were water-leached and not exposed to light had the greatest germination percentage.”
• A 2021 University of Pisa lab study of three Italian seed lots tested an 8-hour water soak, 4 days of chilling, sanding (scarification), and a lab hormone. In one lot, “Scarification worsened germination rate, with values equal to control.” In another, “all the pre-germination treatments significantly enhanced the germination percentage.”

About sandpaper: the sandpaper steps in UF/IFAS’s propagation guide are for passion fruit (P. edulis), not maypop. For maypop, the Pisa authors, summarizing earlier studies, say mechanical scarification “never gave satisfactory results.” In their own test, sanding helped one lot and not another. None of our maypop sources calls for months of cold.

What temperature and light do maypop seeds need?

Indoors, keep it warm. Sources split on light.

• Wehtje’s study: “The most rapid germination and seedling growth occurred between 30-35 C” (86–95°F, our conversion).
• Pisa: untreated seed didn’t sprout at 77°F (25°C), and “optimal germination can be achieved at 35 °C in the dark” (95°F, our conversion).
• Sheffield’s: “It is best sown on surface of light soil or peat moss with bottom heat.”

The seller sows on the surface; both lab studies found dark better. Our advice: cover the seed lightly, or cover the tray with something that blocks light until sprouts show. A seed starter tray set with domesad holds moisture; set it somewhere warm.

How long do maypop seeds take to germinate?

• Sheffield’s: “Seed will germinate in 1-12 months at 68 degrees F.”
• UT: “Seed germination is sporadic over a long period, as much as 2 years.”
• Pisa (lab, warm, watched up to 30 days): “germination peaks usually occurred within two weeks. Beyond this time, seeds sporadically sprouted.”
• UF/IFAS (passion fruit, not maypop): scarified P. edulis seed usually begins to sprout “10 to 20 days after sowing.”

Our advice: plan for months, label the pot, and don’t toss it early.

Growing passionflower from cuttings and suckers

This is the surer route. UT says, “Cuttings and division are more predictable than seed propagation.”

Stem cuttings: the Wildflower Center says “6-8 in. stem cuttings should be taken early in the season.” USDA says, “Cuttings should be taken in the early spring. Remove the lower leaves from a 15 to 20 cm cutting before placing it in the rooting medium” (about 6 to 8 inches). None of our maypop sources names a rooting mix, a hormone, or a rooting time.

Dividing suckers: once the vine is established, “numerous suckers will appear” (Wildflower Center). USDA says, “With a shovel, separate and remove the suckers and roots. Transplant the divisions and water them immediately.” UT does this “in early fall.”

Root cuttings: NC State lists “Root Cutting” as a recommended way to propagate it, but none of our sources gives a method.

Where to plant maypop and how to grow the vine

Zones and range

NC State gives hardiness zones. The Wildflower Center gives a range line that ends in zones:

• NC State: “USDA Plant Hardiness Zone: 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b.”
• Wildflower Center: “DE to MO, s. to e. TX & FL, also in Bermuda, introduced farther n. in U.S. Zones 7 to 10.”

Sun, soil, support, spacing, and spread

Late in spring: UT says it “Emerges fairly late in spring after all danger of frost is over so don’t get discouraged if it appears to have not made it through winter.”

Sun: NC State lists full sun (“6 or more hours of direct sunlight a day”) or part shade (“Direct sunlight only part of the day, 2-6 hours”). USDA and UT say at least half a day of direct sun.

Soil: good drainage; clay and sand are fine (NC State, UT). USDA says it “will grow in heavier clay soils.” NC State warns that “in poorly drained wet soils root rot can occur, especially in the winter.” UT calls it “highly drought tolerant once established.”

Support: NC State, USDA, and UT suggest a trellis, fence, or wall. NC State adds that it “does not have to climb in order to produce flowers.” Metal garden trellis panelsad work along a fence. For a bushier vine, pinch it back “after the first growing season” (NC State) or “during their first growing season” (Wildflower Center).

Keep it off the house: NC State says, “This plant has a high flammability rating and should not be planted within the defensible space of your home.”

Space: NC State gives “Available Space To Plant: 12-24 feet.” UT gives its size as “6-8 feet height by 3-6 feet width.” Planning a small yard? Our start-your-garden guide covers sunlight and placement.

Spread: “Roots can spread aggressively. To control spread, remove suckers regularly” (UT). USDA says it “may become invasive in some regions or habitats.”

Pots: none of our sources covers containers.

For more pollinator natives, see bee balm and anise hyssop.

When does maypop flower?

• NC State: “Flowers bloom from May to July.”
• UT: “blooms June through August.”
• USDA: “The plants bloom from June to September.”
• Wildflower Center (a Texas-based database): March through November.

Fruit follows two to three months after flowering (USDA, Wildflower Center). None of our sources says how many years a seedling takes to fruit.

Harvesting maypop fruit

When is maypop fruit ripe?

USDA says the fruits “may be harvested from July to October.” NC State says they “appear from July to October and mature to a yellowish color with brown seeds in fall.” For seed cues, see collecting seed.

How to eat a maypop

NC State says, “Ripened maypops can be eaten fresh off the vine or made into jelly.” USDA says the seeds “are covered with an arillate pulp, which is the edible portion of the fruit.”

UT says, “Although fruit is edible, it is not very tasty. It can be cooked into juice or jelly.”

Parts used

• Fruit: eaten ripe, fresh or as jelly (how).
• Leaves and stems: read the safety notes first.

Safety notes

These notes are about taking passionflower, not growing it.

The cautions cover pregnancy and breastfeeding, children, surgery, medicines you take, side effects including allergy, driving, large doses, and NC State’s poison listing for the leaves and stems.

NC State Extension: “This plant has medium severity poison characteristics.” Its listing:

• “Poison Severity: Medium”
• “Poison Symptoms: Severe nausea, vomiting, drowsiness, and episodes of irregular heartbeat. Consumption of leaves in ‘herbal medicine’ is not recommended.”
• “Poison Toxic Principle: cyanogenic glycosides”
• “Causes Contact Dermatitis: No”
• “Poison Part: Leaves, Stems”
• Problems: “Poisonous to Humans, Problem for Cats, Problem for Children, Problem for Dogs, Problem for Horses”

NCCIH says:

• “Passionflower is likely safe when it’s used as a flavoring in food.”
• “Passionflower may be safe when it’s taken as a tea for up to 7 nights, and the daily use of passionflower extract may be safe for up to 8 weeks. Possible side effects include drowsiness, dizziness, and confusion.”
• “Whether it’s safe to use passionflower topically (on skin) is not known.”
• “Taking passionflower when also receiving anesthesia or other medications used before and after surgery might slow down the nervous system too much. Talk to your health care provider if you are taking passionflower within 2 weeks of a scheduled surgery.”
• “Passionflower should not be used during pregnancy as it may induce uterine contractions and possibly lead to other problems. Little is known about whether it’s safe to use passionflower while breastfeeding.”
• “If you take any type of medicine, talk with your health care provider before using passionflower or other herbal products; some herbs and medicines interact in harmful ways.”

Memorial Sloan Kettering (MSK) says, “Because animal studies show disrupted sexual behavior in male offspring, passionflower should be avoided during pregnancy. It may also interact with certain medications as well as have added effects with St. John’s wort and/or valerian.”

• Side effects: “Dizziness,” “Sedation,” “Lack of muscle coordination,” “Allergic reaction,” and “Impaired cognitive function.” And: “Large doses may result in central nervous system depression and slowed or irregular heart rhythms.”
• Case reports:
  • “A 34-year-old woman required hospital admission with symptoms of nausea, vomiting, decreased heart rate, and heart rhythm abnormalities after using a passionflower supplement.”
  • “A patient who self-medicated with valerian and passionflower while on anti-anxiety therapy experienced hand tremors, dizziness, throbbing and muscular fatigue suspected to be caused by using these products together.”
  • “Passionflower was among the 10 most frequently reported plants to cause neurotoxicity and gastrointestinal symptoms (29).”
• “Do Not Take if”:
  • “You are taking pentobarbital: Passionflower may have additive effects. Clinical relevance is not known.”
  • “You are taking benzodiazepines such as Ativan® or Valium®: Passionflower may increase the sedative effects of these medications. Clinical relevance is not known.”
  • “You are taking drugs that prolong the QT interval (eg, azithromycin, dasatinib, fingolimod): The QT interval shows the electrical activity in the heart’s lower chambers, the ventricles. Because lab analyses suggest passionflower may also prolong QT interval with large doses, it is not known whether passionflower may have added cardiac effects with these medications.”
  • “You are pregnant: Passionflower should be avoided because it may cause uterine contraction and behavioral dysfunction in offspring.”

European Medicines Agency (EMA): EMA has published a “European Union herbal monograph” on passion flower (EMA). It covers licensed EU medicines, not homegrown plants. Among its cautions:

• Age: these medicines “should only be used in adults and adolescents over the age of 12 years.”
• Pregnancy and breastfeeding: the monograph says, “In the absence of sufficient data, the use during pregnancy and lactation is not recommended.”
• Driving: “May impair ability to drive and use machines. Affected patients should not drive or operate machinery.”

Talk to your doctor or pharmacist before taking passionflower in any form if you’re pregnant, breastfeeding, taking medicine, facing surgery, or thinking of giving it to a child. These notes are for maypop only (which passionflower).

If you dry the leaves anyway

Read these first. NC State lists the leaves and stems as poisonous and says, “Consumption of leaves in ‘herbal medicine’ is not recommended.” MSK says, “Because animal studies show disrupted sexual behavior in male offspring, passionflower should be avoided during pregnancy. It may also interact with certain medications as well as have added effects with St. John’s wort and/or valerian.” Read the rest of the safety notes above.

None of our sources says when to harvest the leaves. If you still dry them, our drying guide covers the method.

Sow seed or root a cutting, give the vine a fence away from the house, and eat the fruit once it ripens to yellow. Another native to grow from seed: echinacea.

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