How to Grow Royal Clock
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Royal Clock
Passiflora edulis
vineRoyal Clock is a vigorous passionflower vine prized for its stunning purple and white corona of filaments and highly fragrant flowers. It produces edible passion fruits and is valued both as an ornamental specimen and for fruit production. The plant is a tropical to subtropical climber that can grow 15-20 feet in a single season.
When should you plant Royal Clock in your zone?
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Example Royal Clock timeline · Pittsburgh, PA (Zone 6b)
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Plant Royal Clock
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Royal Clock
Around Oct 14≈ 180 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Royal Clock dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 9b-11; can be grown in containers and brought indoors in colder climates
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Seedling
2-3 weeksTiny sprouted seedlings with cotyledons and first true leaves emerging
Keep soil warm (70-75°F) and moist. Provide bright indirect light. Use grow lights if needed.
Vegetative Growth
6-8 weeksRapid vine development with heart-shaped leaves and expanding shoots; no flowers yet
Provide sturdy support structure or trellis. Fertilize monthly with balanced fertilizer. Prune side shoots to encourage main vine development.
Flowering
8-12 weeks (continuous through season)Appearance of spectacular purple and white flowers with distinctive crown of filaments; flowers open in afternoon
Maintain consistent watering and humidity. Hand-pollinate flowers with small brush for better fruit set. Reduce nitrogen fertilizer; apply phosphorus-rich fertilizer.
Fruiting
8-10 weeks per fruitSmall green fruits develop behind faded flowers; fruits gradually enlarge and change color from green to dark purple
Continue regular watering. Support heavy fruit clusters with soft ties. Do not pick too early; wait for fruits to fully mature and wrinkle slightly.
Harvest/Dormancy
Variable; dormancy 2-3 months in cooler zonesRipe dark purple wrinkled fruits ready for harvest; plant may slow growth in winter
Harvest ripe fruits. In winter, reduce water and fertilizer. Prune back vines by one-third to maintain shape and encourage next season's growth.
Common Pests
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Remove affected leaves; spray neem oil or insecticidal soap on undersides of leaves
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Increase humidity; spray water on foliage; use miticide if severe
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Spray neem oil; use rubbing alcohol on cotton swabs for small infestations
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Prune heavily infested branches; spray horticultural oil during dormant season
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Tolerate on the plant if possible; this is beneficial; use row covers only if absolutely necessary
Uses
Fresh Passion Fruit & Juice
CulinaryThe pulp inside mature fruits is tart-sweet and aromatic, eaten fresh with a spoon or used in juices, smoothies, and cocktails. High in vitamin C and antioxidants. [source]
Desserts & Preserves
CulinaryPassion fruit pulp is used in jams, jellies, mousses, cakes, and ice cream, adding exotic flavor and natural pectin. [source]
Herbal Tea & Nervous System Support
MedicinalThe leaves and flowers have been traditionally used to make calming herbal tea with purported mild sedative properties, used to aid sleep and reduce anxiety. [source]
Ornamental Beauty & Pollinator Attraction
OrnamentalThe dramatic purple and white flowers with intricate corona filaments make this a stunning landscape specimen. Flowers attract bees, butterflies, and hummingbirds. [source]
Butterfly Host Plant
WildlifeEssential host plant for passion vine butterfly (Heliconius sara and related species) caterpillars; supporting butterfly conservation. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest fruits when they are dark purple and slightly wrinkled, 60-80 days after flowering. Ripe fruits will fall from the vine or be easily picked. Cut fruits open and scoop out the seed-encased pulp to eat fresh, make juice, or strain for seeds. The fruit is ready when it yields slightly to gentle pressure.
Fun Facts
- 🌱 Royal Clock flowers have an intricate 'clock-like' corona of colorful filaments that earn it its name; these filaments appear to radiate like clock hands
- 🌱 Passion fruit flowers are pollinated primarily by carpenter bees and other large bees that use the flowers' structure as a landing pad
- 🌱 The fruit is called 'passion fruit' because Spanish missionaries saw symbolic religious significance in the flower's complex structure, relating it to the passion of Christ
Gardening Terms
New to gardening? Learn about terms used in this guide:
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