How to Grow Royal Robe
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Royal Robe
Ipomoea purpurea 'Royal Robe'
vineRoyal Robe is a stunning cultivar of morning glory featuring deep purple-blue flowers with a contrasting white throat. This vigorous annual vine climbs quickly and produces abundant blooms throughout the growing season, making it a dramatic addition to trellises, arbors, and garden screens.
When should you plant Royal Robe in your zone?
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Example Royal Robe timeline · Pittsburgh, PA (Zone 6b)
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Plant Royal Robe
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 Robe
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Royal Robe dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-11 as an annual; perennial in zones 10-11
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Seedling
2-3 weeksSmall heart-shaped cotyledons emerge; first true leaves develop with characteristic morning glory shape.
Keep soil warm (65-75°F) and consistently moist. Provide bright light. Thin seedlings to proper spacing.
Vegetative Growth
3-4 weeksRapid vine elongation with increasing leaf production. Plant climbs actively along support structures.
Train vines onto trellis or support. Water regularly. Fertilize every 2-3 weeks with balanced fertilizer. Remove any damaged growth.
Bud Formation
1-2 weeksFlower buds begin appearing at leaf axils; buds are tightly coiled and elongated.
Maintain consistent watering. Reduce nitrogen fertilizer to encourage more blooms. Continue training vines upward.
Flowering
6-10 weeks until frostLarge, funnel-shaped deep purple-blue flowers open in early morning, closing in afternoon heat. White or pale throat contrasts beautifully. Continuous blooming occurs daily.
Water deeply and regularly. Deadheading spent flowers encourages continued blooming (though not necessary). Support heavy vine weight. Watch for pests.
Seed Set & Decline
Until first frostIf not deadheaded, flowers fade and develop into round seed capsules. Plant productivity slows as frost approaches.
Allow some flowers to mature into seeds if you want to collect for next year. Plant dies at first frost in cold zones.
Common Pests
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Spray with insecticidal soap or neem oil. Increase air circulation. Use yellow sticky traps. Control with reflective mulches.
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Mist foliage regularly to increase humidity. Spray with neem oil or horticultural oils. Prune heavily infested areas.
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Spray with strong water jet to dislodge. Use insecticidal soap. Encourage beneficial insects like ladybugs. Apply neem oil as needed.
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Hand-pick beetles early morning. Use pheromone traps away from plants. Apply neem oil for larvae control. Remove affected foliage.
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Inspect regularly and remove by hand. Spray with horticultural oil in dormant season. Use neem oil during growing season.
Uses
Garden Screening & Vertical Beauty
OrnamentalRoyal Robe quickly covers trellises, arbors, and garden screens with lush foliage and stunning purple-blue flowers. The vigorous growth habit and prolific blooming make it perfect for creating privacy screens or adding dramatic vertical interest to landscapes. [source]
Pollinator Support
WildlifeThe bright morning glory flowers attract hummingbirds, bumblebees, and other pollinators, providing valuable nectar resources throughout the growing season. [source]
Seed Collection & Propagation
CraftRoyal Robe produces viable seeds in abundance, allowing gardeners to collect seeds for next season's planting. This makes it economical for large-scale plantings and a rewarding project for seed-saving enthusiasts. [source]
Fresh Cut Flowers
HouseholdPick flowers early morning when they're freshly opened for attractive additions to bouquets or table arrangements. They'll close by afternoon but are beautiful in cut arrangements with morning glory stems and foliage. [source]
Harvest Tips
Morning glories are ornamental vines; harvest refers to collecting seeds rather than cutting flowers. Seed pods mature in late summer/fall—allow flowers to fade and seed pods to brown on the vine. Collect seed capsules before frost, dry indoors for 1-2 weeks, then extract seeds and store in cool, dry conditions. For continuous blooms, deadhead spent flowers daily or several times weekly.
Fun Facts
- 🌱 Morning glories open at dawn and close by afternoon, giving them their common name. This behavior is driven by circadian rhythms controlled by light and temperature changes.
- 🌱 Royal Robe and other Ipomoea purpurea cultivars are not true morning glories but closely related; true morning glories (Ipomoea nil) are a different species. However, they share similar growing requirements and habits.
- 🌱 Seeds of morning glories have hard seed coats and benefit from scarification—lightly filing the seed coat or soaking in warm water overnight—to improve germination rates by up to 50%.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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