How to Grow Imperial Blue
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Imperial Blue
Ipomoea tricolor 'Imperial Blue'
vineImperial Blue is a stunning morning glory cultivar featuring deep blue flowers with white throats that open in early morning hours. This fast-growing vine is a favorite ornamental for trellises, arbors, and fences, reaching 8-10 feet in a single season. The heart-shaped foliage provides lush green coverage while the prolific blooms attract pollinators throughout summer and fall.
When should you plant Imperial Blue in your zone?
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Example Imperial Blue timeline · Pittsburgh, PA (Zone 6b)
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Plant Imperial Blue
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 Imperial Blue
Around Jun 1≈ 45 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Imperial Blue dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-11; grown as an annual in colder zones, perennial in zones 9-11
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Seed Germination
7-14 daysSmall seedlings with two cotyledons emerge from soil, developing true leaves within 1-2 weeks
Keep soil consistently moist but not waterlogged. Provide warmth (70-75°F optimal). Seeds germinate faster if scarified or soaked 12-24 hours before planting.
Vegetative Growth
3-4 weeksVines rapidly produce heart-shaped leaves and develop climbing tendrils or twining stems; plant can grow 6+ inches weekly in peak season
Provide sturdy support structure early. Avoid excessive nitrogen to prevent foliage at expense of blooms. Water regularly as growth accelerates.
Flowering Initiation
1-2 weeksFirst flower buds appear at leaf axils; buds are tightly spiraled green structures that gradually enlarge
Maintain consistent watering and light. Once flowering begins, reduce nitrogen and maintain moderate moisture. Stake or guide vines onto support.
Peak Blooming
8-12 weeks (until frost or dormancy)Deep blue flowers with white throats open in early morning (typically 5-8 AM) and close by midday. Hundreds of blooms may be present simultaneously on mature vines.
Deadhead spent flowers if desired to encourage continued production (though self-cleaning). Keep watering consistent. Apply balanced fertilizer every 2-3 weeks if growth slows.
Seed Production & Decline
2-4 weeks before frostAs temperatures cool (fall/frost), flowering slows. Seed pods develop from pollinated flowers; vines eventually decline with first hard frost in zones below 9
Allow some flowers to set seed if you wish to collect seeds for next year. Cut back dead growth after frost. In warm zones, may continue blooming year-round.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with water to dislodge; use insecticidal soap or neem oil in severe cases. Increase humidity around plants.
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Use yellow sticky traps; spray with insecticidal soap or neem oil. Encourage natural predators.
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Hand-pick in early morning; use pheromone traps away from plant. Apply spinosad if infestation is severe.
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Blast off with strong water spray; apply insecticidal soap or neem oil. Attract ladybugs and parasitic wasps.
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and
Remove by hand, especially at night. Use copper tape barriers. Beer traps or diatomaceous earth around base.
Uses
Ornamental Trellis & Arbor Coverage
HouseholdImperial Blue morning glories are ideal for quickly covering vertical structures, creating living screens and shade. The prolific blue flowers provide stunning seasonal color from summer through fall frost. [source]
Pollinator Attraction
WildlifeThe abundant nectar and early-opening flowers attract bees, butterflies, and hummingbirds, making it an excellent addition to pollinator gardens. A single mature plant can support dozens of beneficial insects daily. [source]
Seed Saving & Propagation
CraftImperial Blue produces viable seeds that can be collected and stored for the following season, making it economical for gardeners. Seeds germinate readily and can be shared with fellow gardeners. [source]
Traditional Use & Ethnobotany
MedicinalMorning glory species have historical use in traditional medicine in Mexico and Central America, though Imperial Blue is primarily grown ornamentally. Some compounds in morning glories have been studied for biological activity. [source]
Natural Shade Provider
HouseholdFast-growing vines create natural cooling shade on pergolas and fences, reducing heat gain on buildings while providing beautiful seasonal color. The dense foliage provides privacy screens. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Morning glories are grown for ornamental flowers, not harvested for food. Enjoy flowers in early morning hours when they are fully open and vibrant blue. To collect seeds, allow flowers to fade and dry on vine; collect mature seed pods before heavy rain (typically late summer/fall) and dry indoors. Seeds remain viable for 2-3 years in cool, dry storage.
Fun Facts
- 🌱 Morning glory flowers open in the early morning (typically 5-8 AM) and close by midday or early afternoon, a phenomenon called nyctinasty. This daily rhythm ensures fresh flowers throughout the blooming season.
- 🌱 Imperial Blue can grow up to 3 feet per month during peak growing season, making it one of the fastest-growing ornamental vines. A single vine can produce hundreds of flowers in a season.
- 🌱 The name 'morning glory' comes from the flower's habit of blooming at sunrise. Some cultures consider these flowers symbols of love and affection, while in others they represent mortality due to their short daily lifespan.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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