How to Grow Heavenly Blue
Wikimedia Commons
Heavenly Blue
Ipomoea tricolor 'Heavenly Blue'
vineHeavenly Blue is a stunning morning glory cultivar renowned for its large, vivid sky-blue trumpet flowers that open in early morning and close by afternoon. This vigorous annual climbing vine can reach 10-15 feet in a single season, making it ideal for covering trellises, arbors, and fences. The heart-shaped green foliage provides a perfect backdrop for the prolific, dazzling blue blooms.
When should you plant Heavenly Blue in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Heavenly Blue timeline · Pittsburgh, PA (Zone 6b)
-
Plant Heavenly Blue
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
Harvest Heavenly Blue
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Heavenly Blue dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-11; grown as annual in cooler climates, perennial in zones 10-11
Sign up free to see if Heavenly Blue grows in your zone — and get a personalized planting timeline.
Get my Heavenly Blue timeline →Growth Stages
Seed Preparation & Germination
7-14 daysSeeds are hard-coated. Scarify or soak overnight to improve water absorption. Germination occurs in 7-14 days at 70-75°F.
Start seeds indoors 4-6 weeks before last frost, or direct sow after all frost danger has passed. Use warm soil and maintain consistent moisture.
Seedling & Vine Establishment
3-4 weeksYoung plants develop heart-shaped cotyledons followed by true leaves. Vines begin climbing or trailing as they establish.
Provide support structure early. Keep soil consistently moist but not waterlogged. Thin or space seedlings 12 inches apart. Fertilize lightly every 2-3 weeks.
Vegetative Growth
3-5 weeksVigorous vine growth with increasing foliage coverage. Plant rapidly climbs support structure and fills out the growing space.
Guide vines onto trellis or support as needed. Reduce nitrogen fertilizer to encourage flowering rather than excessive leaf growth. Water during dry periods.
Flowering & Blooming
8-12 weeks (or until frost)Abundant sky-blue trumpet flowers open in early morning (typically 5-7 AM) and close by mid-afternoon. Flowers are 2-3 inches wide and appear daily throughout the season.
Flowers close naturally in heat and afternoon sun—this is normal. Deadheading spent flowers encourages continued blooming. Reduce watering slightly to promote more flowers.
Seed Production & Season's End
3-4 weeks before frostAfter pollination, seed pods develop. Frost kills the plant in cool climates; seeds mature and dry on the vine. Plant dies back naturally.
Allow some flowers to set seed if you want self-seeding next year, or deadhead for continuous blooms. Allow mature seed pods to dry on vine before collecting.
Common Pests
-
Hand-pick early morning; use neem oil or pyrethrin spray; encourage native predators
-
Spray with water jet to dislodge; use insecticidal soap; introduce ladybugs
-
Increase humidity by misting; spray with neem oil; ensure adequate watering to reduce plant stress
-
Yellow sticky traps; insecticidal soap; neem oil spray
-
and
Hand-pick at night; copper tape barriers; beer traps; diatomaceous earth
Uses
Seeds in Traditional Medicine
CulinaryMorning glory seeds contain lysergic acid amide (LSA), compounds used historically in some cultures for ceremonial purposes. The seeds have been traditionally used in small quantities in herbal preparations. [source]
Ornamental Screen & Shade
HouseholdThe vigorous vine growth and dense foliage create living screens on fences, trellises, and arbors, providing shade and privacy while displaying stunning blue flowers throughout summer and fall. [source]
Pollinator & Hummingbird Plant
WildlifeThe vibrant flowers attract bees, butterflies, and hummingbirds throughout the growing season, providing essential nectar and pollen sources during summer months. [source]
Cut Flower & Floral Arrangements
CraftAlthough morning glory flowers close by afternoon, they can be harvested early in the morning for same-day floral arrangements and bouquets, bringing fresh sky-blue color to indoor displays. [source]
Quick Garden Coverage
HouseholdHeavenly Blue's rapid growth (reaching 10-15 feet in a season) makes it ideal for quickly covering unsightly structures, screening unwanted views, or establishing temporary garden features. [source]
Harvest Tips
Morning glory is grown for ornamental flowers, not harvested like food crops. Pinch back growing tips in early season to encourage branching and fuller coverage. Deadhead spent flowers regularly to extend blooming season. For seeds, allow some flowers to mature into papery seed pods, then collect and dry completely before storing in cool, dry conditions.
Fun Facts
- 🌱 Morning glory flowers open in response to light changes at dawn and close in the afternoon or during cloudy weather, a phenomenon called nyctinasty. The flower opening and closing is controlled by turgor pressure changes in specialized hinge cells at the base of the flower.
- 🌱 Heavenly Blue was developed in Japan and has become one of the most popular morning glory cultivars worldwide. The cultivar's stunning color and prolific blooming habit made it a favorite in Victorian gardens and it remains a beloved heirloom variety today.
- 🌱 A single Heavenly Blue plant can produce hundreds of flowers throughout the growing season. In optimal conditions with proper deadheading, a mature vine may produce 20-30 new flowers daily during peak blooming season.
Gardening Terms
New to gardening? Learn about terms used in this guide:
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Heavenly Blue planting timeline
Tell us your zip code and we'll calculate exactly when to start Heavenly Blue seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Heavenly Blue timeline →