How to Grow Black Knight
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Black Knight
Ipomoea purpurea 'Black Knight'
vineBlack Knight is a stunning cultivar of morning glory featuring deep, dark purple (nearly black) flowers that bloom profusely throughout the growing season. This vigorous annual vine climbs readily via twining stems and produces heart-shaped foliage that provides an attractive backdrop for the dramatic blooms. It's prized as an ornamental climber for trellises, arbors, and fences.
When should you plant Black Knight in your zone?
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Example Black Knight timeline · Pittsburgh, PA (Zone 6b)
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Plant Black Knight
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 Black Knight
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Black Knight dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives nationwide as an annual; grown as a warm-season annual in all zones
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Seedling
2-3 weeksSmall plants with rounded cotyledons and developing true leaves; delicate and tender.
Start seeds indoors 4-6 weeks before last frost, or direct sow after frost danger passes. Soak seeds overnight to improve germination. Provide warm soil (70-75°F) and keep moist.
Vegetative Growth
3-4 weeksRapid vine elongation with heart-shaped leaves developing along twining stems. Plant becomes bushy and leafy.
Provide climbing structure (trellis, stake, or arbor). Train vines as desired. Fertilize lightly with balanced fertilizer every 3-4 weeks. Pinch growing tips if bushier form is desired.
Budding
1-2 weeksFlower buds form at leaf axils along the vines; buds appear tight and unopened.
Maintain consistent moisture and light. Continue light fertilizing, focusing on phosphorus to encourage blooms. Ensure adequate sunlight.
Flowering
8-10 weeks (or until frost)Deep purple flowers open in morning, typically closing by afternoon. Blooms are funnel-shaped, 2-3 inches across, nearly black in color.
Deadheading is optional; the plant blooms continuously regardless. Water regularly during hot weather. Reduce nitrogen fertilizer to avoid excessive leaf growth at the expense of flowers.
Seed Production
Ongoing until frostAfter flowering, round seedpods develop containing dark seeds. Plant continues producing new flowers while seeds mature.
Allow some flowers to set seed for self-sowing next year, or harvest seed pods before frost if you want to collect seeds. Remove spent seed pods if you prefer continuous blooming.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick in early morning, use row covers on young plants, or apply insecticidal soap if infestation is heavy
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Increase humidity, spray foliage with water, use insecticidal soap, or apply neem oil
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Use yellow sticky traps, spray with insecticidal soap, or apply neem oil
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Rinse with strong water spray, introduce beneficial insects, use insecticidal soap, or apply neem oil
Uses
Ornamental Climbing Structure
CraftBlack Knight is ideal for creating dramatic vertical interest in gardens, covering trellises, arbors, fences, and pergolas with its vigorous vines and stunning deep purple flowers. [source]
Pollinator Attraction
WildlifeThe abundant flowers attract butterflies, bees, and hummingbirds, making it valuable for supporting pollinator populations throughout the blooming season. [source]
Cut Flower Arrangements
CraftFresh morning glory blooms can be cut in early morning when flowers first open and used in floral arrangements, though they typically close by afternoon. [source]
Privacy and Screening
HouseholdThe dense foliage and vigorous growth habit make Black Knight excellent for creating natural privacy screens and windbreaks on otherwise bare structures. [source]
Traditional Ethnobotanical Use
MedicinalIpomoea species have been used in traditional medicine in various cultures, though modern medicinal applications are limited and seeds contain compounds requiring careful handling. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Black Knight morning glory is grown for ornamental flowers rather than harvest. Enjoy the blooms in situ on the vine. If collecting seeds, allow pods to dry completely on the plant (turn brown and papery), then harvest and store in a cool, dry place for next season's planting.
Fun Facts
- 🌱 Morning glory flowers open in the early morning as the sun rises and typically close by early afternoon, earning their common name. This daily cycle continues throughout the blooming season.
- 🌱 Black Knight is an annual vine that can grow 6-10 feet tall in a single season, making it one of the fastest-growing ornamental vines for quick garden coverage.
- 🌱 The plant readily self-seeds if allowed to mature, potentially becoming a volunteer in gardens the following year—some gardeners consider it mildly invasive in warm climates where it can persist.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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