Blue Trumpet Vine, Bengal Clock Vine
thunbergia grandiflora
Also known as: ["Blue Trumpet Vine","Bengal Clock Vine","Skyflower"]
Overview
A vigorous, woody vine with large, showy, trumpet-shaped flowers, typically blue or lavender, native to the Himalayas and Southeast Asia.
Benefits & Perks
["long-flowering","fast growing","wildlife attractant (bees, butterflies, birds)"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Lamiales |
| Family: | Acanthaceae |
| Genus: | Thunbergia |
| Botanical Name: | Thunbergia grandiflora |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: trellis or fence in a warm, sheltered spot
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"10–35°C"}
- Hardiness: {"zones":"9–11"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent waterlogging.
- Soil Type: Well-draining potting mix with added perlite or sand for aeration.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Every 2–3 months during growing season; light pruning after flowering.
- Pruning Intensity: Moderate; remove up to one-third of growth to maintain shape and vigor.
Care Details
Ideal Sunlight Coverage:
Bright indirect light for 6–8 hours daily; can tolerate full sun with adequate water but prefers partial shade in hot climates.
Sunlight Tolerance Tips:
Acclimate gradually to intense light, protect from harsh afternoon sun, place in filtered light indoors or dappled shade outdoors.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun to partial shade
Rotate plant for even growth; use sheer curtains to filter direct sun; avoid placing near hot windows.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly until it drains from the bottom, allow soil to dry between waterings, avoid wetting foliage to prevent fungal issues.
Soil
well-draining, fertile soil with organic matter
pH: Slightly acidic to neutral (6.0–7.0).
Use a mix of potting soil, perlite, and compost; avoid heavy garden soil; ensure pots drain well.
Temperature
Thrives in 65–85°F (18–29°C); prefers warm, humid conditions; sensitive to frost.
Avoid sudden temperature changes; keep away from air conditioning vents; maintain consistent warmth during winter.
Fertilizing
every 4–6 weeks during growing season
Fertilize after watering to prevent root burn; flush soil occasionally to prevent salt buildup; reduce feeding in dormant periods.
Propagation
Methods
Stem cuttings in water or soil; softwood cuttings root most readily.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting, remove lower leaves, dip in rooting hormone (optional), plant in moist medium, keep warm and humid.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm, humid environment with indirect light; maintain 70–75°F (21–24°C) and high humidity.
Medium
Well-draining potting mix or water with occasional root hormone application.
Hormone
Optional but recommended for faster rooting.
Timeline
Roots typically form in 2–4 weeks; new growth appears in 6–8 weeks.
Tools Needed
Pruning shears, rooting hormone, small pots, plastic bags or propagator, misting bottle.
Quick Tips
Use healthy, non-flowering stems; keep soil consistently moist but not waterlogged; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Pinch back tips, cut back leggy stems, remove dead or diseased growth, shape as needed.
Pruning Plan
Regular pruning to control size, encourage bushier growth, and promote flowering.
Tools
Pruning shears, sharp knife, gloves, disinfectant.
Checklist
Disinfect tools, prune during active growth, remove dead/diseased parts, shape plant, clean up debris.
Repotting Guide
Best Season
Spring, before new growth begins.
Pot Size
One size larger pot; ensure it has drainage holes.
Method
Remove plant gently, trim roots if necessary, place in new pot with fresh soil, water thoroughly, place in shade for a few days.
Suggestions
Repot every 2–3 years or when roots fill the pot; beneficial for growth and flowering.
Checklist
Choose appropriate pot, prepare new soil, trim roots if needed, water after repotting, adjust care temporarily.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture, water deeply, ensure drainage, avoid wetting leaves, adjust for season.
How to Apply Water Properly
Water directly at the root zone, apply until water drains from the bottom, ensure excess water exits the pot, water in the morning to reduce evaporation and fungal risk.
Watering Schedule Tips
Water deeply once the top inch of soil feels dry; reduce frequency in winter to prevent root rot.
Soil Improvement
Add perlite or coarse sand for drainage, incorporate organic matter like compost for fertility, ensure pots have drainage holes.
Temperature Stress Management
Signs of Temperature Issues
Yellowing leaves, leaf drop, stunted growth, or wilting in extreme heat or cold.
Cold Stress
Growth slows or halts, leaves may turn yellow or brown, plant becomes more susceptible to pests and diseases.
Solution: Move to a warmer location, protect from drafts, cover with a frost cloth if temperatures drop below 50°F (10°C).
Hot Stress
Wilting, leaf scorch, reduced flowering, or leaf drop due to excessive heat and water loss.
Solution: Provide shade during peak sun, increase watering frequency, mist leaves in the morning to boost humidity.
Fertilizing Guide
Fertilizing Checklist
Check fertilizer type, dilute correctly, apply during active growth, avoid winter feeding, flush soil periodically.
Fertilizing Method
Use balanced liquid fertilizer diluted to half strength every 4–6 weeks during growing season (spring to fall); avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats may experience mild gastrointestinal irritation if they consume the seeds or roots of Thunbergia grandiflora. The toxicity is generally low, but ingestion should be avoided.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of Thunbergia grandiflora seeds and roots may lead to mild gastrointestinal upset. The effects are typically not life-threatening but can cause discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicThunbergia grandiflora contains compounds that can cause mild gastrointestinal distress when ingested. The physiological impact is generally limited to irritation of the digestive tract.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: How do I prune Thunbergia grandiflora?
A: Prune in late winter or early spring to control growth and encourage flowering.
Q: Does Thunbergia grandiflora attract pollinators?
A: Yes, it is highly attractive to bees, butterflies, and hummingbirds.
Q: Is Thunbergia grandiflora invasive?
A: It can be invasive in some regions, so it is best grown in containers or controlled environments.
Quick Reference
| Family: | Acanthaceae |
| Care: | moderate |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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