Scarlet larkspur
delphinium cardinale
Also known as: ["Cardinal larkspur","Red larkspur"]
Overview
A tall, herbaceous perennial known for its striking scarlet flowers and toxic properties.
Benefits & Perks
["long-flowering","wildlife attractant (bees, butterflies, birds)","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Ranunculales |
| Family: | Ranunculaceae |
| Genus: | Delphinium |
| Botanical Name: | Delphinium cardinale |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: garden bed with good air circulation, protected from strong winds
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–30°C"}
- Hardiness: {"zones":"8–10"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Well-draining to fast-draining; avoid heavy clay soils.
- Soil Type: Rich, loamy soil with good organic matter; well-draining to prevent waterlogging.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: After flowering; lightly prune throughout the growing season to remove dead or weak stems.
- Pruning Intensity: Light to moderate; focus on removing spent flowers and thinning crowded stems.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily) in cooler climates; partial shade in hot regions, especially afternoon shade.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from harsh midday sun in hot climates; provide dappled shade during peak heat.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun to partial shade
Morning sun is ideal; avoid intense afternoon sun in warm areas; rotate pots for even light exposure.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but infrequently to encourage deep roots; avoid waterlogging; ensure good drainage.
Soil
well-draining, loamy soil with organic matter
pH: Slightly acidic to neutral (pH 6.0–7.0).
Ensure good drainage; enrich with organic matter; maintain consistent moisture levels.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cooler nights and can handle light frosts.
Protect from extreme heat and cold; maintain consistent temperatures; avoid placing near heat sources or drafty windows.
Fertilizing
every 4–6 weeks during growing season
Fertilize sparingly to avoid root burn; apply after watering to prevent salt buildup; stop in late summer to prepare for dormancy.
Propagation
Methods
Stem cuttings or division; stem cuttings are more common for home growers.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings just below a node.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity with a propagator or plastic cover.
Best Time: Early spring or late summer when the plant is actively growing but not under stress.
Environment
Warm (65–75°F or 18–24°C), humid (70–80% relative humidity), and bright indirect light.
Medium
Well-draining mix of peat, perlite, and sand; or a specialized cutting mix.
Hormone
Recommended to use rooting hormone powder or gel for higher success rates.
Timeline
Roots may develop in 3–6 weeks; establishment can take an additional 2–3 months.
Tools Needed
Sharp pruners, rooting hormone, small pots, misting bottle, plastic wrap or propagator.
Quick Tips
Use healthy, non-flowering stems; maintain consistent moisture; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Deadhead by cutting flower spikes just above a leaf node; trim leggy stems to an outward-facing bud.
Pruning Plan
Remove spent flower spikes to encourage reblooming and prevent seed formation; trim leggy growth to maintain shape.
Tools
Sharp, clean pruners or scissors; gloves to protect hands from prickles.
Checklist
Sterilize tools; prune after flowering; cut above a leaf node; remove dead or damaged growth.
Repotting Guide
Best Season
Early spring before new growth begins; avoid repotting during flowering or dormancy.
Pot Size
Increase pot size by 2–3 inches in diameter; ensure the new pot has drainage holes.
Method
Gently remove the plant; trim any circling roots; place in a slightly larger pot with fresh, well-draining soil; water thoroughly after repotting.
Suggestions
Repot every 2–3 years or when roots fill the container; beneficial for rejuvenation and fresh soil.
Checklist
Choose appropriate pot size; prepare fresh soil mix; trim roots if necessary; water after repotting; place in appropriate light.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure drainage; avoid wetting foliage.
How to Apply Water Properly
Water at the base of the plant, soaking the root zone to a depth of 6–8 inches, allowing excess to drain away. Water early in the day to minimize leaf wetness.
Watering Schedule Tips
Water deeply once the top inch of soil is dry, typically every 7–10 days in warm weather, reducing frequency in cool months. Adjust based on rainfall and humidity.
Soil Improvement
Add compost or well-rotted manure for fertility; incorporate perlite or sand for drainage; use mulch to retain moisture and suppress weeds.
Temperature Stress Management
Signs of Temperature Issues
Wilting, leaf scorch, stunted growth, or bud drop in excessive heat; leaf discoloration or slow growth in cold stress.
Cold Stress
Slows growth and can cause leaf damage or dieback if temperatures drop below 20°F (-6°C) without protection.
Solution: Mulch heavily around the base; cover with frost cloth during freezes; move containers to sheltered locations.
Hot Stress
Leaves may wilt, scorch, or drop; flowering may be reduced; growth can become stunted.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture; improve air circulation.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during growing season; water before fertilizing; avoid contact with foliage.
Fertilizing Method
Use a balanced, water-soluble fertilizer diluted to half strength every 4–6 weeks during active growth (spring and summer); avoid fertilizing in fall and winter.
Common Problems & Solutions
Toxicity Warning
Cats
ToxicCats are highly sensitive to the diterpene alkaloids present in Delphinium cardinale. Even small amounts can cause severe toxicity, affecting the nervous system and leading to critical health issues. The plant poses a significant risk to feline health.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
ToxicThe diterpene alkaloids in Delphinium cardinale are equally toxic to dogs, causing severe neurological and gastrointestinal distress. The toxins disrupt normal muscle function and can lead to life-threatening complications if not treated promptly.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
ToxicDelphinium cardinale contains diterpene alkaloids, which are highly toxic to humans. These compounds interfere with neuromuscular transmission, leading to severe physiological effects. Ingestion can result in significant systemic toxicity, affecting the nervous system, cardiovascular system, and gastrointestinal tract.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Delphinium cardinale toxic to pets?
A: Yes, it is toxic to both dogs and cats.
Q: How often should I water Delphinium cardinale?
A: Water moderately, allowing the soil to dry slightly between waterings.
Q: Does Delphinium cardinale attract wildlife?
A: Yes, it attracts bees, butterflies, and birds.
Quick Reference
| Family: | Ranunculaceae |
| Care: | moderate |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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