Amethyst Sea Holly
eryngium amethystinum
Also known as: ["Sea Holly","Amethyst Eryngium"]
Overview
A striking perennial with spiky, silvery-blue flowers and foliage, native to the Mediterranean region.
Benefits & Perks
["long-flowering","deer resistant","wildlife attractant (bees, butterflies, birds)","drought tolerant","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Apiales |
| Family: | Apiaceae |
| Genus: | Eryngium |
| Botanical Name: | Eryngium amethystinum |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: border plantings, rock gardens, or containers in full sun
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"10–35°C"}
- Hardiness: {"zones":"7–10"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent root rot.
- Soil Type: Well-draining, sandy loam with some organic matter; avoid heavy clay soils.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: As needed throughout the growing season; more frequently if used in floral arrangements.
- Pruning Intensity: Light to moderate; avoid heavy pruning unless necessary to control size.
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade; 6–8 hours of direct sunlight per day; adjust to partial shade in intense summer heat.
Sunlight Tolerance Tips:
Acclimate plants gradually to intense sunlight; protect from harsh afternoon sun in hot climates; ensure adequate ventilation if grown indoors.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun to partial shade
Rotate plant regularly for even growth; provide shade during peak summer heat; monitor for signs of sunburn.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but infrequently; ensure soil dries between waterings; avoid overhead watering to prevent fungal issues.
Soil
well-draining, sandy loam with moderate organic matter
pH: Slightly acidic to neutral (pH 6.0–7.0).
Use a cactus or succulent mix as a base; ensure pots have drainage holes; avoid overwatering in heavy soils.
Temperature
Prefers warm temperatures between 65–85°F (18–29°C); tolerates mild frosts but thrives in warmth.
Protect from frost; provide shade in extreme heat; maintain consistent temperatures for optimal growth.
Fertilizing
every 4–6 weeks during growing season with balanced liquid fertilizer
Apply fertilizer after watering to prevent root burn; stop fertilizing in late autumn; use a balanced formula for best results.
Propagation
Methods
Stem cuttings or division; stem cuttings are more common for home growers.
Step-by-Step Propagation Guide
- Take a 4–6 inch cutting.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Keep moist and warm.
Best Time: Late spring to early summer when the plant is actively growing.
Environment
Warm, humid environment with indirect light; maintain consistent moisture.
Medium
Well-draining potting mix with perlite or sand; can also root in water initially.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots typically form in 3–6 weeks; new growth may take an additional 2–3 months.
Tools Needed
Pruning shears, rooting hormone, small pots, well-draining medium, misting spray bottle.
Quick Tips
Use healthy, non-flowering stems; maintain high humidity around cuttings; avoid direct sunlight during rooting.
Pruning & Repotting
Pruning Guide
Method
Pinch back growing tips; cut stems just above a leaf node or lateral branch.
Pruning Plan
Remove dead or damaged foliage to maintain plant health and appearance; encourage bushier growth.
Tools
Clean, sharp pruning shears or scissors; disinfect tools between cuts.
Checklist
Disinfect tools; prune dead or damaged growth; shape as needed; remove spent flowers.
Repotting Guide
Best Season
Early spring before new growth begins.
Pot Size
Increase pot size by 1–2 inches in diameter; ensure good drainage holes.
Method
Remove plant gently; trim any circling roots; repot in fresh, well-draining soil with a slightly larger pot.
Suggestions
Repot every 2–3 years or when roots fill the container; beneficial for growth and health.
Checklist
Choose appropriate pot size; prepare fresh soil mix; handle roots carefully; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply at the base; ensure proper drainage; adjust frequency based on season.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone; water early in the day to allow foliage to dry; ensure excess water drains away to prevent waterlogging.
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 to improve drainage; incorporate compost for fertility; ensure soil is loose and airy.
Temperature Stress Management
Signs of Temperature Issues
Yellowing leaves or stunted growth in cold; wilting or leaf scorch in excessive heat.
Cold Stress
Slows growth and may cause leaf discoloration; prolonged cold can lead to root damage or death.
Solution: Move to a sheltered location or indoors during frost; use frost cloth for protection; ensure soil is not waterlogged.
Hot Stress
Leaves may wilt, curl, or scorch; growth may slow due to excessive transpiration.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use diluted fertilizer; apply during growing season only; water before fertilizing; avoid contact with foliage.
Fertilizing Method
Use a balanced liquid fertilizer diluted to half strength every 4–6 weeks during growing season; avoid fertilizing in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats may experience mild gastrointestinal irritation if they consume the roots or seeds of Eryngium amethystinum. The toxicity is not life-threatening but can cause discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of the roots and seeds of Eryngium amethystinum can lead to mild gastrointestinal upset. The plant does not pose a severe threat but can cause discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicEryngium amethystinum contains compounds that can cause mild gastrointestinal distress when ingested. The roots and seeds are the primary toxic parts, containing irritants that may affect the digestive system.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: How do I propagate Eryngium amethystinum?
A: Propagate by seed in spring or by root division in autumn.
Q: Does this plant require full sun?
A: Yes, it thrives in full sun with well-drained soil.
Q: Is Eryngium amethystinum frost-hardy?
A: It is moderately frost-hardy but may require protection in severe winters.
Quick Reference
| Family: | Apiaceae |
| Care: | moderate |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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