Alpine Sea Holly
eryngium alpinum
Also known as: ["Alpine Eryngo","Mountain Sea Holly"]
Overview
A striking perennial herbaceous plant with spiky, silvery-blue foliage and globe-shaped flowers, native to alpine regions.
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 alpinum |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: border plantings or rock gardens in temperate climates
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–15–35°C"}
- Hardiness: {"zones":"4–8"}
- Misting: rarely required
- Drainage: Well-draining to fast-draining.
- Soil Type: Rich, loamy soil with good drainage; benefits from added organic matter.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: After flowering; lightly prune throughout the growing season to remove dead or damaged foliage.
- Pruning Intensity: Light to moderate; avoid heavy pruning unless dividing the plant.
Care Details
Ideal Sunlight Coverage:
Full sun (6–8 hours of direct sunlight daily); tolerates partial shade but may produce fewer flowers.
Sunlight Tolerance Tips:
Acclimate plants gradually to full sun if moved from shade; protect from intense midday sun in hot climates; ensure good air circulation to prevent fungal issues.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
full sun to partial shade
Rotate plants for even growth; use shade cloth in extreme heat; avoid placing in drafty areas.
Watering
every 7–10 days during active growth, reduce in winter
Water thoroughly but allow soil to dry slightly between waterings; avoid waterlogging, especially in winter.
Soil
well-drained, loamy soil with moderate fertility
pH: Slightly acidic to neutral (pH 6.0–7.0).
Ensure soil is not compacted; avoid heavy clay soils; mulch to retain moisture and suppress weeds.
Temperature
Hardy in USDA zones 4–9; prefers cool summers and tolerates cold winters. Ideal range: 60–75°F (15–24°C) during growth.
Avoid sudden temperature fluctuations; protect from late frosts; ensure good air circulation in warm weather.
Fertilizing
every 4–6 weeks during spring and summer
Fertilize sparingly; apply before new growth emerges; stop fertilizing in late summer.
Propagation
Methods
Division or root cuttings in early spring.
Step-by-Step Propagation Guide
- Divide clumps into sections with healthy roots.
- Plant cuttings horizontally just below the soil surface.
- Keep moist and warm.
Best Time: Early spring before active growth begins.
Environment
Warm, humid conditions with indirect light; protect from direct sun until established.
Medium
Well-draining potting mix with added perlite or sand.
Hormone
Optional, but rooting hormone can improve success rates for root cuttings.
Timeline
Root cuttings may take 4–6 weeks to root; divisions establish quickly in the growing season.
Tools Needed
Sharp knife, pruning shears, rooting hormone (optional), pots, well-draining medium.
Quick Tips
Divide every 3–4 years to maintain vigor; use clean tools to prevent disease; keep soil consistently moist but not waterlogged.
Pruning & Repotting
Pruning Guide
Method
Deadhead flowers by cutting stalks at the base; trim foliage as needed with clean cuts.
Pruning Plan
Remove spent flower stalks to encourage reblooming; cut back foliage in late autumn or early spring to maintain shape.
Tools
Pruning shears, gloves, clean knife.
Checklist
Use clean tools; cut spent flowers; remove damaged leaves; shape as needed.
Repotting Guide
Best Season
Early spring before new growth starts.
Pot Size
One size larger pot (e.g., +2–3 inches in diameter).
Method
Gently remove the plant; trim any dead roots; repot in fresh, well-draining soil with a slightly larger pot.
Suggestions
Repot every 2–3 years or when the plant becomes root-bound; beneficial for container-grown plants.
Checklist
Choose appropriate pot size; use fresh soil mix; trim roots if necessary; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure good drainage; avoid overhead watering.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone. Water early in the day to minimize evaporation and allow foliage to dry.
Watering Schedule Tips
Water deeply once a week during active growth, reducing frequency in winter. Adjust based on rainfall and soil moisture retention.
Soil Improvement
Add compost or well-rotted manure to enhance fertility; incorporate sand or perlite for drainage.
Temperature Stress Management
Signs of Temperature Issues
Chlorosis or wilting in excessive heat; stunted growth or leaf drop in prolonged cold or frost.
Cold Stress
Plants may become dormant in winter but can suffer root damage if soil is waterlogged and frozen.
Solution: Ensure well-drained soil; apply a thick layer of mulch before winter; protect from harsh winds.
Hot Stress
Leaves may scorch or wilt in intense heat, especially if soil is dry.
Solution: Provide afternoon shade in hot climates; water deeply and mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; avoid late-season feeding; water after application.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring; avoid over-fertilizing, as Eryngium alpinum is not heavy feeder.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicEryngium alpinum is not toxic to cats. No toxic effects have been documented in felines after ingestion of this plant.
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Non-toxicEryngium alpinum is not toxic to dogs. There are no known adverse effects associated with ingestion of this plant by canines.
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Non-toxicEryngium alpinum, commonly known as Alpine Sea Holly, is not considered toxic to humans. It has no known toxic compounds or physiological effects when ingested in typical amounts.
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: How do I propagate Alpine Sea Holly?
A: It can be propagated by division in early spring or by seeds sown in late summer.
Q: Does Alpine Sea Holly attract pollinators?
A: Yes, its flowers are attractive to bees, butterflies, and other pollinators.
Q: What are the ideal growing conditions for this plant?
A: It thrives in full sun and well-drained, alkaline to neutral soil, making it suitable for rock gardens and dry borders.
Quick Reference
| Family: | Apiaceae |
| Care: | moderate |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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