Giant Yarrow
achillea macrophylla
Also known as: ["Great Yarrow","Large-leaved Yarrow"]
Overview
A herbaceous perennial with large, fern-like leaves and flat clusters of small, daisy-like flowers, typically white or pale pink.
Benefits & Perks
["long-flowering","deer resistant","wildlife attractant (bees, butterflies, birds)","drought tolerant","aesthetic foliage"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Achillea |
| Botanical Name: | Achillea macrophylla |
Plant Characteristics
Basic Information
- Category: Flowers
- Suitable Location: border plantings, rock gardens, or cottage garden settings
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"5–35°C"}
- Hardiness: {"zones":"4–8"}
- Misting: rarely required, only if grown in very dry indoor conditions
- Drainage: Fast-draining; poor drainage can lead to root rot.
- Soil Type: Well-draining, loamy soil with added organic matter; tolerates poor soil but benefits from compost.
Maintenance Level
- Maintenance Level: low
- Toughness Level: high
- Pruning Frequency: Deadhead flowers throughout the growing season; cut back foliage in late fall or early spring.
- Pruning Intensity: Light to moderate; avoid heavy pruning during active flowering unless necessary.
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
easymoderate
Sunlight
full sun to partial shade
Rotate plants for even light exposure; use shade cloth in extreme heat; avoid placing in drafty areas.
Watering
every 7–10 days, allowing soil to dry slightly between waterings
Water at the base to avoid foliage, ensure soil dries slightly between waterings, and avoid overwatering which can cause root rot.
Soil
well-draining, loamy soil with moderate organic content
pH: Slightly acidic to neutral (pH 6.0–7.0).
Avoid heavy clay soils; amend with organic matter; ensure pots have drainage holes.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C); tolerates cold but may struggle in prolonged heat.
Monitor temperature extremes; adjust watering; protect from frost or heatwaves.
Fertilizing
every 4–6 weeks during active growth with a balanced, water-soluble fertilizer
Fertilize sparingly; apply before new growth emerges; stop fertilizing in late summer to avoid tender growth.
Propagation
Methods
Stem cuttings or division; division is often more reliable for mature plants.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone (optional).
- Plant in medium.
- Maintain humidity.
Best Time: Early spring or fall when the plant is not in active bloom.
Environment
Warm, humid environment with indirect light; keep soil consistently moist but not waterlogged.
Medium
Well-draining potting mix with perlite or sand; can also root in water initially.
Hormone
Rooting hormone can be used but is not always necessary for Achillea.
Timeline
Stem cuttings may root in 2–4 weeks; division can be done anytime the plant is dormant or semi-dormant.
Tools Needed
Pruning shears, rooting hormone, pots, well-draining medium.
Quick Tips
Take cuttings from healthy, non-flowering stems; keep cuttings out of direct sun; maintain consistent moisture.
Pruning & Repotting
Pruning Guide
Method
Use clean, sharp tools; cut spent flower stems just above a leaf node or lateral bud.
Pruning Plan
Remove spent flowers to encourage reblooming; cut back foliage in fall to tidy appearance and reduce disease risk.
Tools
Pruning shears, gloves, disinfectant for tools.
Checklist
Clean tools; deadhead regularly; cut back in fall or spring; dispose of diseased foliage.
Repotting Guide
Best Season
Early spring before new growth begins; avoid repotting during flowering or extreme temperatures.
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 dead or crowded 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; division at repotting can rejuvenate the plant.
Checklist
Choose appropriate pot size; prepare fresh soil mix; trim roots if needed; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; allow drainage; avoid wetting foliage.
How to Apply Water Properly
Water thoroughly until it drains from the bottom, ensuring the root zone is moistened but not waterlogged; water early in the morning to minimize evaporation.
Watering Schedule Tips
Water deeply once a week during active growth, reducing frequency in winter; adjust based on rainfall and soil moisture.
Soil Improvement
Add perlite or sand for drainage; incorporate compost for fertility; ensure good aeration.
Temperature Stress Management
Signs of Temperature Issues
Wilting, yellowing leaves, stunted growth, or flower bud drop in extreme heat; leaf discoloration or dieback in cold stress.
Cold Stress
Low temperatures can slow growth and cause leaf damage or dieback, especially if combined with wet soil.
Solution: Provide winter mulch for insulation; avoid overwatering in cold weather; move potted plants to a sheltered location.
Hot Stress
Excessive heat can lead to wilting, leaf scorch, and reduced flowering; may require more frequent watering.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; avoid over-fertilization.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring; avoid high-nitrogen formulas which can reduce flowering.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicAchillea macrophylla is not considered toxic to cats. The plant is generally safe for feline consumption, though excessive intake may cause mild gastrointestinal discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Non-toxicAchillea macrophylla is not considered toxic to dogs. The plant is generally safe for canine consumption, though excessive intake may lead to mild gastrointestinal upset.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Non-toxicAchillea macrophylla is generally considered non-toxic to humans. However, ingestion in large quantities may cause mild gastrointestinal discomfort due to its essential oils.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten in large quantities
Frequently Asked Questions
Q: How do I propagate Achillea macrophylla?
A: It can be propagated by division in early spring or by seed sown in early autumn.
Q: Does Achillea macrophylla attract pollinators?
A: Yes, it is highly attractive to bees, butterflies, and other pollinators.
Q: What are the ideal growing conditions for Achillea macrophylla?
A: It thrives in full sun and well-drained soil, tolerating drought once established.
Quick Reference
| Family: | Asteraceae |
| Care: | easy |
| Light: | full sun to partial shade |
| Water: | every 7–10 days, allowing so |
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