Yellow giant hyssop
agastache nepetoides
Also known as: ["Giant yellow hyssop","False giant hyssop"]
Overview
A tall, herbaceous perennial native to North America, known for its spikes of yellow flowers and aromatic foliage.
Benefits & Perks
["long-flowering","deer resistant","wildlife attractant (bees, butterflies, birds)","drought tolerant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Lamiales |
| Family: | Lamiaceae |
| Genus: | Agastache |
| Botanical Name: | Agastache nepetoides |
Plant Characteristics
Basic Information
- Category: Herbs & Weeds
- Suitable Location: border plantings, wildflower gardens, or naturalized areas
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–30–40°C"}
- Hardiness: {"zones":"3–9"}
- Misting: rarely required, only if ambient humidity is very low
- Drainage: Fast-draining to prevent root rot.
- Soil Type: Well-draining, loamy soil with organic matter.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: high
- Pruning Frequency: After flowering or every 2–3 months during the growing season.
- Pruning Intensity: Moderate; remove up to one-third of the plant if overgrown.
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 intense sunlight; protect from harsh afternoon sun in hot climates; ensure adequate airflow 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 during active growth, less frequently in winter
Water thoroughly but infrequently; ensure soil dries slightly between waterings; avoid waterlogging.
Soil
well-drained, loamy soil with moderate organic matter
pH: Slightly acidic to neutral (pH 6.0–7.0).
Avoid heavy clay soils; ensure soil is loose and crumbly; test pH annually.
Temperature
Prefers cool to moderate temperatures (60–75°F or 15–24°C). Tolerates cold but may struggle in prolonged heat.
Avoid sudden temperature fluctuations; protect from cold drafts; ensure good air circulation in hot weather.
Fertilizing
every 4–6 weeks during spring and summer
Fertilize sparingly; apply before new growth emerges; stop fertilizing in late summer to avoid tender growth.
Propagation
Methods
Stem cuttings or division in spring.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Keep moist and warm.
Best Time: Early spring or late summer when the plant is actively growing.
Environment
Warm, humid conditions with indirect light; maintain consistent moisture.
Medium
Well-draining potting mix with perlite or sand.
Hormone
Optional, but rooting hormone can improve success rates.
Timeline
Roots develop in 3–4 weeks; establish in new pots within 2–3 months.
Tools Needed
Pruners, rooting hormone, small pots, well-draining medium.
Quick Tips
Use healthy, non-flowering stems; maintain humidity with a plastic cover; avoid direct sunlight.
Pruning & Repotting
Pruning Guide
Method
Deadhead spent flowers; trim leggy stems; cut back in late fall after frost.
Pruning Plan
Prune to maintain shape, encourage bushiness, and remove spent flowers to prolong blooming.
Tools
Pruning shears, bypass cutters, gloves.
Checklist
Clean tools; prune dead or damaged stems; remove spent flowers; shape as needed.
Repotting Guide
Best Season
Early spring before new growth begins.
Pot Size
Increase pot size by 2–3 inches in diameter.
Method
Gently remove plant; trim roots if necessary; replant in fresh, well-draining soil with added perlite.
Suggestions
Repot every 2–3 years or when roots fill the container.
Checklist
Choose appropriate pot; prepare fresh soil mix; 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, 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; incorporate perlite or sand for drainage; ensure good aeration.
Temperature Stress Management
Signs of Temperature Issues
Wilting, leaf scorch, stunted growth, or premature flowering in excessive heat; leaf drop or dieback in cold stress.
Cold Stress
Slows growth, may cause root damage in poorly drained soil, and can lead to winter dieback.
Solution: Mulch heavily in winter; plant in well-drained soil; protect from frost with row covers or cloches.
Hot Stress
Leaves may wilt, flowers fade quickly, and growth may become leggy due to heat stress.
Solution: Provide afternoon shade; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; avoid late-season feeding.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring. Avoid over-fertilizing, as Agastache nepetoides prefers lean soil.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicAgastache nepetoides is not considered toxic to cats. The plant is generally safe for feline consumption, though excessive intake may lead to mild digestive discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Non-toxicAgastache nepetoides is not considered toxic to dogs. The plant is generally safe for canine consumption, though large quantities may cause mild gastrointestinal upset.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Non-toxicAgastache nepetoides, commonly known as yellow giant hyssop, is not considered toxic to humans. It is a member of the mint family and is generally safe for consumption in culinary and medicinal applications.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Agastache nepetoides edible?
A: The leaves and flowers are edible and can be used in teas or as garnishes.
Q: Does this plant attract pollinators?
A: Yes, it is highly attractive to bees, butterflies, and hummingbirds.
Q: How tall does Yellow giant hyssop grow?
A: It typically reaches 4–6 feet in height.
Quick Reference
| Family: | Lamiaceae |
| Care: | easy |
| Light: | full sun to partial shade |
| Water: | every 7–10 days during activ |
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