Notice: We do not accept seeds that were given before 2024 as they had hybridized with Korean mint.
Plant Names
Agastache foeniculum
Blue Giant-hyssop
Agastache fenouil
Synonyms
anise hyssop
anise-mint
fennel giant hyssop
fragrant giant-hyssop
giant-hyssop
lavender giant-hyssop
licorice-mint
Plant Characteristics
Bloom Colour: Purple
Bloom Period: Jun - Sep
Max Height: 3.0 feet
Max Width: 1.5 feet (spreads by rhizome)
Light Condition:
More than 6 hours of direct sun a day
More than 2 or 3 hours but less than 6 hours of direct sun a day
Soil conditions:
Tolerates medium soil condition
More than 6 hours of direct sun a day
More than 2 or 3 hours but less than 6 hours of direct sun a day
Tolerates medium soil condition
Lifespan:
Perennial
plants that will come back year after year
Gardener Experience:
Spreads by rhizome
Easy to germinate
Self-seeding
Spreads by rhizome
Easy to germinate
Self-seeding
Landscape Uses:
Suitable for rain gardens
Suitable for container garden
Suitable for school gardens
Tolerates boulevard garden conditions
Suitable for rain gardens
Suitable for container garden
Suitable for school gardens
Tolerates boulevard garden conditions
Ecological Benefits:
Supports hummingbirds
Butterfly host
Supports hummingbirds
Butterfly host
Tolerates:
Tolerates drought conditions
Tolerates salt conditions
Deer resistant
Rabbit resistant
Tolerates limestone conditions
Tolerates transplantation
Tolerates drought conditions
Tolerates salt conditions
Deer resistant
Rabbit resistant
Tolerates limestone conditions
Tolerates transplantation
Special Features and Considerations:
Seed and plant distribution status
No seeds available for this plant.
We currently accept seeds for this plant
Fun Facts
Blue giant hyssop is a native perennial wildflower found in prairies, open woodlands, and meadow habitats. It produces tall spikes of lavender-blue flowers with aromatic leaves that smell like anise or licorice. It is a favourite plant for pollinator gardens.
Excellent for pollinator gardens, herb gardens, and sunny borders.
Spreads by seed but is not invasive.
Drought tolerant once established.
Low maintenance.
May self-seed in favourable conditions.
One of the easiest native plants for beginners.
Deadheading encourages longer flowering but leaving seed heads helps birds.
Avoid overly rich soils, which can cause floppy growth.
Great companion plant for prairie flowers.
Excellent for pollinator gardens, herb gardens, and sunny borders.
Spreads by seed but is not invasive.
Drought tolerant once established.
Low maintenance.
May self-seed in favourable conditions.
One of the easiest native plants for beginners.
Deadheading encourages longer flowering but leaving seed heads helps birds.
Avoid overly rich soils, which can cause floppy growth.
Great companion plant for prairie flowers.
Plant Location
Distribution according to VASCAN
Ephemeral
Native
Introduced
Excluded
Extirpated
Doubtful
Absent
Canadensis
Thrives in Ecozones
- Taiga Plains
- Boreal Plains
- Montane Cordillera
- Prairies
- Mixed Wood Plains
Ecological Benefits
Butterflies Supported by Agastache foeniculum
No butterfly data available for this plant.
Specialized Bees Supported by Agastache foeniculum
No bee data available for this plant.
Complementary Plants
- Andropogon gerardi
Big Bluestem
Barbon de Gérard - Heliopsis helianthoides
False Sunflower
Héliopsis faux-hélianthe - Solidago juncea
Early Goldenrod
Verge d'or jonciforme - Symphyotrichum oolentangiense
Sky Blue Aster
Aster azuré - Veronicastrum virginicum
Culver's Root
Véronique de Virginie
Substitute For Non-Native Plants
- Linum usitatissimum (Common Flax)
- Perovskia Atriplicifolia (Russian Sage)
- Lupinus (Non-Native Lupins)
- Ajuga reptans (Bugleweed)
- Buddleia (Butterfly Bush)
- Delphinium (Delphinium)
- Salvia (Non-Native Sage)
- Lavandula (Lavender)
Sowing Information
Download Seed Envelope Labels (PDF)
- Sowing depth: Surface sow
- Sow by March
- Stratification duration: 30 days
- Self-seeding
Harvesting and Seed Sharing
- Harvest start month: October
- Harvesting indicator:
- Pods are brown and crisp and starting to open
- Seeds are dark and tiny stem attaching to the main stem is brown
- Seeds easily fall off pod when shaken
- Little stem connecting the pod to the main stem is brown (not green)
- Harvesting:
- Put pods in food processor or blender and blend seeds, and strain seeds using a strainer
- Seed viability test:
- No test needed before donating
- Packaging measure: Half of one, 1/32 teaspoon
- Seed storage:
- Air dry in paper bag or open container, for a few days until crisp
- Shake seeds to move them once in a while to prevent molding
- Cultivar: Yes, do not donate unless you know source, and there are no known cultivars in your garden or at proximity
- Harvesting notes: Please only donate seeds from the Seed Library that you received after 2024, as before they were cross-pollinatoed with Korean mint. Thanks!
- Harvesting video: Watch here
Toxicity Notes
Can cause cats indigestion.