blue giant hyssop

Agastache foeniculum

Image of giant blue hyssop
Blue hyssop smells like fennel.


Agastache foeniculum, commonly known as anise hyssop or blue giant hyssop, is a species of flowering plant in the mint family (Lamiaceae). It is native to North America, where it can be found from eastern Canada down to the central and eastern United States.

Anise hyssop is a herbaceous perennial plant that can grow up to 3 to 5 feet (90-150 cm) tall, and 1 to 2 feet (30-60 cm) wide. It has an upright, branching habit with square stems that are slightly hairy and green to purple in color. The leaves are opposite, lance-shaped, and toothed, with a distinctive anise scent and flavor when crushed. The foliage is also highly attractive to pollinators, making it a popular choice in pollinator gardens.

In summer, Agastache foeniculum produces long spikes of tubular, two-lipped flowers that are lavender-blue in color and arranged in whorls around the stem. The flowers are highly attractive to bees, butterflies, and hummingbirds, and provide a long-lasting source of nectar.

Overall, Agastache foeniculum is a beautiful and fragrant perennial herb that is highly valued in gardens for its ornamental and ecological value.


blue giant hyssop

USDA Symbol: Common Name: Scientific Name:
AGFO blue giant hyssop Agastache foeniculum

ITIS TSN: 32440

Category: Dicot


Kingdom: Plantae


Super Division: Spermatophyta

Division: Magnoliophyta


Class: Magnoliopsida

SubClass: Asteridae

Order: Lamiales

Family: Lamiaceae

Counties: Ashland, Barron, Bayfield, Burnett, Crawford, Dane, Douglas, Marathon, Marinette, Oneida, Pierce, Polk, Rusk, Sauk, Sawyer, St. Croix, Taylor, Washburn

Natural Community:

Curtis Community: Dry-mesic Prairie, Oak Barrens, Pine Barrens

Coefficient of Conservation: 6

Duration: Growth Habit: Native Status:
Perennial Subshrub, Forb/herb L48(N)CAN(N)

Active Growth Period:

After Harvest Regrowth Rate:


Carbon to Nitrogen Ratio:

Coppice Potential:

Conspicuous Fall Color: Yes

Fire Resistant:

Flower Color: Purple

Conspicuous Flower: Yes

Foliage Color: Green

Foliage Light Porosity Summer:

Foliage Porosity Winter:

Foliage Texture:

Fruit/Seed Color:

Fruit/Seed Conspicuous:

Growth Form:

Growth Rate:

Height at Base Age (Max):

Height at Maturity:

Known Alelopath:

Leaf Retention: No


Low Growing Grass: No


Shape and Orientation:


Height (min): 36

Height (max): 72

Root Type: Rhizome

Leaf Type:

Leaf Arrangement:

Leaf Shape:

Leaf Margin:

Vein Pattern:

Bloom Period: Commercial Availability: Fruit/Seed Abundance:
Summer, Early Summer, Mid Summer, Late Summer Routinely Available
Fruit/Seed Period Begin: Fruit/Seed Period End: Fruit/Seed Persistence:
Propogated by Bare Root: Propogated by Bulbs: Propogated by Container:
Propogated by Corms: Propogated by Cuttings: Propogated by Seed:
Propogated by Sod: Propogated by Sprigs: Propogated by Tubers:
Seeds per Pound: Seed Spread Rate: Seedling Vigor:
Small Grain: Vegetative Spread Rate: Propagation Treatment:
No Moderate Moist Stratification
Days to Stratify: Direct Sowing Time:
60 Early Spring, Spring, Fall, Late Fall

Benefits: Butterflies, Deer Resistant, Hummingbirds, Pollinators

Berry/Nut/Seed Product: Christmas Tree Product: Fodder Product:
No No No
Fuelwood Product: Lumber Product: Naval Store Product:
-- No No
Nursery Stock Product: Palatable Browse Animal: Palatable Graze Animal:
No Low
Palatable Human: Post Product: Protein Potential:
Yes No Low
Pulpwood Product: Veneer Product:
No No
Benefits: Wildlife Food Value: Wildlife Cover Value:
Butterflies, Deer Resistant, Hummingbirds, Pollinators Low


  1. iNaturalist Database – Agastache foeniculum
  2. USDA Plants Database – Agastache foeniculum
  3. WisFlora Database – Agastache foeniculum
  4. Lady Bird Johnson Wildflower Center Database  – Agastache foeniculum

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