South Dakota Native Plant Research
Agastache foeniculum

Scientific Name

Agastache foeniculum


Download Seed: The nutlets are 1.3 to 1.5 mm long. (428 KB)

Download Seedling: Three month old seedling of lavender hyssop. (115 KB)

Download Vegetative: The leaf blades are 4-9 cm long and 2-2.5 cm wide. (527 KB)

Download Flowering: The flower spikes can be 4-12 cm long. (494 KB)

Download Fruiting: Lavender hyssop produces fruit in late summer. (861 KB)

Download Plants (999 KB)

Family Name


Common Name

Lavender hyssop, Blue Giant Hyssop

Native American Name

Lakota: wahpe' yata' pi


Agastache foeniculum is a perennial rhizomatous forb, which grows 0.6 m to 1 m in height. The stems are square with opposite ovate to broad to lanceolate leaves, greenish above and whitish underneath due to a fine, appressed pubescents. When crushed the leaves smell of anise. Flowers open in July and August and are arranged in a terminal spike-like raceme. The tubular calyx is 5 toothed 5-7 mm long and lavender toward the tips. The corolla is 2-lipped 7-10 mm long and lavender to bluish-purple in color. Stamens 4 and exerted from corolla. Pistil with 2 carpels with a 2-part style. Fruit are 4 nutlets. This species is commonly found in upland woods and prairies.

Additional Notes: The leaves and flowers make a very pleasant tea. The flowers attract honeybees, bumble bees and butterflies. The mature fruit is a staple for birds such as the gold finches

Additional Notes

wahpe' yata'pi means leaf that is chewed

Horticulture Notes

Seed Collection: Collect seed in September
Germination: Fall sow or stratification
Vegetative Propagation: Easily planted by division of rootstock cuttings
Soils: Sandy (well drained)
Water: Moist
Notes: The seeds smell like licorice

Agastache foeniculum