South Dakota Native Plant Research
Lamiaceae: Agastache foeniculum

Lamiaceae: 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 herb, which grows 0.6 m to 1 m in height. The stems are square with opposite ovate to broad to lanceolate simple leaves, greenish above and whitish underneath due to fine, appressed hairs the leaf margins are finely toothed. 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. Lavender hyssop blooms from June through September. This species is commonly found in upland woods and prairies in both eastern and western South Dakota.

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 finch.

wahpe' yata'pi means leaf that is chewed

Horticulture Notes

Seed Collection: Collect seed in September
Germination: Fall sow or 60 day cold stratification.
Vegetative Propagation: Easily planted by division of rootstock cuttings.
Soils: Sandy (well drained)
Light: Full sun to partial shade.
Water: Moist to medium dry conditions.
Notes: The seeds smell like licorice

Lamiaceae: Agastache foeniculum