How To Care For Anise Hyssop (Agastache Foeniculum)

Anise Hyssop aka Agastache Foeniculum [Ah-GAH-sta-kee, Fin-ICK-yoo-lum] is a perennial plant species in the mint family Lamiaceae that includes horsemint, Lamium, and meadow sage

It is native to northern and north-central North America, particularly the Great Plains, and is also found in Canada.

Flowers of the Anise Hyssop plant (Agastache Foeniculum)

The common names of Agastache Anethiodora (syn.) include:

  • Anise Hyssop
  • Lavender Hyssop
  • Blue Giant Hyssop
  • Giant Hyssop
  • Lavender Giant Hyssop
  • Fragrant Giant Hyssop

Anise Hyssop Agastache Foeniculum Care

Size & Growth

This clump-forming, upright plant usually grows 3’ to 5’ feet high and 1’ to 3’ feet wide. 

Just like other species in the mint family, Anise Hyssop also has square stems. 

It has alternate ovate-shaped leaves, which grow 4” inches long. 

The green leaves have a whitish tint towards their underside and toothed margins.

Its fragrant foliage has an anise (licorice-like) scent. 

Agastache spreads through its rhizomes and self-seeds in ideal growing conditions.

Flowering and Fragrance

The Anise Hyssop produces cylindrical erect flower spikes, which continues to bloom throughout the fall season. 

The small purple flowers occur in showy, dense verticillasters, or false whorls packed tightly together.

The bloom color varies from lavender to purple, and the bloom time of this plant is mid-to-late summer.

Light & Temperature

This plant performs best in full sun but also thrives in part shade. 

Place it in a location where it receives direct sunlight for a few hours during the day.

Agastache are hardy to USDA Hardiness Zones 3 through 8.

Watering and Feeding

The water needs of this plant are low. 

It requires little watering once it is planted, just enough to moisten the roots. If the soil is damp, do not water. 

Prolonged exposure to soggy soil will result in mildew and mold.

Feed it with all-purpose, balanced fertilizer annually during the early spring season. 

Follow the directions on the package, and make sure to deeply water after fertilizing to avoid root burn.

Soil & Transplanting

The Anise Hyssop performs best in moist soils, but it requires a proper drainage system. 

Once established, it tolerates dry soils. 

Therefore, be sure to keep a watch on the soil moisture.

The seedlings are easily transplanted during their initial growth period. 

Keep in mind it is normal for them to slightly wilt once they are moved. 

Make sure to provide ideal growing conditions, and they will quickly recover in the next few days.

Grooming and Maintenance

The Agastache hyssop is easy to grow and doesn’t require much maintenance. 

Deadhead spent flowers as it will encourage additional bloom.

The ideal time of harvesting the foliage to dry is once the flowers have fully bloomed. 

It is when the leaves have their highest oil content and the best time to harvest to obtain the oil, for later use as needed.

How To Propagate Agastache Plants

Propagation is done through seeds, divisions, and cuttings.

  • Let the flower spikes dry on the plant and bag them to collect the ripening seeds. 
  • After the seed collection, sow them in a greenhouse during the spring season. 
  • Slightly cover the seeds and let them germinate for one to three months. 
  • Transplant them in individual pots once they become big enough to handle. 
  • Be sure to grow them inside the greenhouse for their first year.

Propagating by division should be done in spring. 

  • If you are taking a large division, plant them directly in their permanent positions.
  • The basal cuttings should also be done during the spring season. 
  • Plant the young shoots once they grow 4” to 6” inches long. 
  • Place them under a shaded area inside the greenhouse. 
  • Within three weeks, it will start establishing roots. 
  • Plant them out in the summer season or the next spring season.

Agastache Hyssop Pest or Diseases

The Fragrant Giant Hyssop doesn’t experience any severe disease or insect problems. 

However, poorly drained soils may cause crown or root rotting. 

Be on a lookout for leaf spots, powdery mildew, and rust, particularly in humid climates.

This plant is deer resistant, but rabbits like to nibble on the foliage. 

It attracts various pollinators, including hummingbirds, honeybees, bumblebees, night flying moths, carpenter bees, and butterflies.

Uses For Anise Hyssop Plants

This plant works well in wildflower gardens, borders, herb gardens, meadows, butterfly gardens, forested areas, prairies, and dry fields. 

Its aromatic leaves are used in herbal teas, flavored jellies, and also eaten fresh in salads.

The seeds of this plant are also added in muffins and cookies, dried leaves make excellent potpourri, and the flower spikes look attractive in dried arrangements and cut flowers. 

The Native Americans used this plant medicinally for treating diarrhea, wounds, fever, and coughs.