How to Grow and Care for Anise Hyssop

Attract bees, butterflies, and hummingbirds with this extended bloomer

Monarch Butterfly (Danaus plexippus) on Anise Hyssop (Agastache foeniculum), which is blossoming in its characteristic blue/light lavender color.

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Contrary to its common name, Anise Hyssop (Agastache foeniculum) is neither anise (Pimpinella anisum) nor hyssop (Hyssopus officinalis). Even so, like hyssop, it is a member of the mint family (Lamiaceae). Leaves give off a subtle scent similar to that of anise, though the chemical anethole in true anise or licorice is not found in high amounts in Anise Hyssop. Instead, Anise Hyssop leaves emit a scent more similar to basil or French tarragon. Unscented flower spikes are typically blue-lavender to purple, depending on the variety, on upright stems adorned with dull green leaves. Each leaf is four inches long with toothed margins akin to the aesthetic of common mint. This clump-forming perennial is native to parts of the Midwest and the Great Plains (Wisconsin to Ontario, west to British Columbia and south to Colorado). Growing in native prairies, dry upland forested areas, plains, and fields, it blooms abundantly from mid to late summer through early fall, attracting bees, butterflies, and hummingbirds. Their extended bloom period makes them good for cut flowers and mass plantings.

Botanical Name Agastache foeniculum
Common Name  Anise Hyssop, Agastache, Licorice Mint, Hummingbird Mint, blue giant hyssop, fragrant giant hyssop, licorice plant, lavender giant hyssop
Plant Type  Native herbaceous perennial
Mature Size  3 - 5 ft. tall, 1 - 3 ft. wide
Sun Exposure  Full sun
Soil Type  Fertile Chalk, Loam, Sand (not heavy clay, which doesn't drain well and causes winter problems)
Soil pH Neutral
Bloom Time  Mid-summer to fall
Flower Color  Pink to creamy white, powder blue to red-violet (most commonly blue to lavender purple)
Hardiness Zones  4-9, USDA
Native Area  North America
Toxicity  Non-toxic, edible

Anise Hyssop Care

Plant Anise Hyssop in spring after the last frost. Establish seedlings any time until early summer. Space 18 to 24 inches apart in borders, wildflower gardens, herb gardens, or butterfly gardens (or as specimens in containers). Reaching 2 to 5 feet tall and 1 to 3 feet wide, these plants serve well in the middle or the back of perennial borders. Pair with companions such as Japanese anemones, other natives such as biennial brown-eyed Susan (Rudbeckia triloba), goldenrods such as Solidago rugosa ‘Fireworks,’ or with fellow herbs like garlic, chives, oregano, and thyme.

Light

Anise Hyssop prefers full sun. It may grow in partial shade but will get lanky without enough sunlight.

Soil

Give plants fertile, well-drained sand, loam, chalk, or clay. Avoid heavy clay, which can cause winter problems. Maintain a pH that is close to neutral and add lime to acidic soils. Dry to medium moisture is best; established plants can usually tolerate dry soils. Winter survival depends on the soil draining well and remaining relatively dry.

Water

Water newly planted Anise Hyssop weekly, if there is no rainfall, for the first four weeks. Water slowly and deeply, welcoming deep, spreading roots. Once plants are established, cease watering. Being drought tolerant, they are very easy to grow and care for.

Fertilizer

Feed each plant about a shovelful of compost in early spring every other year. Sprinkle it around the base and leave a couple of inches of space between the compost and the main stem.

Is Anise Hyssop Toxic?

Anise Hyssop is generally known as non-toxic. It is used in many ways to make the most of its edible properties, licorice aroma, and lasting color.

Uses

Stemming from a long history of medicinal use by Native Americans, Anise Hyssop is a versatile, aromatic, culinary, healing herb. It has many uses in the garden and the kitchen. The flowers' nectar attracts bees, butterflies, and hummingbirds. Meanwhile, birds tend to eat any seeds left on the stalks toward the end of fall. Both flowers and leaves offer an intense licorice scent and taste. Crumble aromatic leaves in salads, use them to make jellies, steep them in herbal tea (as the Cheyenne tribe has done to relieve depression), or incorporate them in potpourris. Sprinkle seeds in cookie, muffin, or biscotti mix; dried leaves can be used as a seed substitute for similar licorice flavor. Fresh flowers make interesting additions to bouquets. Hang these blooming spikes upside down or let them dry naturally on the plant to add to dried floral arrangements.

Varieties

There are many types of Agastache, the genus representing 30 different plants, each with varied flower colors, heights, foliage, aroma, and hardiness. Bloom colors of various hybrid varieties range from pink to creamy white, powder blue to red-violet. Foliage can be dark green to lime green. Here are some of the most popular varieties:

  • ‘Alabaster’ has creamy-white flowers and lighter green foliage. Plants grow about 3 feet tall and are not nearly as bushy as other species.
  • 'Black Adder’ is a hybrid with dark buds and red-violet flowers. It grows less quickly and robustly than other species.
  • ‘Blue Blazes’ is a tall hybrid of A. foeniculum and Agastache ‘Desert Sunrise.’ Hardy to USDA Zone 5, it has pinkish calyxes and lavender purple blooms that seem to glow in the sunlight.
  • 'Blue Fortune' is a sterile hybrid of A. foeniculum and A. rugosa. Especially thick, powder blue flower spikes grow on 3-foot-tall plants. Leaves are large and deep green. Peak bloom is in midsummer. Flowers last a particularly long while because they set no seeds.
  • ‘Blue Fountain’/’Blue Spike’ has clear blue flowers.
  • ‘Golden Jubiliee’ has lasting, powder blue flowers, contrasting pleasingly with its chartreuse foliage. This tough plant thrives even in high heat and humidity.
  • 'Liquorice Blue' has violet-blue flowers with reddish-purple calyxes.
  • ‘Purple Haze’ has narrow flower spikes that are not as attractive to large native bees but may attract smaller pollinators.
  • ‘Red Fortune’ has pink flowers that may not attract as many pollinators as other species.
  • ‘Snow Spike’ (also known as ‘Album’) grows up to three feet tall with white flowers.

Pruning

Overall, Anise Hyssop does not need much attention once it's been established. To encourage blooming and prevent seed heads, deadhead any spent flowers. A light trimming might help keep the plant looking its best, too. Prune in early spring, cutting back up to 1/3 of the woody material, to force a bushier plant. Use sanitized pruning sears or loppers that are very clean and sharp. Make cuts at a slight angle; this will force moisture away from the stem. Every winter in most regions of North America, this perennial will brown and die back for winter. So that fresh new stems may arise more easily in spring, cut back the plant in late winter. Remove any dead plant material just above a promising bud node. Or, leave the plant as is and put a bit more mulch around the root area. If it needs to be rejuvenated, cut Anise Hyssop back more by removing stems within 6 to 12 inches from the ground.

Division

Every 3 to 5 years, dig up the plant and divide it. This will help prevent the center from dying out and rejuvenate the entire plant. Divide in spring. Dig up a part of the clump. Shovel a substantial part of the roots, then replant the division at the same depth as the original planting. Space them 2 feet apart. Water both the original plant and the transplant well.

Propagating

Plants will spread by rhizomes and will easily self-seed if grown in ideal conditions and with proper care. Although it can be propagated by division or stem cuttings, Anise Hyssop can also be grown from seed.

Common Pests & Diseases

Be mindful that crown/root rot may occur in poorly drained soils. Keep an eye out for rust, powdery mildew, and leaf spots. Despite these potential issues, Anise Hyssop is quite hardy, being deer and rabbit resistant and a generally vigorous perennial.