Growing anise hyssop (Agastache foeniculum)
*Agastache foeniculum* -- anise hyssop -- is a North American native perennial that functions simultaneously as a pollinator magnet, culinary herb, and ornamental plant. The leaves have a mild anise-licorice flavor and are used fresh in salads, as a tea, and as a garnish. The dense purple flower.
—- title: "Growing anise hyssop (Agastache foeniculum)" slug: growing-anise-hyssop hub: vegetables category: "Herb guide" description: "How to grow anise hyssop (Agastache foeniculum) for culinary and pollinator use, including zone hardiness, soil, propagation, and harvesting for tea and cooking." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 9 scientific: "Agastache foeniculum" zones_min: 4 zones_max: 9 sun: "full sun to partial shade" —-
Agastache foeniculum — anise hyssop — is a North American native perennial that functions simultaneously as a pollinator magnet, culinary herb, and ornamental plant. The leaves have a mild anise-licorice flavor and are used fresh in salads, as a tea, and as a garnish. The dense purple flower spikes produce nectar attractive to bumblebees, honeybees, and hummingbirds over a bloom period that can stretch 6-8 weeks.
I don't grow anise hyssop at my Long Island plot, though I've seen it doing well in nearby gardens where pollinators congregate in summer. This guide is sourced from Extension and USDA Native Plants resources.
Identification and naming confusion
The "hyssop" name creates confusion. Agastache foeniculum is not related to true hyssop (Hyssopus officinalis) and is a different plant from Korean mint (Agastache rugosa), though both are in the same genus and have similar flavors. Per Missouri Botanical Garden, A. foeniculum is native to central North America and has gray-green, broad-ovate leaves with white undersides. Korean mint (A. rugosa) has narrower leaves with a slightly different flavor profile.
The ornamental Agastache cultivars sold at garden centers ('Ava', 'Blue Boa', 'Golden Jubilee') may or may not be A. foeniculum; many are hybrids. For culinary use, the straight species or named culinary selections are preferred.
USDA hardiness zones
Per NC State Extension, A. foeniculum is hardy in USDA zones 4-9. It is notably short-lived for a perennial — individual plants typically persist 3-5 years before declining. Per Minnesota Extension (UMN), the plant maintains populations through prolific self-seeding, especially in zones 4-7.
Light requirements
Per Missouri Botanical Garden, anise hyssop prefers full sun (6+ hours) but tolerates partial shade (3-5 hours). In partial shade, flowering is reduced and stems become somewhat taller and less sturdy. In the hot, dry conditions of zones 7-9, afternoon shade improves performance.
Sowing and propagation
Per UMN Extension, anise hyssop is easy to grow from seed. Directly sow after the last frost, pressing seeds into the soil surface without covering (light aids germination). Germination occurs in 10-21 days. Thin seedlings to 18-24 inches apart.
For transplant production: sow indoors 6-8 weeks before the last frost date; do not cover seeds; maintain temperature at 65-70°F; germination in 10-14 days under lights.
Division of established clumps in spring (every 2-3 years) also works well. Dig and divide when growth resumes in early spring, replanting divisions 18-24 inches apart.
Watering
Per Missouri Botanical Garden, established anise hyssop is drought tolerant. Water new transplants at 1 inch per week for the first growing season. After establishment, supplemental irrigation is needed only during extended dry periods (2-3 weeks without rain). This is one of the least irrigation-demanding culinary herbs.
Soil requirements
Per NC State Extension, anise hyssop thrives in:
- Well-drained, poor to moderately fertile soil
- pH 6.0-7.0
- Tolerates dry, lean conditions well
Heavily fertilized or rich soils produce lush but often floppy growth that requires staking. This is a prairie-adapted plant; lean, well-drained conditions produce the most compact, self-supporting specimens.
Fertilizing
Per UMN Extension, anise hyssop needs minimal fertilization. In average garden soil, no supplemental fertilizer is needed. In very poor, sandy soil, a single application of balanced fertilizer (10-10-10) at the label rate at planting establishment is sufficient. Annual fertilization is counterproductive.
Harvesting for culinary use
Per Penn State Extension, harvest leaves and flowers for culinary use throughout the growing season. Young leaves have the most delicate anise flavor. Older leaves are more intense and somewhat coarser in texture. Harvest individual leaves or cut stems back by one-third. Flowers are edible and make an attractive garnish for salads and desserts.
For tea: steep 1 tablespoon of fresh leaves (or 1 teaspoon dried) per cup of boiling water for 5-7 minutes.
For drying: cut stems in the morning before flowers fully open. Bundle and hang upside down in a dark, ventilated space. Dried leaves retain flavor for 6-12 months in an airtight container.
Managing self-seeding
Per Missouri Botanical Garden, anise hyssop self-seeds prolifically. One established plant can produce hundreds of seedlings. Deadhead spent flower spikes promptly to limit spread. Leave a few flower heads to go to seed if you want the plant to naturalize — it fills gaps in the border well.
Pests and diseases
Anise hyssop is notably pest-resistant. Per NC State Extension:
Powdery mildew: Most common problem; white coating on leaves in late summer, especially in humid climates or crowded plantings. Improve air circulation; resistant cultivars are available ('Blue Fortune' is reportedly more resistant).
Root rot: In wet, poorly drained soil. Improve drainage before planting.
Aphids: Occasional on new growth. Per UC IPM, control with water spray or insecticidal soap if infestations are heavy.
Deer do not consistently browse anise hyssop in most references, though individual deer pressure varies. Given moderate-to-high deer pressure on Long Island, anise hyssop is worth trying — the aromatic foliage deters most deer.
Common problems
| Symptom | Likely cause | Fix |
|---|---|---|
| Floppy, flopping stems | Rich soil or insufficient sun | Lean soil; full sun site |
| White coating on leaves | Powdery mildew | Improve air circulation; remove badly affected growth |
| Plant declines after year 3 | Short-lived nature | Allow self-seeding; divide clumps every 2-3 years |
| No flowers | Too much shade or excess nitrogen | Full sun; stop fertilizing |
| Seedlings everywhere | Excessive self-seeding | Deadhead before seeds mature |
Frequently asked questions
Is anise hyssop the same as hyssop? Per Missouri Botanical Garden, no. True hyssop (Hyssopus officinalis) is a different genus and species from the Mediterranean, with a more pungent, bitter flavor and different appearance. Anise hyssop (Agastache foeniculum) is a North American native with a sweeter, anise-forward flavor. They are not interchangeable in culinary use.
Can I grow anise hyssop from cuttings? Per UMN Extension, anise hyssop can be propagated from softwood tip cuttings (3-4 inches) taken in early summer. Root in moist perlite under humid conditions. However, seed propagation is easier and more reliable for the straight species.
How does anise hyssop compare to tarragon for anise flavor? Per Penn State Extension, anise hyssop has a milder, sweeter anise flavor compared to French tarragon (Artemisia dracunculus var. sativa), which is more intense and complex. They are complementary rather than interchangeable. Anise hyssop is better for tea and fresh garnish; tarragon is better for cooked savory applications.
Does anise hyssop spread underground? Per NC State Extension, A. foeniculum is clump-forming, not rhizomatous — it does not spread aggressively underground. The spread concern is from self-seeding, which is easily managed by deadheading.
Recommended gear: Best Insecticidal Soap: How Potassium Salts Kill Soft-Bodied Pests — our buyer's guide covering picks for every budget, ranked by Extension publication consensus and personal use.
Sources
- Missouri Botanical Garden — Agastache foeniculum
- NC State Extension — Agastache foeniculum
- UMN Extension — Agastache
- Penn State Extension — Herbs
- UC IPM — Aphids