Anise hyssop (Agastache foeniculum)

Overview

Anise hyssop (Agastache foeniculum) is a beloved vertical accent in the garden, renowned for its fragrant, edible foliage and extended summer color display. This upright, clump-forming perennial belongs to the mint family and brings robust texture and excellent pollinator support wherever it is planted. Its key feature is the sweet, anise-scented leaves, which are fantastic harvested for teas or culinary uses.

This variety thrives across wide environmental conditions, preferring full sun but tolerating light shade, making it surprisingly versatile. While it performs well in average moisture, Agastache foeniculum demonstrates excellent drought tolerance once established, anchoring it as a reliable choice for low-maintenance landscapes. Gardeners appreciate the continuous flowering from early summer well into autumn.

The lavender to purple flower spikes of Anise hyssop are magnets for bees and butterflies, significantly boosting the local ecosystem. Furthermore, dried flower heads provide everlasting interest and texture. Whether used in herb gardens, borders, or naturalized settings, Agastache foeniculum offers significant aesthetic and functional benefits to the gardener.

Fast Facts

• Plant Family: Lamiaceae
• Plant Type: Herbaceous perennial
• Native Range: Northern North America
• Hardiness Zones: USDA Zones 4-8
• Size at Maturity:
  • Height: 2-4 ft
  • Spread: 1.5-3 ft
• Bloom Time: June to September
• Bloom Description: Lavender to purple
• Sun Exposure: Full sun to part shade
• Water Needs: Dry to medium
• Maintenance Level: Medium

How to Grow

Plant Anise hyssop in the spring after the danger of frost has passed, or in early autumn. The best location features full sun, which encourages the densest, most prolific flowering. While Agastache foeniculum handles moist soils, excellent drainage is crucial to prevent root issues. Incorporate organic matter lightly, but avoid heavy enrichment, as this plant naturally prefers average conditions.

Ongoing care focuses primarily on moisture management until the roots establish. Water regularly during the first season to build resilience. Once mature, this plant tolerates dry spells due to its inherent drought tolerance. Fertilizing is rarely necessary; over-fertilization can lead to floppier stems rather than robust flowering.

Deadheading spent flower spikes is highly recommended. This simple practice encourages the plant to produce new flushes of bloom throughout the season, extending your floral display well beyond mid-summer. Be aware that Anise hyssop spreads gently via rhizomes and may self-seed where conditions are ideal. In spring, cut back old, dead stems close to the ground.

Landscape Uses

The upright, airy habit of Agastache foeniculum makes it an excellent choice for the middle or back of perennial borders, providing vertical contrast against lower-growing companions. Its tolerance for drier soils integrates beautifully into wildflower meadows or naturalized areas where less demanding plants are favored. Consider planting large drifts to maximize the impact of the lavender flower spikes.

For herb gardens, the fragrant leaves of Anise hyssop are indispensable for teas and infusions, positioning it perfectly alongside culinary sage or thyme. In pollinator-focused plantings, pair it with coneflowers (Echinacea) or blazing star (Liatris) which share similar sun and water requirements. Flowers are equally effective in providing texture for fresh-cut bouquets or dried floral arrangements.

Standout Features

Flower Qualities

• Showy
• Good Cut
• Good Dried

Noteworthy Characteristics

Agastache foeniculum, commonly known as anise hyssop, is an upright, clump-forming perennial of the mint family that is native to parts of the upper Midwest and Great Plains. It is noted for its mid- to late summer bloom of lavender to purple flowers in terminal spikes and its anise-scented foliage. The flowers are highly attractive to bees and butterflies, and the aromatic leaves can be easily harvested for teas.

Tolerances

• Deer
• Drought
• Dry Soil

Potential Problems

The primary cultural issue for Agastache foeniculum relates to drainage. Crown or root rot is a significant risk if the plant sits in heavy, poorly drained soils, especially through winter. To mitigate this, ensure planting beds are amended for superior drainage or select a slightly raised location.

Fungal diseases, including rust, powdery mildew, and various leaf spots, can occasionally appear, particularly in humid conditions or when air circulation is poor. Good garden hygiene, spacing plants adequately to allow airflow, and watering the soil—not the foliage—will help suppress these issues. Good cultural practice keeps the Anise hyssop healthy and blooming profusely.

Frequently Asked Questions

What hardiness zones is Anise hyssop suitable for?

This perennial is reliably hardy in USDA Zones 4 through 8.

How large does Agastache foeniculum grow?

This plant typically reaches a mature height between 2 to 4 feet tall, with a spread ranging from 1.5 to 3 feet wide.

When does Anise hyssop bloom?

You can expect blooms from June through September, featuring attractive spikes of lavender to purple flowers.

What sun exposure does Agastache foeniculum need?

For the best performance, the plant requires a location receiving full sun, though it can tolerate areas of part shade.

Conclusion

The dependable bloom time, exceptional drought tolerance, and highly aromatic foliage make Anise hyssop a standout choice for almost any sunny garden space. Integrating Agastache foeniculum ensures consistent pollinator activity throughout the warm months. Before planting, confirm your local hardiness zone aligns with Zones 4-8 for best long-term success.

Wildlife Benefits

The dense flower spikes of Agastache foeniculum are renowned as a premier nectar source for native bees and honeybees. Planting this herb provides crucial mid-to-late summer forage when many early-season blossoms have faded. The color and structure of the flowers also draw in hummingbirds and butterflies, transforming your perennial border into an active wildlife sanctuary.

Companion Planting

When planning garden layouts, consider companions that share the preference for full sun and gritty, dry-to-medium soil, mirroring the needs of Agastache foeniculum. Excellent partners include plants that bloom at slightly different times or offer contrasting foliage color, such as Russian Sage (Perovskia atriplicifolia) or ornamental grasses like Blue Fescue. Avoiding overly moisture-loving plants near established Anise hyssop prevents unnecessary competition or soil saturation issues.