Giant hyssop (Agastache rugosa 'Honey Bee Blue')

Overview

Agastache rugosa ‘Honey Bee Blue’, commonly known as Giant hyssop, is a highly valued herbaceous perennial prized for its intense, long-lasting blue flowers and aromatic foliage. This cultivar provides excellent vertical interest, reaching heights up to three feet with rigid, upright stems that hold the blooms reliably through the summer months. Gardeners appreciate this plant for its low-maintenance nature and significant appeal to vital pollinators.

The specific variety, Agastache rugosa ‘Honey Bee Blue’, distinguishes itself with deep blue flowers contrasting nicely with aromatic gray-green leaves. As part of the Mint family, it offers fragrance when leaves are crushed, making it a versatile addition to both ornamental borders and herb gardens. It ensures reliable color from mid-summer well into early fall.

Cultivating Giant hyssop is straightforward, requiring excellent drainage to ensure winter survival outside of ideal conditions. Once established, this plant tolerates both heat and periods of dryness, offering consistent performance with minimal fuss. Its ability to attract hummingbirds, bees, and butterflies reinforces its role as an essential component in pollinator-friendly landscapes.

Fast Facts

• Plant Family: Lamiaceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 5-8
• Size at Maturity:
  • Height: 2-3 ft
  • Spread: 1.5-2 ft
• Bloom Time: July to September
• Bloom Description: Blue
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Planting Agastache rugosa ‘Honey Bee Blue’ is best achieved in spring after the danger of frost has passed, positioning it in locations receiving full sun, though it tolerates light afternoon shade. Excellent soil drainage is absolutely critical; this plant performs poorly and may fail to survive winter in heavy clay soils that remain soggy. Amend heavy soil well with grit or compost to improve structure.

Water needs are medium, meaning the soil should be kept consistently moist, especially while the plant is establishing its root system. Once established, this Giant hyssop tolerates mild drought conditions due to its adaptability. Minimal fertilization is typically needed; over-fertilizing can lead to weaker stems.

Maintenance is low. Deadheading spent flower spikes encourages a fresh flush of the intense blue blooms throughout the season. At the end of the growing season, leave the dead stems standing to provide winter protection for the crown. Cut back the dead material only in late winter or early spring before new growth begins.

To further protect plantings, especially in marginal zones, apply a gravelly or sandy mulch around the base; this helps minimize rot potential over winter. If container growing, plants benefit from a spring pinching back of foliage tips to manage mature height.

Landscape Uses

Agastache rugosa ‘Honey Bee Blue’ excels when used where its vertical interest and long bloom period can be maximized. It works beautifully along borders or integrated into mixed perennial beds, contrasting nicely with finer-textured or lower-growing companions. Its hardiness as an herb also makes it a compelling choice for dedicated herb gardens.

For wildlife enthusiasts, incorporating this Giant hyssop is recommended for butterfly gardens, as the tubular flowers are magnets for pollinators. Furthermore, it performs adequately when grown in containers, allowing gardeners with limited space to enjoy the fragrant foliage and flowers of Agastache rugosa ‘Honey Bee Blue’.

Standout Features

Flower Qualities

• Showy
• Fragrant

Noteworthy Characteristics

Agastache rugosa, commonly called purple giant hyssop, is an upright, clump-forming, herbaceous perennial that typically grows to 2-3’ tall. Leaves and flowers are aromatic. Fragrant, tubular, 2-lipped, violet-pink flowers bloom summer-to-fall in whorls on erect, terminal, salvia-like spikes atop strong, rigid stems. The variety ‘Honey Bee Blue’ features intense blue flowers and aromatic gray-green foliage, providing a long summer bloom period attractive to bees and hummingbirds.

Tolerances

• Deer

Potential Problems

Serious insect or disease problems are rare for Agastache rugosa ‘Honey Bee Blue’. The primary cultivation challenge is poor drainage, which can lead directly to crown or root rot, especially during winter dormancy. To prevent this, provide well-drained soil conditions during planting. Gardeners should also watch for fungal issues like rust, powdery mildew, or leaf spots, which often appear in humid conditions or if air circulation is poor.

Frequently Asked Questions

What hardiness zones is Giant hyssop suitable for?

Agastache rugosa ‘Honey Bee Blue’ is reliably hardy in USDA Zones 5 through 8, though plants in Zone 5 may require extra protection in exposed sites.

How large does Giant hyssop grow?

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

When does Giant hyssop bloom?

This Giant hyssop variety produces blooms from July through September, featuring attractive blue flowers.

What sun exposure does Agastache rugosa ‘Honey Bee Blue’ need?

This plant thrives best in full sun but will tolerate partial shade conditions, provided the location still offers good air movement.

Conclusion

Agastache rugosa ‘Honey Bee Blue’ offers gardeners exceptional value through its intense blue coloration, significant pollinator attraction, and naturally low-maintenance requirements. This reliable Giant hyssop is a fantastic addition to any sunny border or herb collection, provided site preparation prioritizes excellent drainage. Before planting, always check that your soil conditions align with the medium moisture and well-drained needs of this striking perennial.

Wildlife Benefits

The flowers of Agastache rugosa ‘Honey Bee Blue’ are specifically noted for attracting hummingbirds, bees, and butterflies. The whorled, tubular flowers provide an excellent nectar source over a long period spanning July through September. Planting this species directly supports local pollinator populations throughout the warmer months.

Companion Planting

Because Agastache rugosa ‘Honey Bee Blue’ requires excellent drainage and performs best in full sun, match it with other sun-loving perennials that share similar needs. Consider pairing it with drought-tolerant companions like Sedum, ornamental grasses such as Little Bluestem, or other Mediterranean-climate herbs that resent wet feet. Avoid planting near moisture-loving perennials that might keep the soil too damp for the Giant hyssop crown.