Giant hyssop (Agastache 'Garden Leader Blue')
Agastache 'Garden Leader Blue' is a low-maintenance Giant hyssop offering showy blue-lavender spikes from July to September, beloved by pollinators.
Complete Plant Information
Overview
The striking Agastache ‘Garden Leader Blue’, commonly known as Giant hyssop, is a superior choice for gardeners seeking long-lasting mid to late-season color. This hardy perennial features dense terminal spikes coated in attractive blue-lavender flowers that maintain their visual appeal for months. Its overall stature, typically reaching two to three feet tall, makes it a perfect vertical accent in sunny perennial beds.
Agastache ‘Garden Leader Blue’ offers significant practical benefits alongside its beauty. The foliage releases a pleasant anise or licorice scent when crushed, and the flowers are magnets for beneficial wildlife, including bees, butterflies, and hummingbirds. Beyond wildlife value, this hybrid is recognized for reliably low maintenance requirements once established in proper conditions.
Gardeners will appreciate the drought tolerance and deer resistance inherent in this variety of Giant hyssop. By ensuring excellent drainage, you provide Agastache ‘Garden Leader Blue’ the perfect environment to thrive, offering consistent performance and vibrant spikes from summer well into autumn.
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-lavender
- Sun Exposure: Full sun
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
The key to successfully establishing Agastache ‘Garden Leader Blue’ is ensuring exceptional soil drainage. Plant this herbaceous perennial in average soil that is medium in moisture, prioritizing locations that receive full sun, although some light afternoon shade is tolerated. Planting in heavy clay soils that retain water is strongly discouraged, as these conditions lead to poor performance and increased risk of winter crown or root rot.
Water requirements are medium during establishment; once mature, this Giant hyssop shows good drought tolerance. Fertilizing is rarely necessary if planted in reasonable soil; these plants generally prefer lean conditions over rich, heavily amended sites. Deadheading spent flower spikes throughout the season is an excellent cultural practice, ensuring a continuous display of blue-lavender blooms extending from July through September.
As the season winds down, be mindful of overwintering requirements, especially in the colder end of its range (Zone 5). While Agastache hybrids exhibit good hardiness, planting in protected spots, like those near a south-facing wall, can aid survival. It is highly recommended to leave the spent flower stems and foliage in place over the winter to provide insulating protection for the crown through the cold months.
Landscape Uses
The structural upright habit and extended bloom period make Agastache ‘Garden Leader Blue’ an ideal choice for mixed sunny borders where continuous texture and color are desired. As bold, aromatic, long-blooming perennials, they function beautifully at the middle or back of a border, providing height without excessive spread. Their vertical lines contrast nicely with mounding or spreading perennials.
Consider planting masses of these Giant hyssops near patios or along walkways where you can easily appreciate the fragrant foliage and the constant buzz of visiting pollinators. They integrate seamlessly into cottage garden designs or more structured contemporary plantings requiring long floral output. Furthermore, cut stems of Agastache ‘Garden Leader Blue’ are excellent for fresh bouquets and dry beautifully for winter arrangements.
Standout Features
Flower Qualities
- Showy
- Good Cut
- Good Dried
Noteworthy Characteristics
Agastache, commonly called giant hyssop, is a genus containing about 30 species of upright herbaceous perennials, most of which are native to North America. Agastache hybrids often have showier flowers and better winter hardiness than species plants. Hybrid flowers come in a variety of different flower colors including shades of red, orange, pink, yellow and white. Hybrids typically feature dense terminal spikes of tiny 2-lipped tubular flowers which bloom mid-summer to fall in many-flowered verticillasters (false whorls) atop 2-4’ tall stiff square stems clad with opposite pairs of serrate, fragrant (anise/licorice scented) gray-green to medium green leaves. Flowers are attractive to bees, hummingbirds and butterflies.Genus name comes from the Greek words agan meaning “very much” and stachys meaning “ear of wheat” in reference to the appearance of the flower spikes.‘Garden Leader Blue’ features lilac blue flowers over a long late June to September (sometimes to frost) bloom period. It typically grows to 2-3’ tall.
Tolerances
- Deer
- Drought
Potential Problems
Crown and root rot is the primary threat to successful cultivation of Agastache ‘Garden Leader Blue’, directly linked to poor soil drainage. The plant cannot tolerate wet feet, especially during winter dormancy. Prevention centers entirely on site selection and soil amendment to ensure rapid water runoff. While generally robust regarding pests, growers should occasionally inspect for rust, powdery mildew, or minor leaf spots, typically signs of poor air circulation or high humidity which can be managed with spacing and pruning. Deer usually find the aromatic foliage unappealing, offering peace of mind in landscapes frequented by browsing animals.
Frequently Asked Questions
What hardiness zones is Giant hyssop suitable for?
Agastache ‘Garden Leader Blue’ is suitable for USDA Hardiness Zones 5 through 8.
How large does Giant hyssop grow?
This variety typically reaches a height of 2 to 3 feet and spreads between 1.5 and 2 feet wide at maturity.
What sun exposure does Agastache ‘Garden Leader Blue’ need?
This plant requires full sun exposure for optimal blooming and performance throughout the summer season.
When does Agastache ‘Garden Leader Blue’ bloom?
The bloom time for this Giant hyssop extends from July to September, featuring attractive blue-lavender flowers.
Conclusion
For reliable, fragrant, and colorful late-season structure, Agastache ‘Garden Leader Blue’ is an indispensable addition to the sunny garden. Its combination of low maintenance, drought tolerance, and proven appeal to pollinators makes this Giant hyssop a modern garden favorite. Before planting, confirm your site offers full sun and excellent drainage to ensure your Agastache ‘Garden Leader Blue’ delivers its signature, long-lasting performance.
Wildlife Benefits
The dense flower spikes are highly efficient at attracting beneficial insects critical to ecosystem health. Hummingbirds are frequently observed feeding from the tubular florets throughout the heat of the summer when other nectar sources may be scarce. Furthermore, the nectar-rich flowers are a favorite landing pad for various species of butterflies and honeybees, making this an excellent plant for dedicated pollinator gardens. Plant five or more together to create a substantial visual and olfactory beacon for wildlife.
Companion Planting
Due to its specific requirement for sharp drainage, Agastache ‘Garden Leader Blue’ pairs well with other Mediterranean or prairie-style perennials that share similar cultural needs. Excellent companions include ornamental grasses like Feather Reed Grass (Calamagrostis) for vertical contrast, or drought-tolerant flowering perennials such as Russian Sage (Perovskia atriplicifolia) and Yarrow (Achillea). Avoid planting near moisture-loving bog plants, as their watering needs conflict directly with the Giant hyssop’s requirement for dry feet.
