Agastache 'Black Adder'

Agastache 'Black Adder': Bold Spikes and Pollinator Magnetism

Agastache 'Black Adder' is a dramatic and high-performing perennial known for its striking violet-blue flower spikes that rise from near-black buds—creating long-lasting contrast and vivid colour in the summer garden. Beloved by bees, butterflies, and hummingbirds, this cultivar blooms steadily from midsummer into fall, offering both beauty and ecological benefit. Its upright, architectural habit and fragrant licorice-scented foliage make it an ideal choice for sunny borders, prairie-style plantings, and pollinator gardens. With drought tolerance, deer resistance, and an extended bloom period, 'Black Adder' is a garden workhorse with undeniable flair.

Plant Characteristics:

• Height: Reaches 90–120 cm in height, creating strong vertical structure in full-sun borders.
• Spread: Spreads approximately 45–60 cm, forming a tidy, upright clump that remains well-behaved in the garden.
• Flower Colour: Deep violet-blue flowers emerge from dark, nearly black buds for a bold, high-contrast display.
• Flowering Period: Blooms from midsummer into early fall with excellent longevity and rebloom potential.
• Foliage: Aromatic green foliage with a sweet anise scent; adds soft texture and seasonal interest.
• Sunlight Requirements: Thrives in full sun; best flowering and habit occur with at least 6 hours of direct sun daily.
• Soil Requirements: Prefers well-drained soil; tolerates dry, sandy, or gravelly conditions once established.

Uses and Benefits: Agastache 'Black Adder' is perfect for attracting pollinators while anchoring sunny beds with its dark-toned spikes. Its long bloom time and strong upright habit make it a versatile choice for cottage gardens, modern borders, or wildlife-friendly plantings. It performs reliably in hot, dry conditions and is deer resistant, making it well-suited for low-maintenance and drought-tolerant landscapes. Also excellent as a cut flower or dried bloom.

Companion Plants: Pair Agastache 'Black Adder' with Echinacea purpurea 'Magnus'—its bold magenta-pink daisies echo the height and pollinator appeal of the agastache while offering a vibrant colour contrast. Add Achillea 'Sassy Summer Sangria' for its rich red umbels and ferny foliage that bring warmth and texture to the planting. For movement and late-season interest, include Pennisetum alopecuroides 'Hameln'—its fine, arching plumes soften the structure of Black Adder while adding airiness and seasonal elegance. Together, this trio forms a drought-tolerant, pollinator-rich planting that thrives in full sun.

Care Instructions: Water regularly during the first growing season to establish roots. Once established, 'Black Adder' is drought tolerant and thrives with minimal care. Deadhead to encourage continued blooming. Cut back to the base in late fall or early spring. Avoid overly rich soils and overwatering, which can lead to floppy growth.

History: Agastache 'Black Adder' is a hybrid between Agastache rugosa and Agastache foeniculum, developed for its dark, dramatic colouring, dense flower spikes, and strong garden performance. Combining the pollinator appeal and aromatic foliage of both parent species, 'Black Adder' quickly became a favourite for designers and home gardeners alike. Its bold presence, adaptability, and extended bloom period make it one of the most reliable ornamental agastaches available.

Final Thoughts: Agastache 'Black Adder' is a bold, long-blooming perennial that delivers colour, structure, and pollinator appeal to sunny gardens. Whether you’re creating a pollinator haven, spicing up a dry border, or designing a modern prairie, this dramatic cultivar provides lasting impact with very little effort.