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Agastache ‘Blackadder'
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  • Agastache ‘Blackadder'
  • Agastache ‘Blackadder'
Agastache ‘Blackadder'

Agastache ‘Blackadder'

Anise Hyssop
AGASTACHE (Lamiaceae) hyssop

Agastache are upright, aromatic perennials grown for their narrow flower spikes and long summer flowering. Foliage is textured and scented, with notes that vary from mint to anise depending on species. Plants prefer full sun and freely draining soil, where warmth and lean conditions encourage sturdy stems and dense growth. Many forms are drought tolerant once established, though those of cooler origin accept a little more moisture. Flowers are highly attractive to bees, butterflies, and other generalist pollinators.

Clumps can be lifted and divided in spring to maintain vigour. Removing spent spikes can extend the flowering season, though old stems may also be left standing for winter texture. Agastache work well in mixed borders, meadow-style plantings, and gravel gardens where a light vertical structure and reliable mid-season colour are needed.

A tall, steady hyssop known for its dark purple-black calyces, which hold their colour and shape long after the blue flowers are finished. The contrast between the two is clean and understated, giving the plant a longer visual presence than many summer perennials. Spikes remain upright for months, even through our wet winters, and the plant carries a clear vertical line in mixed borders. Nearly sterile, it stays where it is planted and forms a consistent clump over time. Bees work the flowers steadily, and the drying stems add a fine, architectural note as the season shifts.
Pot size
$11.00
Out of stock
Growing Conditions

Light: full sun

Moisture: average to dry

Soil: well drained; lean, sandy, or gravelly soils preferred

Hardiness zone: 5

Maintenance: low; stems can be cut back in spring or left for winter texture; divide as needed to maintain vigour
Size & Habit

Height (cm): 120

Spread (cm): 60

Habit: upright clump
Seasonal Interest

Flowering period: July–Sept

Seasonal interest: summer bloom; lingering purple-black calyces; winter stems

Foliage: green

Flower: blue
Ecology & Notes

Wildlife value: visited by bees and other generalist pollinators

Deer/Rabbit resistance: yes

Habitat: sunny borders; mixed perennial plantings; gravel gardens; wildlife schemes

Features: persistent dark calyces; upright habit; long seasonal presence; nearly sterile

Notes: valued for its structure more than its colour; holds form well into winter

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