Agastache Blue Boa (Giant Hyssop)

Adding lovely vertical lines to the landscape, Agastache ‘Blue Boa’ (Giant Hyssop) is a striking, upright herbaceous perennial forming a low tight mound of aromatic, ultra-green leaves. From early summer to fall, it boasts long and dense spikes of deep violet-blue flowers.

Adding lovely vertical lines to the landscape, Agastache 'Blue Boa' (Giant Hyssop) is a striking, upright herbaceous perennial forming a low tight mound of aromatic, ultra-green leaves. From early summer to fall, it boasts long and dense spikes of deep violet-blue flowers. They stand out in the garden and provide a bold visual appeal. Loved by bees and hummingbirds, it is perfect for use in sunny borders.

  • Grows up to 30-36 in. tall (75-90 cm) and 24 in. wide (60 cm). The aromatic leaves exude a licorice scent when crushed.
  • Easily grown in full sun, in average, dry to medium moisture, well-drained soils. Good drainage is particularly important. Although a drought-tolerant plant, it might need watering in extreme dry weather spells.
  • Provides a bold visual impact in beds and borders, cottage gardens, gravel gardens, butterfly gardens, or banks and slopes over a very long season.
  • Ideal to add color to the late-season garden when many other plants are fading.
  • Creates a stunning effect when mixed with other perennials or planted en masse.
  • Attracts streams of hummingbirds, butterflies, and other beneficial pollinators.
  • Generally disease and pest-free (might occasionally be subject to powdery mildew) and resistant to deer and rabbits.
  • Deadhead spent flowers to promote additional bloom.
  • Propagate by division in spring.

Requirements

Hardiness 5
– 9

Heat Zones 5
– 12

Climate Zones 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Perennials
Plant Family Agastache – Hyssops
Exposure Full Sun
Season of Interest Summer (Early,Mid,Late)Fall
Height 2'
– 3'
(60cm
– 90cm)
Spread 1'
– 2'
(30cm
– 60cm)
Spacing 24″ (60cm)
Water Needs Low
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Cut Flowers, Fragrant, Showy
Tolerance Deer, Drought, Rabbit
Attracts Bees, Butterflies, Hummingbirds
Garden Uses Banks and Slopes, Beds and Borders
Garden Styles Gravel and Rock Garden, Informal and Cottage