Agastache flowers

A group of sun-loving, semi-hardy, herbaceous perennials with attractive summer flowers. As members of the mint family they usually have aromatic foliage. The abundant upright flower spikes are loved by pollinators.

Family: Lamiaceae
Botanical Name: Agastache
Common Names: Korean mint, summer hyssop, anise hyssop, giant hyssop.

Foliage: Deciduous, simple, aromatic leaves.

Flowers: Upright or tufted spires of small tubular flowers. Predominantly blue and lilac, but also available in pastel shades of apricot, red, pink and yellow.

Flowering Period: Mid-summer to early autumn.

Soil: Moist but well-drained soil (Clay, sand or loam). Acid, alkaline or neutral pH.

Conditions: Full sun. Plant in a west or south facing aspect, in a sheltered position.

Habit: Bushy.

Type: Herbaceous perennial.

Origin: USA and Asia.

Hardiness: Hardy to semi-hardy.

Planting and Growing Agastache

Easy to grow. Thrives in any good, moist but well-drained soil, in a sunny position. Ensure the soil is very free draining as the plants can easily rot in wet soil, especially during winter.

Ideal for choice flower beds or front/middle of the border.

Taking Care of Agastache

Tender species can be overwintered as rooted cuttings in the greenhouse. Alternatively, treat as an annual and raise from seed each year.

Pruning Agastache

Trim back old flower stems in late autumn.

Pests and Diseases

Can be affected by powdery mildews.

Propagating Agastache

Increase from seed or by division in spring. 

Semi-ripe cuttings of tender species can be rooted in late summer and overwintered in a frost free area.

Varieties of Agastache

The two main groups (rugosa and aurantiaca) differ slightly in habit and flower colour.

Agastache rugosa is an upright robust form with spires of flowers in shades of blue and white. One of the hardiest species which usually survive mild winters in the UK.

  • 'Blue Boa' bears fat blue flower spikes from June to October. Half-hardy. Foliage has a liquorice aroma. Height 24in (60cm), spread 18in (45cm).
  • 'Blue Fortune' is a bold, tall leafy perennial. Blue flowers in summer. Reasonably hardy. Height 36in (90cm), spread 18in (45cm).
  • 'Golden Jubilee' has lemon foliage and lavender-blue flower spikes. Foliage has an aniseed aroma.
  • 'Kudos Gold' forms a neat compact mound of spear-shaped, grey-green leaves. Golden-orange flowers. Height and spread 20in (50cm).
  • 'Raspberry Summer' forms a clump of aromatic, bright green leaves. Spikes of pink flowers in summer. Height 36in (90cm), spread 24in (60cm).
Agastache aurantiaca is a smaller, shrubbier more colourful species. Originating from Mexico, it is semi-hardy and usually grown as an annual in the UK.
  • 'Apricot Sprite' is a compact form with apricot-orange flowers and silvery-green foliage. Half-hardy. Height 18in (45cm), spread 12in (30cm).