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Herbaceous Perennial

Agastache 'Blue Boa'PBR
  • RHS Plants for pollinators

giant hyssop 'Blue Boa'

A herbaceous perennial with bright green, aniseed-scented leaves. Spikes of purple flowers are produced from mid-summer tomid- autumn

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Chalk
Loam
Sand
Moisture
Moist but well–drained, Well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Purple Green
Autumn Purple Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Exposed or Sheltered
Hardiness
H4
Botanical details
Family
Lamiaceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Bushy
Genus

Agastache are herbaceous perennials with simple, aromatic leaves and small 2-lipped tubular flowers in whorls forming dense spikes, in summer and autumn; some are rather tender but can be grown as annual bedding

Name status

Accepted

How to grow

Cultivation

Grow in well-drained, fertile soil in full sun

Propagation

Propagate by division

Suggested planting locations and garden types
  • Cottage and informal garden
  • Gravel garden
  • Mediterranean climate plants
  • Banks and slopes
  • Flower borders and beds
Pruning

Remove spent flowering spikes through the season

Pests

Generally pest-free

Diseases

Generally disease-free

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