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Herbaceous Perennial

Eryngium amethystinum

amethyst sea holly

E. amethystinum is a semi-evergreen, clump-forming perennial to around 70cm tall forming a rosette of divided basal leaves. Egg-shaped to rounded, steel blue flowerheads to 2cm long are borne on upright, branching stems often also coloured a deep blue; each flowerhead is surrounded by spreading blue-silver bracts

Other common names
amethyst eryngo
Italian eryngo
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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
Well–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Blue Blue Grey Silver Green
Autumn Green
Winter
Position
  • Full sun
Aspect

East–facing or South–facing or West–facing

Exposure
Exposed or Sheltered
Drought resistance
Yes
Hardiness
H5
Botanical details
Family
Apiaceae
Native to the UK
No
Foliage
Semi evergreen
Habit
Bushy
Genus

Eryngium can be annuals, biennials or perennials with simple or divided leaves, often spiny edged, and cone-like flower-heads often surrounded by an involucre of conspicuous spiny bracts

Name status

Correct

Plant range
Italy, Sicilly & Balkans

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How to grow

Cultivation

Grow in dry, well-drained soil that is poor to moderately fertile. Full sun is essential and protect from winter wet

Propagation

Propagate by root cuttings in late winter

Suggested planting locations and garden types
  • City and courtyard gardens
  • Coastal
  • Gravel garden
  • Patio and container plants
  • Architectural
  • Cottage and informal garden
  • Prairie planting
  • Cut flowers
  • Flower borders and beds
  • Banks and slopes
Pruning

Although you can cut back flower stems after flowering the seedheads are a very attractive feature so are usually left over winter

Pests

Can get leaf and bud eelworms

Diseases

May be affected by powdery mildews and root rot

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