Eryngium amethystinum
amethyst sea holly
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
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Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| 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 ShelteredDrought resistance
Yes Hardiness
H5Botanical details
- Family
- Apiaceae
- Native to the UK
- No
- Foliage
- Semi evergreen
- Habit
- Clump forming
- 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
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
May be susceptible to leaf and bud eelworms, and slugs and snails
Diseases
May be susceptible to root rot and powdery mildews
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