About
Eryngium alpinum, the alpine sea holly, is one of the most ornamental of all the sea hollies, producing large, deeply cut, soft-spined, pale-blue or silver bracts surrounding the flowerhead � more feathery and lacier than most species. Upright stems to 70 cm carry the flowerheads in mid to late summer. One of the finest border perennials.
About the genus
Eryngium, the sea hollies, are biennials and perennials with spiny-margined, often architectural leaves and distinctive, dome-shaped flowerheads surrounded by spiny bracts, often in metallic shades of blue, silver or purple. Drought-tolerant and ornamental, they are grown in sunny, well-drained borders.
Growing conditions
SunlightFull sun
Soil typeChalk, Loam, Sand
Soil pHAcid, Alkaline, Neutral
Soil moistureWell-drained
AspectEast-facing, South-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH5
Plant details
Plant typeHerbaceous Perennial
HabitClump forming
FoliageSemi evergreen
Height0.5-1 metres
Spread0.1-0.5 metres
Time to full height2-5 years
Suggested usesCity and courtyard gardens, Coastal, Gravel garden, Patio and container plants, Architectural, Cottage and informal garden, Prairie planting
Native toItaly, Sicilly & Balkans
Care notes
CultivationGrow in dry, well-drained soil that is poor to moderately fertile. Full sun is essential and protect from winter wet
PruningAlthough you can cut back flower stems after flowering the seedheads are a very attractive feature so are usually left over winter
PropagationPropagate by root cuttings in late winter
Pest resistanceMay be susceptible to leaf and bud eelworms, and slugs and snails
Disease resistanceMay be susceptible to root rot and powdery mildews