Introducing...
Sea holly
Botanical name: Eryngium
These architectural, spiny, almost sculptural perennials, some looking superficially like thistles, can make a dramatic statement in a summer border. Let them rise above low-growing plants, or mingle them among roses and taller perennials to provide a contrast in form and texture.
Looks
Upright, branching stems bear greenish-white or blue flowers gathered into a cone surrounded by a ruff of spiny bracts. In some, the upper part of the plant is suffused with metallic blue.
Likes
Most like very free-draining soil, some even thriving in poor, dry soil, in sun.
Dislikes
Very fertile, overly rich soils are unsuitable, as is a position in shade.
Did you know?
The flowers are long-lasting and can be cut and dried for use in winter arrangements.
Sea hollies we recommend
Eryngium bourgatii 'Picos Blue'PBR
sea holly 'Picos Blue'
- 0.5–1 metres
- 0.1–0.5 metres
Eryngium giganteum 'Silver Ghost'
tall eryngo 'Silver Ghost'
- 0.5–1 metres
- 0.1–0.5 metres
Eryngium bourgatii Picos Amethyst ('Mackpam'PBR)
sea holly 'Picos Amethyst'
- 0.1–0.5 metres
- 0.1–0.5 metres
Eryngium bourgatii 'Picos Blue'PBR
sea holly 'Picos Blue'
- 0.5–1 metres
- 0.1–0.5 metres
Eryngium giganteum 'Silver Ghost'
tall eryngo 'Silver Ghost'
- 0.5–1 metres
- 0.1–0.5 metres
Eryngium bourgatii Picos Amethyst ('Mackpam'PBR)
sea holly 'Picos Amethyst'
- 0.1–0.5 metres
- 0.1–0.5 metres
Useful advice
Cut flowers: growing and selection
Perennial borders: choosing plants
Perennials: cutting back
Perennials: dividing
Seed: collecting and storing
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.