Sea holly

RHS Genus Guide

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.

Botanical name: Eryngium

RHS / Sarah Cuttle

Appearance

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.

Preferences

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.

RHS Recommended

Sea holly

tall eryngo 'Silver Ghost'

Eryngium giganteum 'Silver Ghost'

tall eryngo 'Silver Ghost'

Height: 0.5–1 metres
Width: 0.1–0.5 metres

eryngo [Picos Amethyst]

Eryngium bourgatii Picos Amethyst ('Mackpam'^PBR)

eryngo [Picos Amethyst]

Height: 0.1–0.5 metres
Width: 0.1–0.5 metres

pandan-like-leaved eryngo

Eryngium pandanifolium

pandan-like-leaved eryngo

Height: 1.5–2.5 metres
Width: 1–1.5 metres

eryngo 'Picos Blue'

Eryngium bourgatii 'Picos Blue'

eryngo 'Picos Blue'

Height: 0.5–1 metres
Width: 0.1–0.5 metres

tripartite eryngo

Eryngium × tripartitum

tripartite eryngo

Height: 0.5–1 metres
Width: 0.1–0.5 metres

Award of Garden Merit

Plants for pollinators

See all Sea holly