Eryngium planum - Sea Holly

Eryngium planum, the sea holly, is a tough, architectural perennial with thistle-like flower cones framed by spiky, metallic bracts in shades of steely blue to silver. It adds striking texture to sunny borders and gravel gardens, and makes an excellent fresh or dried cut flower.

Key features

• Metallic blue to silvery flower cones and bracts, summer
• Long-lasting fresh or dried cut flower
• A magnet for bees and butterflies
• Drought tolerant once established
• Approx. 60–90 cm tall x 45–60 cm wide (varies by variety)

Growing tips

• Full sun (north- or west-facing positions)
• Well-drained, even poor or gravelly soil; avoid winter wet
• Very frost hardy, suited to cold-climate gardens
• Deep taproot, so plant where it can stay; cut back in late winter