Quick Facts

• Mature size: Approx. 700–900mm high x 500–600mm wide

• Position: Full sun

• Foliage: Blue-green, deeply lobed leaves

• Flowering: Summer to early autumn

• Flower colour: Steel-blue, cone-like flower heads with spiky bracts

• Climate tolerance: Heat, frost, and drought tolerant

• Water needs: Low once established

• Maintenance: Low

Why You’ll Love It

Eryngium planum, commonly known as Sea Holly, is a striking architectural perennial prized for its steel-blue flower heads and bold, spiky form. The distinctive flowers are long-lasting and excellent for cutting or drying, while the plant’s tough, drought-tolerant nature makes it ideal for low-maintenance gardens.

Planting & Care Tips

• Plant in full sun for best colour and compact growth

• Prefers well-drained soil; thrives in sandy or gravelly conditions

• Avoid overwatering; drought-tolerant once established

• Minimal disturbance once planted, as it resents transplanting

• Leave flower heads standing for winter interest

• Cut back in late winter or early spring before new growth appears