Eryngium ‘Big Blue’ Sea Holly Makes a Garden Statement


Eryngium ‘Big blue’ Sea Holly, at home in the sun in containers and gardens

Eryngium 'Big Blue'
Eryngium ‘Big Blue’

Add a statement to your garden! Eryngium x zabelii ‘Big Blue’ (USPP#20636, PBR 28175) comes to Rozanne and Friends® from Myerscough College of Preston, in Lancashire, UK.

The electric-blue flower heads have 4-inch (10 cm) wide bracts and the striking color extends down onto spiky foliage and along flower stems. Makes larger, taller plants than Eryngium ‘Blue Sapphire’.

Commonly known as “Sea Holly”, this variety originates from its native costal home. The spiny leaves, flowers and bracts refer to similar spiny leaf features of the evergreen shrub, Holly. Plants within this genus thrive in dry, sunny locations. ‘Big Blue’ Sea Holly loves the sun, so much that when in shade its color dilutes.

In the garden, often the highlight of one’s home exterior, the ‘Big Blue’ Sea Holly is a great accent plant for middle border gardens. But, you don’t have to limit this variety to only the garden’s border, as is also an impressive display en masse. Beyond the garden, mixing ‘Big Blue’ Sea Holly with other perennials creates beautiful and novel containers. Plants are also useful for cut and dried flowers, are attractive to butterflies and have a long bloom period in summer.

For Growers

  • Typically plant 1 liner per 4.5-inch (11 cm), 6-inch (15 cm) or 1-gallon (4 litre) pots.
  • Vernalization is required and plants need extra time to size up before overwintering. Plant in late summer to early fall and allow plants to bulk before vernalization. Overwinter outdoors or inside cold greenhouses. Allow plants to emerge and flower with naturally occurring spring temperatures. This method provides larger plants, more uniformity and more flowers.
  • Alternatively, plant vernalized liners in March and April. However, plants will not be as uniform, full or floriferous as in bulked, overwintered crops.
  • Standard media pH: 5.5 to 6.5; standard media EC 1.5 to 3 mmhos/cm.
  • Water thoroughly but allow to dry slightly between irrigations.
  • Primary problem can be root rot.
  • See our Technical Guide for more information.

 In the garden

  • For middle garden borders accent plants or as massed plantings. Also, nice novelty plant for containers.
  • Plants are useful for cut and dried flowers, are attractive to bees and butterflies and have a long bloom period in summer.
  • USDA Hardiness Zone: 5 to 9.
  • Grow in full sun.
  • Spread 26 inches (66 cm).
  • Height 33 inches (84 cm).
  • Prefers well-drained garden soils.


Getting to know the Must Have Perennials™ – The plants your garden would choose