Create Your Garden

Eryngium x oliverianum (Oliver Sea Holly)

Oliver Sea Holly, Oliver Eryngo

AGM Award
Eryngium x oliverianum, Oliver Sea Holly, Oliver Eryngo, Blue flowers, Blue perennials
Eryngium x oliverianum, Oliver Sea Holly, Oliver Eryngo, Blue flowers, Blue perennials

Eryngium x oliverianum (Oliver Sea Holly) is an upright perennial with basal rosettes of heart-shaped, strongly toothed, dark green leaves. From mid-summer to early fall, sturdy leafy violet-blue stems bear large, cone-shaped, thistle-like, blue to lavender-blue flower heads. Each flower head is surrounded by narrow, spiny, metallic-blue bracts. Attractive to bees and butterflies but deer resistant, this striking Sea Holly survives in a wider range of soil types than many more difficult eryngiums. Eryngium x oliverianum is a cross between E. planum and E. giganteum. According to many, it has the strongest blue stems and flowers of any eryngiums.

  • Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society.
  • Grows in clumps of stiffly erect, branched stems up to 24-36 in. tall (60-90 cm) and 18-24 in. wide (45-60 cm)
  • Performs best in full sun in fairly dry, poor to moderately fertile well-drained soils. Tolerates light shade, poor soils, drought, and salt.
  • Excellent choice for gravel gardens, cottage gardens, and coastal gardens. May be planted as a single specimen or in groupings. Perfect for cut or dried flower arrangements too!
  • Although you can cut back flower stems after flowering the seedheads are a very attractive feature so are usually left over in winter
  • Watch for leaf and bud eelworms, powdery mildew, and root rot.
  • Propagate by root cuttings in late winter

Learn How To Plant, Care, and Grow Spectacular Sea Holly (Eryngium)


Attractive, Sea Holly plants (Eryngium) are striking ornamental perennials grown for their arresting, thistle-like, silvery or blue tinted flower heads adorned with a ruff of showy bracts. Blooming in summer and sometimes into fall, they are exceptionally care-free plants if they are given a well-chosen site. Here are some basic rules that need to be followed to enjoy their splendid flowers.

Requirements

Hardiness 5 - 8
Heat Zones 5 - 8
Plant Type Perennials
Plant Family Apiaceae
Genus Eryngium
Common names Sea Holly
Exposure Full Sun
Season of Interest Summer (Mid, Late)
Fall
Height 2' - 3'
(60cm - 90cm)
Spread 1' - 2'
(30cm - 60cm)
Spacing 24" (60cm)
Maintenance Low
Water Needs Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Well-Drained
Characteristics Dried Arrangements, Cut Flowers, Plant of Merit, Showy
Tolerance Drought, Deer, Salt, Dry Soil
Attracts Bees, Birds, Butterflies
Garden Uses Beds And Borders
Garden Styles Coastal Garden, Gravel and Rock Garden, Informal and Cottage, Prairie and Meadow
How Many Plants
Do I Need?
Explore Great Plant Combination Ideas
Eryngium (Sea Holly)
Not sure which Eryngium (Sea Holly) to pick?
Compare Now

Alternative Plants to Consider

Eryngium leavenworthii (False Purple Thistle)
Eryngium alpinum ‘Blue Star’ (Alpine Sea Holly)
Eryngium planum ‘Blue Cap’ (Flat Sea Holly)
Eryngium alpinum (Alpine Sea Holly)
Eryngium x tripartitum (Tripartite Sea Holly)
Eryngium amethystinum (Amethyst Sea Holly)

Recommended Companion Plants

Achillea millefolium ‘Red Velvet’ (Yarrow)
Stachys byzantina (Lamb’s Ears)
Stipa tenuissima (Mexican Feather Grass)
Perovskia ‘Blue Spire’ (Russian Sage)

Find In One of Our Guides or Gardens

How to Create an Enchanting Butterfly Garden
For the Love of Butterflies: Best Flowers to Attract them to Your Garden
6 Reasons You Should Create a Butterfly Garden
For the Love of Bees: Best Flowers to Attract them to Your Garden
How to Cultivate a Thriving Bee-Friendly Garden
Eryngium (Sea Holly)
Eryngium bourgatii (Mediterranean Sea Holly)
Eryngium planum (Flat Sea Holly)
Learn How To Plant, Care, and Grow Spectacular Sea Holly (Eryngium)
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.
Buy Plants

Requirements

Hardiness 5 - 8
Heat Zones 5 - 8
Plant Type Perennials
Plant Family Apiaceae
Genus Eryngium
Common names Sea Holly
Exposure Full Sun
Season of Interest Summer (Mid, Late)
Fall
Height 2' - 3'
(60cm - 90cm)
Spread 1' - 2'
(30cm - 60cm)
Spacing 24" (60cm)
Maintenance Low
Water Needs Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Well-Drained
Characteristics Dried Arrangements, Cut Flowers, Plant of Merit, Showy
Tolerance Drought, Deer, Salt, Dry Soil
Attracts Bees, Birds, Butterflies
Garden Uses Beds And Borders
Garden Styles Coastal Garden, Gravel and Rock Garden, Informal and Cottage, Prairie and Meadow
How Many Plants
Do I Need?
Explore Great Plant Combination Ideas
Eryngium (Sea Holly)
Not sure which Eryngium (Sea Holly) to pick?
Compare Now

Gardening Ideas

Plant Calculator

How many Eryngium x oliverianum (Oliver Sea Holly) do I need for my garden?

Input your garden space dimensions

Your Shopping List

Plant Quantity
Eryngium x oliverianum (Oliver Sea Holly) N/A Buy Plants

Please Login to Proceed

You Have Reached The Free Limit, Please Subscribe to Proceed

Subscribe to Gardenia

To create additional collections, you must be a paid member of Gardenia
  • Add as many plants as you wish
  • Create and save up to 25 garden collections
Become a Member

Plant Added Successfully

You have Reached Your Limit

To add more plants, you must be a paid member of our site Become a Member

Update Your Credit
Card Information

Cancel

Create a New Collection

Sign Up to Our Newsletter

    You have been subscribed successfully

    Join Gardenia.net

    Create a membership account to save your garden designs and to view them on any device.

    Becoming a contributing member of Gardenia is easy and can be done in just a few minutes. If you provide us with your name, email address and the payment of a modest $25 annual membership fee, you will become a full member, enabling you to design and save up to 25 of your garden design ideas.

    Join now and start creating your dream garden!

    Join Gardenia.net

    Create a membership account to save your garden designs and to view them on any device.

    Becoming a contributing member of Gardenia is easy and can be done in just a few minutes. If you provide us with your name, email address and the payment of a modest $25 annual membership fee, you will become a full member, enabling you to design and save up to 25 of your garden design ideas.

    Join now and start creating your dream garden!

    Find your Hardiness Zone

    Find your Heat Zone

    Find your Climate Zone