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Eryngium plants, often referred to as “sea hollies,” are a delightful addition to any garden. With their striking blue or silver thistle-like blooms and unique foliage, Eryngiums can add a touch of elegance to your outdoor space. In this article, we’ll explore the fascinating world of Eryngium plants, from understanding their characteristics to mastering the art of cultivation.

How to grow Eryngium

To grow Eryngium, plant in well-drained soil with full sunlight. Water sparingly, allowing the soil to partially dry. These hardy perennials thrive in the UK climate, offering spiky, metallic-blue blooms that add unique texture and visual interest to your garden with minimal care.

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Understanding Eryngium

Eryngium plants, often known as “sea hollies,” are a group of perennials renowned for their striking appearance and unique features. These plants are characterized by their:

Botanical Features

  • Elegant Appearance: Eryngiums boast stunning blue or silver thistle-like flowers that make them stand out in any garden.
  • Attractive Foliage: The spiky leaves of Eryngium plants add texture and visual interest to your garden.
  • Longevity: Eryngiums are perennials, which means they can grace your garden year after year with proper care.

Origins and Habitat

Eryngiums are native to various regions, including Europe, North and South America, and the Mediterranean. They thrive in coastal areas and are often found near the sea, hence their common name, “sea hollies.” Understanding their natural habitat can help you recreate ideal growing conditions.

Getting Started with Eryngium

Now that you’re acquainted with the charm of Eryngium, let’s dive into the practical aspects of growing these lovely plants.

Ideal Climate and Soil Conditions

Eryngiums flourish in regions with:

  • Full Sun: These sun-loving plants thrive when exposed to full sunlight for most of the day.
  • Well-Drained Soil: Good drainage is crucial to prevent root rot. Sandy or loamy soil works well for Eryngium.
  • Moderate Temperatures: While Eryngiums can tolerate a range of temperatures, they prefer mild climates.

Selecting the Right Location

Before you start planting Eryngium, choose a suitable spot in your garden. Consider the following factors:

  • Sun Exposure: Ensure the chosen location receives ample sunlight.
  • Space: Eryngium plants can spread, so provide enough space for them to grow freely.
  • Companion Plants: Plan companions that complement Eryngium’s colors and size.

Soil Preparation and Drainage

Proper soil preparation is essential for Eryngium’s success:

  • Soil Testing: Conduct a soil test to assess its pH and nutrient levels.
  • Amendments: Add organic matter like compost to improve soil fertility.
  • Drainage: Ensure good drainage to prevent waterlogged roots.

Planting Eryngium

Now that you’ve prepared the soil and selected the perfect spot, it’s time to plant your Eryngium seeds or seedlings.

Planting Depth and Spacing

  • Seeds: If planting from seeds, sow them at a depth of approximately ¼ inch.
  • Seedlings: If using seedlings, space them about 12 to 18 inches apart to allow for their mature size.


  • Initial Watering: After planting, give your Eryngium a thorough watering.
  • Established Plants: Once established, water moderately, allowing the soil to dry slightly between waterings.

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Transplanting Eryngium

If you’re starting with established seedlings, follow these steps for successful transplanting:

  • Carefully dig up the seedlings, taking care not to damage the roots.
  • Dig a hole in the new planting location and place the seedling in it at the same depth as it was previously.
  • Water the transplanted seedling thoroughly to help it settle into its new home.

Eryngium Care and Maintenance

Eryngiums are relatively low-maintenance plants, but they do require some care to thrive.

Watering Requirements

  • Consistent Moisture: Keep the soil consistently moist but not waterlogged.
  • Drought Tolerance: Eryngiums are drought-tolerant once established, making them a resilient choice for your garden.

Mulching and Weed Control

Fertilizing Eryngium

  • Minimal Fertilization: Eryngiums don’t require heavy fertilization. A balanced, slow-release fertilizer applied in spring is usually sufficient.

Dealing with Common Eryngium Plant Issues

Despite their resilience, Eryngium plants can face a few common issues.


  • Aphids: Aphids may occasionally infest Eryngiums. Use insecticidal soap or neem oil to control them.
  • Snails and Slugs: These pests can damage Eryngium leaves. Set up traps or use organic slug and snail bait.


  • Powdery Mildew: Eryngiums are susceptible to powdery mildew. Ensure good air circulation and use fungicides if needed.
  • Crown Rot: Prevent crown rot by ensuring proper drainage and avoiding overwatering.

Eryngium Propagation

Eryngiums can be propagated through various methods, including division and cuttings.


  • Spring Division: Divide mature Eryngium plants in spring before new growth begins.
  • Steps: Dig up the plant, separate the root clumps, and replant them in new locations.


  • Softwood Cuttings: Take softwood cuttings in early summer for successful propagation.
  • Rooting Hormone: Dip cuttings in rooting hormone before planting them in pots with well-draining soil.

Pruning and Deadheading Eryngium

Pruning and deadheading can help maintain the appearance and health of your Eryngium plants.

Pruning Benefits

  • Improved Appearance: Pruning can encourage bushier growth and more flowers.
  • Removal of Dead Growth: Trim dead or damaged stems to keep your Eryngium looking its best.

When to Prune

  • Late Spring: Prune in late spring when new growth begins to emerge.

Eryngium in Garden Design

Eryngiums are not only beautiful but also versatile in garden design.

Companion Planting

  • Lavender: Pair Eryngiums with lavender for a stunning blue-purple color combination.
  • Grasses: Ornamental grasses provide a contrasting texture alongside Eryngium’s spiky leaves.
  • Perennials: Combine Eryngium with other perennials for year-round interest.

Color Schemes

  • Blue and Silver: Emphasize Eryngium’s natural colors by incorporating blue and silver elements in your garden design.
  • Monochromatic: Create a monochromatic scheme with various shades of blue and silver for a cohesive look.

Frequently Asked Questions (FAQs)

Propagating Eryngium

Division Method

One effective way to propagate Eryngium is through division. This method is best done in the spring before new growth begins. Here’s how to do it:

Step Instructions
1. Choose a Mature Plant Select a mature Eryngium plant for division.
2. Dig Up the Plant Gently dig up the entire plant, taking care not to damage the roots.
3. Divide the Root Clumps Divide the root clumps into smaller sections.
4. Replant the Sections Replant the divided sections in new locations, ensuring they have well-draining soil.
5. Water Thoroughly After replanting, water the newly divided Eryngium sections thoroughly to help them establish.

Cuttings Method

Softwood cuttings can also be used for propagating Eryngium. Here’s a brief guide:

Step Instructions
1. Take Softwood Cuttings In early summer, select soft, non-woody stems from the Eryngium plant.
2. Use Rooting Hormone Dip the cut end of each stem in the rooting hormone to encourage root development.
3. Plant in Pots Plant the cuttings in pots with well-draining soil.
4. Provide Adequate Care Keep the cuttings in a sheltered spot and maintain moisture until they root.

Creative Garden Design with Eryngium

Eryngiums are not just garden beauties; they can be versatile assets in your garden design. Here are some creative ideas:

Companion Planting

Eryngiums pair beautifully with various other plants. Consider these companion planting options:

Companion Plant Reasons to Pair
Lavender The purple-blue hues of Eryngium complement lavender’s color, creating a harmonious combination.
Grasses Ornamental grasses provide contrasting texture alongside Eryngium’s spiky leaves.
Perennials Combine Eryngium with other perennials for a diverse and dynamic garden.

Color Schemes

Eryngiums come in stunning shades of blue and silver. Here are some color scheme ideas:

Color Scheme Description
Blue and Silver Emphasize Eryngium’s natural colors with a monochromatic palette of blue and silver elements.
Monochromatic Create a unified look by using various shades of blue and silver throughout your garden.

Frequently Asked Questions (FAQs)

Now, let’s address some common questions about Eryngium:

The best time to divide Eryngium plants is in the spring, before new growth begins. This allows the divided sections to establish themselves during the growing season.

Yes, Eryngiums are known for their drought tolerance once they are established. However, it’s essential to provide adequate moisture during the initial establishment phase.

To prevent powdery mildew, ensure good air circulation around your Eryngium plants. Additionally, you can use fungicides if the mildew becomes a problem.

Yes, Eryngium plants can be susceptible to crown rot if they are planted in soil with poor drainage. It’s crucial to ensure proper drainage to avoid this issue.

Yes, Eryngiums can be grown in containers. Choose a large enough pot with well-draining soil, and provide regular water and sunlight.