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Big Blue Sea Holly

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  • Full Sun (At Least 6 Hours Of Direct Sunlight)
  • Mature Height 24 - 30 Inches
  • Mature Spread 24 - 30 Inches
  • Growing Zones 5 - 8

Big Blue Sea Holly, Star Thistle, Blue Sea Holly, or Eryngium x zabelii ‘Big Blue’, is a stunning, low-maintenance perennial, known for its vivid, color-changing foliage. This remarkable Sea Holly produces spiny, basal clumps of silvery-green foliage that unfurls in late spring with thick thistle-like buds. In late summer to early fall, the buds, spiky foliage, and stiff stems take on a purple to bluish tint that deepens and spreads in color as the season progresses, eventually lending these unique plants their vivid color and brushed metallic sheen. Big Blue Sea Holly ranges in height from 24 to 30 inches with an equal spread. 

Native to southeastern and central Asia, Big Blue Sea Holly has a stiff, upright growing habit and is relatively drought and salt tolerant, especially once the plant is established, and makes a great coastal option. It is a low-maintenance, easy-to-grow option that is deer and rabbit resistant and attracts both butterflies and critical pollinators. It’s used by florists and gardeners alike to provide a unique and colorful flair to arrangements and bouquets, and makes an excellent dried flower option. 

Big Blue Sea Holly Care

Big Blue Sea Holly should be grown in full sun and is very tolerant of hot and dry climates and locations. It can be planted in soil that is dry, sandy and well-drained, slightly acidic to slightly alkaline, and has a pH of 6.0 to 7.8. Sea Holly has deep taproots, which make them difficult to move, so make certain you choose an ideal location before planting. The good news is that this means your Big Blue Sea Holly is drought tolerant. Make certain your Sea Holly has adequate soil drainage. Sea Holly will bloom for a longer period if you deadhead the spent blooms. In late fall or early spring, prune the plants at ground level. 

Big Blue Sea Holly Spacing

Big Blue Sea Holly is an excellent option to bring structure and interest to the back of any garden. It should be spaced 2 to 3 inches apart at planting. They look excellent planted alongside coneflower, which can lend them support when they grow tall.

Big Blue Sea Holly Information

USDA Hardiness Zones: 5 - 8
Plant Type: Perennials
Light Exposure: Full Sun (At Least 6 Hours Of Direct Sunlight)
Mature Height: 24 - 30 Inches
Mature Spread: 24 - 30 Inches
Spacing: 24 - 30 Inches
Habit: Upright
Flower Color(s): Blue
Flower Description:
Bloom Period: July
Foliage Type: Herbaceous
Foliage Color(s): Blue, Green, Silver
Foliage Description: Silvery-Blue. Green
Seasonal Interest: Summer Flowering
Watering: Average
Resists: Deer
Tolerates: Drought
Attracts: Bees, Butterflies
Container Role:
Uses: Containers, Wildlife Gardens
Features: Attracts Pollinators, Cut Flowers, Low Maintenance
Common Name: Big Blue Sea Holly
Other Name(s):
Scientific Name: ERYNGIUM `BIG BLUE`

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Plant Addict Guarantee (Included On All Plant Orders)

Plant Addicts guarantees your plant(s) will arrive happy and healthy, but the plant(s) are being shipped through the mail and accidents happen. If the plant is dead, has dried out roots or the incorrect item was shipped just notify Plant Addicts within 3 days upon delivery. We may ask for pictures but will try to make it as easy as possible for you. Please note plant(s) with damaged branches or wilted leaves will not qualify for this guarantee. Plants are very resilient and will rebound quickly when cared for correctly.

For information on how to care for you new plant please check out our guide. Guide: How to Care for Your New Plant(s)

Plant Addicts Warranty - 1 Year (Extra Purchase Required)

We encourage all plant lovers to purchase the Plant Addicts Warranty whether you’re new or an expert. There are many variables outside our control and yours that can cause the demise of your plant(s). Examples would be hungry animals, drought, poor soil conditions, over watering, disease, insects & many other factors. The Plant Addicts Warranty is a 1 year warranty protecting you from all the unknowns and will replace your plant if it moves on to the plant afterlife.

The warranty is purchased on a per plant basis and must be purchased at the same time as the plant purchase. We will cover 100% of the price of the plant but the warranty does not cover shipping cost. Simply let us know if your plant has died within one year of receiving it and we’ll get you a new one shipped out. We may ask for photos for documentation purposes but again we’ll try to make it as easy as possible.

For more information, please go to our Shipping & Returns page at the bottom of the website.

Guide: How to Care for Your New Plant(s)

Planter Shipping

Standard Colors: 2-3 business days

Special Order Colors: 8 weeks - this is due to the planter being custom made with the color(s) of your choice

Please Note: On special orders there can not be any cancellations

Plant Shipping

Time of Order:

Summer Shipping

  • If there is extreme heat we’ll delay shipping.  
    • We’ll have to review what areas the plants are traveling through along with your location

Once your plant is shipped you’ll receive an email with tracking information. Depending on the above criteria we’ll ship your plant(s) towards beginning of the following week from your order. We put together this helpful guide of what to do when you receive your plants in the mail.

It is important to know that all of our plants are clearly labeled for which growing zones the plant can survive in. The plants are thoroughly trialed and tested in every growing zone before we state the plant can grow in a zone. Again, our #1 priority is to ship the plants to you healthy and ready to thrive in your location. So we will do everything in our power to do so.