Blue Sea Holly – How to Sow, Grow and Enjoy 5 of the Best Eryngium for Full-Sun Gardens.

Blue Sea Holly – How to Sow, Grow and Enjoy 5 of the Best Eryngium for Full-Sun Gardens.

Blue Sea Holly is a striking, architectural, often silverized annual or short-lived perennial thistle you will want to grow from seed. Often seed in designer gardens, blue sea holly brings a bold dramatic effect to any garden.

Best started from seed sown in Fall, Eryngium, often referred to as blue sea holly is a genus with over 200 hundred species with wide distribution globally, a large number of which are found native in Central America.

5 of the best Eryngium to grow from seed favor dry, free-draining, full-sun locations. Once germinated the plant prefers to grow undisturbed and is best sown from seed sown directly where they are to flower.


Bees are attracted to the nectar of sea holly and despite the thistle appearance, butterflies and pollinators are regular visitors to this rosette-forming, spiny perennial umbel. Be warned the pollinators can navigate the spines, pets should avoid touching the spines and gardeners should wear thick gloves when clean-up in the spring necessary.

How to Sow:

I have had the best results when sowing Eryngium direct in Fall or simply allowing the parent plant to set seed and leaving the seeds to naturally scarify and subsequently germinate.

Re-locating self-sown seeds of blue sea holly should be attempted as the seedling produces its true leaves a few weeks after germinating, this way you are unlikely to damage the delicate taproot.

Grow with:

Native Echinacea, Geum, Achillea, Rudbeckia, Oenothera, and Monarda these 6 perennials provide additional seasonal interest, and as the sea holly is long flowering, dry well and can be left standing through winter allowing a fifth season to be enjoyed by wildlife and winters brave garden visitors.

If purchasing seeds in Spring then chill for a few weeks in the vegetable draw of the refrigerator prior to sowing where they are to flower.

5 Best Eryngium:

There are several notable species and cultivars of sea holly that are worthy of a place in your pollinator garden.

E. alpinum – heart shaped leaves and the bluest of flower bracts.

E. bourgatti – metallic blue bracts and flower stems.

Eryngium zabelli “Big Blue” – a cultivar resulting from a cross between species E. alpinum and E. bourgatti.

E. planum – silver blue flower stems often used as a cut flower.

E. yuccifolium – great for naturilizing may need to be kept in check and some seedlings removed as ongoing maintenance.

Plant Magick:

If Love, harmony, and marital bliss are in order then Eryngium is the plant for you, growing sea holly around the garden will help bring peace. Try burning the dried flower stems as incense or use in a love spell to help to re-ignite passion.

I find growing plants from seed incredibly rewarding, even the smallest of outdoor garden areas can be a productive workout for all the family. Try thinking of your garden as a living kitchen and grow to love fresh flowers, organic fruit, and vegetables straight from your own backyard oasis.

Stephen Pryce-Lea

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