Blue Sea Holly - Expert growing tips

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.

Pollinators:

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 I Grow Eryngium:

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.

ERYNGIUM SOWING TIPS:

Note: Two months of cold stratification or direct sowing or winter dormancy is required!

SOWING DIRECT TIPS:

Direct sow seeds in fall and allow seeds to naturally cold stratify, this way they will germinate in Spring as temperatures improve. Leave undisturbed where they are to flower.

COMMERCIAL SECRETS TO STRATIFICATION:

Place Eryngium SEEDS in a zipper bag or cover pots/trays with black plastic after watering and seal with a rubber band then cold stratify in the fridge for 60 days.

Keep soil moist, not wet. At the end of the cold stratification, remove black plastic from pots and place trays in a warm, sunny location.

SOWING SEEDS INDOORS:

When starting seeds indoors, sow finely and gently press seeds to make contact with soil as light is required for germination.

Start in trays or small pots on a window sill or glasshouse several weeks before the last frost in your area.

HARDENING OFF:

Seeds started indoors will need acclimatizing to outdoor tempertures, this should be done gradulay by placing young plants in a shady location outdoors during the warmer part of the day, slowly increase the time to harden plants to spring tempertures.

Planting out:

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.

Planting out seedlings that have been grown indoors, should be carried out with care, watering the pots or trays well prior to transferring from pots will minimize root disturbance.

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.

Eryngium Sea Holly Blue Thistle Seed Flower Garden Pollinator

Eryngium Sea Holly Blue Thistle Seed

Eryngium planum or sea holly blue thistle flower is an architectural garden perennial that shimmers steely blue

Sea Holly is incredibly popular with butterflies and late-season pollinators, a must for every garden in fall.

Easily germinated from seed this plant prefers to be sown direct and self-seeds freely without being a nuisance.

Eryngium is a fast-growing, long season flowering, short-lived perennial best grown as an annual that self-seeds freely.

Eryngium or Sea Holly flowers freely in full sun, and can maintain during drought conditions, stands up well to foraging wildlife, Tiny steel blue flowers appear in abundance, and create flower clusters on long wiry stems that appear largely resilient to rabbits and deer.

A spectacular display in gardens and borders, blue sea holly can be dried and holds the blue color well in arrangements.

Sow direct in late Fall or Spring.

Eryngium planum seeds can be started outdoors in the fall, or spring, or start indoors a few weeks ahead of the last frost date.

Flowering late Summer thru Fall, and loved by an array of pollinators, particularly swallowtail butterflies and bees, and plentiful seed for fall birds.

Harvested from my own pollinator-friendly plants these blue sea holly make a cheerful addition to any butterfly or wildflower garden.

Thriving on poor soils in full sun, on the prairie, or at home in the cottage garden, plant with rudbeckia, goldenrod, and fall asters.

We hand collect and clean our seeds freshly collected in 2021 seeds, sow seeds that have been kept refrigerated for 4 or more weeks to help break seed dormancy.

Easy to grow sow seeds direct where you would like them to flower, in Fall or Early Spring, approx pack quantity minimum of 10 – 100 seeds

How to grow from seed a growers guide to germination will help you get the best start for your seeds see menu for link.

SOWING TIPS:

Direct sow seeds in fall and allow seeds to naturally cold stratify. When starting seeds indoors, sow finely and barely cover seeds with soil. I recommend sowing these seeds, direct in Fall on a prepared seedbed or garden container, water well, and protect from winter weather with a fabric fleece if some seeds germinate early.

1) Sow direct in a prepared seedbed
2) Cold frame sheltered location outdoors
3) Under lights
4) Bright windowsill

I like to grow in pots this way you can break dormancy, simply by moving the pots around and most seeds germinate in batches, care must be taken when picking out to avoid disturbing emerging seedlings.

Pot young plants on until large enough to plant out, this native plant mix prefers poor soil in full sun.

Alternatively use the following techniques to improve germination

SEED COUNT:

Average of 25+ seeds per pack. Cold Stratification or Direct Sowing: Recommended. (See Winter Jug Method)

Direct sow seeds in fall and allow seeds to naturally cold stratify. When starting seeds indoors, sow finely and barely cover seeds with soil.

I recommend sowing these seeds, direct in Fall on a prepared seedbed or garden container, water well, and protect from winter weather with a fabric fleece if some seeds germinate early. Also known as cold stratification and can be completed anytime of the year by placing seed packs in a cool drawer of a refrigerator for 4-12 weeks to break seed dormancy.

1) Sow direct in a prepared weed-free seedbed
2) Cold frame sheltered location in small pots outdoors
3) Under lights indoor grow room
4) Bright windowsill with drip tray and propagator cover

Pot young plants on until large enough to plant out, this native plant mix prefers poor soil in full sun.
Full instructions, border design and planting ideas available online by searching igrowhort native-seed-collections.

Native plants maintain balance and provide habitat and eco-systems for resident and migratory wildlife. Due to many years of ecological destruction, development and toxic pollution many native wild flowers, and wildlife are under-threat of extinction.

We all have an important role to play, no matter how small your garden or balcony a few plant pots filled with natives instead of alien ornamentals of genetic hybrids that offer very little to no benefit to feeding insects and birds.

Time to make a small difference on a global scale and encourage our neighbors friends and families to sow a patchwork quilt of native wildflowers like a blanket to protect our sacred planet!

development and toxic pollution many native wild flowers, and wildlife are under-threat of extinction.

Time to make a small difference on a global scale and encourage our neighbors friends and families to sow a patchwork quilt of native wildflowers like a blanket to protect our sacred planet!

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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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