Beachside Blue, Eryngium Seeds

Beachside Blue Sea Holly Seed

Oversized metallic-blue blooms shimmer across sunny gardens
Heat and drought tolerance simplify summer care
Adaptable roots handle sandy and varied soils
Exceptional texture enriches bouquets and perennial borders

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Key Attributes

Botanical Name

Eryngium planum

Days to maturity

365 Days

Sun

Full Sun

Packet

15 Seeds

Zones 5–9 Check your growing zone

About Beachside Blue, Sea Holly Seed, Sea Holly Seed

A magnet for bees and butterflies, this standout perennial brings bold color and unforgettable texture to bouquets, borders, and feature beds. Its oversized, metallic-blue blooms shimmer in the sunlight, creating a striking display that catches the eye from across the garden. Tough and dependable, it thrives with minimal care, standing strong through heat and dry spells. Adaptable to a wide range of soils—including sandy ground—this long-lasting beauty delivers season after season with little effort. Blue color of plant may vary depending on soil types.

Growing details

Planting

Sow Depth

1/8"

Days to Germination

14–28 days

Germination Type

C60 - Cold Moist 60 Days

In-row plant spacing

18-24"

Plant profile

Life Cycle

Perennial

Hardiness Zone

Zones 5-9

Plant Height

48 inches

Growth Habits

Clumping, Upright

Seed & variety

Seeds Per Ounce

22,000

Color

Blue

Seed Type

Open Pollinated

Before Planting

Give Sea Holly a full-sun site with well-drained soil and good air circulation. Remove perennial weeds, loosen compacted ground, and incorporate modest compost without making the bed overly rich. Prepare a fine, firm seedbed. Plan to cold-moist stratify seed for about 60 days before sowing.

Planting

Sow sea holly outdoors in fall or start indoors according to its germination requirement; many perennial species benefit from a cool period before warmth. Maintain even moisture during germination and provide bright light after emergence. Harden indoor-grown seedlings before planting outdoors. Transplant while young to minimize root disturbance, and thin direct sowings after sturdy true leaves develop.

Watering

Once established, sea holly prefers deep, infrequent watering. Let the surface dry between irrigations, supply extra moisture during extended heat, and avoid keeping the crown continuously wet.

Fertilizer

Fertilize sea holly modestly as new spring growth begins, following soil-test recommendations. Stop after midsummer so late tender growth does not reduce winter hardiness.

Harvesting

Sea Holly is ready for cutting when blooms are well colored and nearly open. Use clean shears and long stems. For seed, leave selected heads until dry, then collect before shattering.

Tips

Mulch sea holly after the ground cools in cold climates, keeping material away from the crown. Remove winter-damaged growth in spring and divide overcrowded plants as needed.

Pests & Diseases

Sea holly may suffer powdery mildew, leaf spots, and crown or root rot, particularly in heavy winter-wet soil. Keep mulch away from the crown and remove infected foliage after flowering. Transplant only healthy seedlings; a softened crown usually cannot be saved and indicates the site needs better drainage.

Sea Holly can attract aphids, thrips, spider mites, Japanese beetles, and slugs. Scout flowers and new growth regularly, handpick when practical, and protect beneficial insects with targeted controls.