Zone 4 · Sea Holly

Planting Sea Holly in Zone 4

Eryngium planum

✅ Sea Holly thrives in zone 4 (hardy 4–9)

Can I plant today?

Last frost is in 4 weeks. Wait until soil warms.

Evaluated for April 27, 2026 ·

Zone's last frost

around May 15

Zone's first frost

around September 15

Bloom window

July – September

Peak bloom

August

Sun required

full sun

Mature height

36"

Spacing

18" apart

Type

perennial

How to plant Sea Holly in zone 4

Plant in spring in dry, well-drained soil. Steel-blue bracts are striking fresh or dried.

Sea Holly peaks in August. These companions keep your bed in color before and after.

Shasta Daisy

Peaks in July

Purple Coneflower

Peaks in July

Salvia

Peaks in June

Tulip

Peaks in April

Want a full bed designed for zone 4?