Eryngium - Key Growing Information

Eryngium planum cultivars of two types, the white and blue flat sea hollies, with their silvery thistle-like heads.
DAYS TO GERMINATION: 7-10 days at 72-75°F (22-24°C).

SOWING: Transplant (recommended): Sow 10-16 weeks before planting out. Do not cover as light is required for germination. Bottom water or mist lightly to avoid covering the seeds with displaced soil. Transplant into cell packs or 2-4" containers 5-8 weeks after emergence. Harden off and transplant outside after the last frost.

GROWING ON: Grow at 55-60°F (13-16°C) and avoid temperatures above 70°F (21°C).


SOIL REQUIREMENTS: Dry, sandy soil, but will tolerate saline soil conditions. Eryngium is sensitive to overwatering.

PLANT SPACING: 18-24". Clumps spread slowly and can remain undisturbed indefinitely.


HARVEST: Fresh or dried: Cut when the entire flower head and bracts turn blue or white, depending on the cultivar. Can be hung to air dry, or dry in desiccant to preserve more color.

USES: Excellent fresh cut or dried flower. For midborder in perennial beds.

SCIENTIFIC NAME: Eryngium planum

ALTERNATE NAMES: Plains eryngo, flat sea holly