Apiaceae, native to Europe and Asia.

Germination: Both species are best sown indoors at a depth of 4 times the size of the seeds. Prechill E. bourgatii at 40° for 2 months, then sow at 40°. Expect germination in 12-20 days. No need to prechill E. planum; sow it at 68-70° and expect germination in 10-15 days. Both species can be sown outdoors in early spring through summer, up to two months before first frost.

Growth: Transplant when there are at least two sets of true leaves. Despite the weaponry of spines, a few pests and diseases are bold enough to infect the Sea Hollies: namely root rot, slugs, and powdery mildew. Protect from excess moisture in winter and mulch when dormant. Their strengths are numerous: drought and salt tolerances are high and they thrive in dry, sandy, poor soils. Plant in full sun and prune to keep the plants tidy.

Appearance and Use: They add blue flower and leaf color and spiky texture to a border or wildflower garden. Flowers cut well for use both fresh and dried. Eryngium bourgatii grows 1-2 feet tall with blue-green palmate leaves with spiny teeth and a display of striking white leaf veins. The round flower head of small, silvery blue flowers sits atop spiny, silver bracts. As a whole, this plant makes quite a fearsome impact. Eryngium planum is very similar, but larger in habit, to 3 feet, and generally less fearsome. The basal leaves are heart-shaped and bear no spines.