Sea Holly

Sea Holly (Eryngium) is a highly distinctive genus that includes plants with some of the most unusual forms and colors to be found in any garden. These perennials produce low rosettes of stiff, spiny leaves that provide a base for branching, nearly bare stems that are capped by thimble-shaped flower heads framed by a ruff of spiky bracts, the entire plant appearing in otherworldly shades of blue, greenish white, or silver. The unique, sculptural quality of Sea Holly has made it a favorite of floral designers. We love it in prominent spots in mixed sunny borders where the plants provide contrasting form and color for a wide variety of plants including Allium ‘Millenium,’ Allium sphaerocephalon, Echinacea (Coneflower), Liatris, and Ornamental Grasses. The trick to succeeding with Eryngiums is to plant them in full sun and extremely well-draining, low-nutrient soil. (They don’t like mulch or compost-rich soil.) They also benefit from good air circulation. Established plants are tolerant of some drought.