Sea Holly (Rattlesnake-Master, Sea Holm)
Eryngium species. APIACEAE (UMBELLIFERAE).
Planting and Growing Sea Holly
You’ll find everything you need to know to plant and grow sea holly in the accompanying table’s tabs:
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- Flowers, foliage, and root structure of sea holly
- Plant hardiness and growing conditions for sea holly
- Season of bloom and planting time for sea holly
- When, how deep, and where to plant sea holly
- How to plant sea holly
- Watering, fertilizing, care, and pests or diseases of sea holly
- Landscape and container uses of sea holly
- Comments about sea holly and its features
Growing Sea Holly
Nearly 200 species of bushy, erect, deciduous perennial herbs, 1–6 ft. (30–180 cm) tall. Fleshy, hairy, green, pointed, 3-lobed, deeply cut leaves, to 2 in. (50 mm) long, with gray, white undersides, armed with sharp spines, and forming a circular, radiating base.
Commonly cultivated species include Miss Willmott’s ghost, Eryngium giganteum; Sea Holly, Eryngium maritimum; and rattlesnake-master, Eryngium yuccifolium.
Alpine geranium, Erodium reichardii, shares the common name of sea holly but is an unrelated plant species.
Planting and Care Guide
Blooms
Showy, light blue, yellow green, white, thistlelike flowers, 1–2 in. (25–50 mm) wide, on tall, thick stems above leaflike, spiny bracts, in summer.
Best Climates
Hardy. Self-seeding. Zones 4–9.
Soil Type and Fertility
Moist to dry, well-drained, sandy soil. Fertility: Average–low. 6.5–7.5 pH.
Where and How to Plant
Spring in full sun, 1 ft. (30 cm) apart.
Proper Care
Easy. Keep moist until established; drought tolerant thereafter. Fertilize annually in spring. Avoid transplanting. Propagate by division, seed.
About This Plant
Good choice for accents, barriers, borders, edgings in meadow, natural, rock, seaside gardens. Good for cutting, drying. Invasive. Disease resistant. Slug, snail susceptible.