Plant Eryngium planum 'Blue Glitter' (sea holly) when you want strong, architectural texture and long-lasting blue color in a hot, bright spot. You will get metallic violet-blue flower heads surrounded by spiny bracts, held on stiff stems that look great in the garden and in fresh or dried arrangements.
Give your plant full sun for the best color and the strongest stems. Choose well-drained soil; sea holly is happiest in leaner, sandy, or gravelly ground where water does not linger. Once established, it handles dry conditions far better than wet feet, especially in winter.
Space plants so air can move through the clump as it matures. Water regularly during the first season while roots settle in, then let the soil dry slightly between soakings. Avoid rich fertilizer, which can lead to softer growth and flopping. If you are cutting for bouquets, harvest stems when the heads are well formed but before they fully open.
Leave some stems for winter interest, then cut back old growth as new shoots appear. With its spiky form and bee-friendly blooms, 'Blue Glitter' adds striking contrast among softer perennials and grasses in borders and xeric-style plantings.