Blue Glitter sea holly thrives in hot, dry, sun-baked spots where many perennials struggle, and it even handles salty soil. In midsummer it sends up branching silver-blue stems topped with small, spiny, thimble-shaped flowers in an intense metallic blue.
The flower stems reach 2 to 3 feet over a low rosette of blue-green leaves. It blooms quickly, flowers heavily and is a favorite with bees, butterflies and flower arrangers, since the blooms last well both fresh and dried.
What it looks like
Small oval, thimble-like flower heads about ¾ inch long, each surrounded by a star-shaped collar of narrow, spiny bracts, all in intense metallic blue. The flowers are borne in large numbers on much-branched, rigid stems that are also silver-blue. At the base is a low rosette of smooth, blue-green, heart-shaped and toothed leaves about 6 to 8 inches tall and 8 to 12 inches wide. Flower stems rise about 24 to 36 inches tall. At peak bloom the plant looks like a shimmering, open candelabra of blue.
Growing it with lavender
Sea holly loves the same hot sun and dry, lean soil as lavender, and its metallic blue flowers and spiky texture make a striking companion to lavender spikes.
Care
Needs full sun and lean, sandy or gravelly soil with sharp drainage; rich or wet soil makes it flop and rot. Hardy in zones 4 to 8, and very drought and salt tolerant once established. It has a long taproot and dislikes being moved, so plant it where it can stay.
At a glance
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Botanical name: Eryngium planum
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Flower color: Metallic blue
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Foliage: Blue-green
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Growth habit: Low basal rosette with tall branching stems
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Mature size: 24–36 in tall × 8–12 in wide
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USDA hardiness zones: 4–8
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Light: full sun
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Bloom start: Early-July
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Peak bloom: Mid-July
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Bloom pattern: Single Flush
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Deer resistance: Resistant
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Pollinator value: Excellent
Sizes and shipping
One full 72-cell plug tray: 72 young starter plugs of this variety (cells about 1⅓ in. wide × 2½ in. deep), rooted and ready to pot up into quarts or gallons. Best for growers and nurseries. Potted plants and plug trays ship during our live-plant seasons, March 1–May 31 and October 1–November 30; June through September is local pickup only. Plugs, potted plants and trays do not ship to AZ, CA, HI, ID, NV, OR, UT or WA.
Shipping note: Taproot dislikes disturbance; plant promptly and keep from overwatering