Blue Glitter Sea Holly

Overview

• Botanical name: *Eryngium planum ‘Blue Glitter’. 

• Common name: Sea Holly ‘Blue Glitter’

• Habit: Upright spires of steel‑blue flower heads and bracts on silvery stems, above basal rosette of blue‑green toothed leaves. 

• Size: Typically about 70‑90 cm tall (≈ 28‑35″) and 40‑60 cm wide (≈ 16‑24″) according to one grower. 

• Soil/Light preferences: Very drought tolerant once established; thrives in full sun, very well‑drained, lean to average soils.

• Hardiness & conditions: Rated for Zones 4‑8 in one source. 

• Landscape/feature uses: Excellent for dramatic texture, cut flowers, dried arrangements, pollinator friendly. 

Light & Site Requirements

• Sun: Full sun (at least 6 hrs direct light) is strongly recommended. The more sun, the more intense the blue colour. 

• Soil: Extremely well‑drained soil is essential. Sandy, gritty or rock‑garden types are ideal. Avoid heavy clay or overly rich, moist soils. 

• Moisture: Very low water once established; the plant resent overwatering. Good for dry sites, poor soils. 

Planting & Maintenance

• Planting: Choose a permanent spot; sea holly doesn’t like being moved because of its tap‑root. 

• Watering: Water regularly during the first season until established. Thereafter, minimal watering — only during extended dry spells. Avoid water‑logging. 

• Fertilising: Minimal feeding is better. Rich soils may cause the plant to become floppy or lose its upright form. 

• Dead‑heading/Pruning: You can remove spent flowers for tidiness; the seed‑heads also provide interest. 

• Division/Transplanting: Not recommended often due to tap‑root. Only divide if necessary and carefully. 

Cold‑Climate / Zone 3 Considerations

• Although most sources list hardiness to Zone 4, with excellent site conditions (very well‑drained, full sun, not in heavy winter‑wet soils) it may perform in cooler climates with care.

• For a colder zone: ensure the crown stays dry in winter/spring melt, avoid low spots where water accumulates, choose a sunny slope or well‑raised bed.

• Its drought‑tolerant nature is a plus in harsh climates, but the key is drainage and sun rather than fertile soils or moisture.

• Because the form is upright and architectural, even winter‑leafless stems or dried flower heads provide structure in the garden.

Photo from gardenia.net