Sea holly (Eryngium planum 'White Glitter')
Eryngium planum 'White Glitter' sea holly offers unique, silvery-white, thistle-like blooms. A low maintenance, drought-tolerant perennial perfect for sunny borders.
Complete Plant Information
Overview
Eryngium planum ‘White Glitter’, commonly known as sea holly, is a distinctive herbaceous perennial celebrated for its unusual, architectural flowers. Unlike its common blue relatives, ‘White Glitter’ presents spiny, egg-shaped flower heads of a glittering white hue, held aloft on silver-green stems throughout the summer months. This plant introduces exceptional texture and long-lasting color to mixed borders and xeriscapes where many traditional perennials struggle.
Valued for its low maintenance needs and impressive durability, this variety thrives in the harshest conditions, provided it receives adequate sunlight. Its unique structure makes it an excellent choice for gardeners seeking architectural elements or striking material for dried arrangements once the season concludes. The visual appeal of Eryngium planum ‘White Glitter’ is undeniable, offering a sharp contrast against softer foliage.
Once established, this sea holly becomes exceptionally drought-tolerant, rewarding patient gardeners with minimal upkeep. Its taprooted nature means it firmly anchors itself, offering reliable performance year after year in suitable, well-drained soil environments.
Fast Facts
- Plant Family: Apiaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 5-8
- Size at Maturity:
- Height: 2-2.5 ft
- Spread: 1-1.5 ft
- Bloom Time: June to September
- Bloom Description: White
- Sun Exposure: Full sun
- Water Needs: Dry
- Maintenance Level: Low
How to Grow
Plant Eryngium planum ‘White Glitter’ in spring or early fall after the danger of hard frost has passed, ensuring it settles before extreme temperatures arrive. The key to success is location: choose a spot offering full sun exposure and soil that is sandy, dry, and extremely well-drained. This plant tolerates poor soils readily, but rich, overly fertile ground can encourage flopping, disrupting the pleasing mound shape of the sea holly.
Maintenance for established Eryngium planum ‘White Glitter’ is minimal. Water sparingly; this plant demands dry soil conditions and is highly susceptible to fatal root rot if overwatered. Fertilization is generally unnecessary, as lean soil supports better stem strength. Monitor for sprawling if the planting site receives afternoon shade or overly rich amendments.
Because it is a deep taprooted plant, sea holly transplants poorly once mature, so confirm its permanent location immediately after purchase. While perennials generally spread slowly, avoid disturbing the established root zone to maintain vigor. Early season cleanup involves removing old foliage, though some gardeners leave stems standing for winter interest or seed collection if desired. Notably, ‘White Glitter’ may flower the first year when started directly from seed.
Landscape Uses
The unique structure and bright white blooms of Eryngium planum ‘White Glitter’ make it a stellar choice for areas receiving intense, prolonged summer heat. It excels in sun-baked landscapes where less resilient plants wilt, establishing strong vertical accents in beds and borders. Whether used as a bold single specimen to capture attention or grouped for a textural mass planting, this sea holly performs admirably.
This plant’s sturdy habit and striking flower heads provide superb material for floral work. Harvest stems when the flower heads are fully developed but still firm for excellent results in fresh bouquets or dried arrangements. Group Eryngium planum ‘White Glitter’ alongside companions that share its love for dry conditions, such as ornamental grasses, lavender, or sedums, ensuring cultural needs align across the border design. It also proves surprisingly effective when incorporated into combination containers, adding a spiky, architectural element.
Standout Features
Flower Qualities
- Showy
- Good Cut
- Good Dried
Noteworthy Characteristics
Eryngium planum, commonly called sea holly, is a coarse, clump-forming perennial that features a summer bloom of steel-blue, thistle-like flower heads on branched stems rising from a rosette of dark green basal leaves. Basal leaves (typically elliptic to oblong, cordate-based and deeply-toothed) form a rosette to 6” tall and to 14” wide. Stiff, branched, violet-blue stems (to 32” tall), bearing abundant, egg-shaped, thistle-like, violet-blue flower heads, rise from each basal rosette in summer. Each flower head is a spherical-cylindrical umbel that is packed with tiny, stemless, violet-blue flowers. Each flower head is subtended by a narrow, spiky collar of spiny, blue-green bracts. Summer bloom is often profuse.Genus name comes from an ancient Greek name used by Theophrastus for a plant which grew in Greece (probably Eryngium campestre) or is a Greek reference to the prickly or spiny nature of plants in this genus.Specific epithet means flat.‘White Glitter’ typically rises in a globular mound to 2-2 1/2’ tall. Spiny, egg-shaped, “glittering” white flower heads bloom abundantly throughout summer atop silver-green stems.
Tolerances
- Drought
- Dry Soil
Potential Problems
Eryngium planum ‘White Glitter’ generally avoids serious insect or disease issues, particularly when sited correctly. The primary management concern is drainage; the plant is highly susceptible to root rot if soils remain wet or heavy. Ensure soil conditions are dry, especially heading into winter.
While generally resistant, environmental stresses can sometimes invite minor pests. Watch carefully for leaf spot diseases, which are more likely to appear in periods of high humidity or if overhead watering occurs. Slugs and snails may also target tender new growth early in the season. Addressing slugs proactively, or ensuring highly porous soil, minimizes these late-season nuisances.
Frequently Asked Questions
What hardiness zones is Sea holly suitable for?
The Eryngium planum ‘White Glitter’ sea holly is ideally suited for USDA Hardiness Zones 5 through 8.
How large does Sea holly grow?
This herbaceous perennial typically reaches a height between 2 and 2.5 feet tall, spreading modestly between 1 and 1.5 feet wide at maturity.
When does Sea holly bloom?
Eryngium planum ‘White Glitter’ offers its signature bloom time from June through September, featuring unique white flower heads.
What sun exposure does Sea holly need?
For the best performance and strongest stems, Eryngium planum ‘White Glitter’ requires full sun exposure throughout the day.
Conclusion
The architectural form and sparkling white blooms establish Eryngium planum ‘White Glitter’ as an indispensable plant for demanding, sunny sites. Its superior drought tolerance and low maintenance profile make this sea holly a reliable, structural anchor in any perennial garden design. Before planting, confirm your location falls within USDA Zones 5-8 and ensure the soil dries rapidly between watering events.
Companion Planting
When selecting partners for Eryngium planum ‘White Glitter’, prioritize plants that thrive in full sun and dry, lean soil conditions. Avoid moisture-loving companions that might increase humidity around the base of the sea holly, leading to rot issues. Excellent partners include Mediterranean natives such as Russian Sage (Perovskia atriplicifolia), various Sedums, and Ornamental Grasses like Blue Fescue (Festuca glauca).
These companions share the required cultural profile, allowing you to create beautiful textural contrasts without risking plant health. The spiky structure of the sea holly pairs wonderfully against the fine texture of many drought-tolerant ornamental grasses, providing year-round interest even when the Eryngium planum ‘White Glitter’ is not in bloom.
Propagation Tips
Propagating Eryngium planum ‘White Glitter’ is best achieved through direct seeding or carefully managed division, though division is less successful due to the plant’s deep taproot system. If starting from scratch, sowing seeds directly into the garden bed in early spring after the last frost is recommended; successful germination results in plants that may bloom the very first year.
For mature plants, division requires diligence. Attempt this only in early spring before new growth is extensive, working to disturb the central crown as little as possible while trying to capture a section with its own established taproot. Because transplant shock is common, ensure any moved plants are given maximum attention to drainage immediately following relocation.
