Is this plant a perennial?

It is technically a short lived perennial that often dies after setting seed.

Does it need full sun?

Yes, it thrives in full sun to perform its best.

Plant guide

Miss Willmott's Ghost.

Eryngium giganteum

Pronounced eh-RIN-jee-um jy-GAN-tee-um

Also known as Miss Willmot's-ghost, Miss Willmott's Ghost, Tall Eryngo, giant sea holly, giant sea-holly

Miss Willmott's Ghost — Photo by Татьяна Максимова (CC BY) via iNaturalist

This striking biennial brings a silvery, architectural look to your garden. It is famous for the way its bracts seem to glow in the moonlight. You will love how it adds a touch of mystery to any sunny border.

Another photo of Miss Willmott's Ghost — Photo by John T (CC0) via gbif

At a glance

Care level: Easy
Plant type: Biennial
Light: Full sun
Indoor light: Direct sun
Water: Every 7 to 14 days
Mature size: 3 to 4 feet
Growth rate: Medium
Hardiness: USDA 4 to 8
Bloom time: Early to late summer

Care

Plant this in a spot with plenty of sun and well draining soil. Watch for wilting if the soil stays too dry, but avoid overwatering to prevent root rot. It often self seeds, so let the flowers dry if you want more plants next year.

Watering: Water deeply once the top inch of soil feels dry to the touch.
Feeding: A light application of balanced compost in early spring is plenty.
Pruning: Cut back the dead flower stalks in late autumn or early spring.
Repotting: Since it is a biennial, you will likely only need to move it once before it finishes its life cycle.
Soil: Sandy or gritty, well draining soil
Soil pH: Neutral to slightly alkaline
Temperature: -20 to 30°C
Humidity: 40 to 60%
Drought tolerance: High
Lifespan: Short lived perennial, typically 2 to 3 years.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes
Stunted growth during the active season

Safety

People: The plant contains compounds that can cause mild skin irritation upon contact.
Children: The sharp, spiny foliage poses a physical injury risk to small children if handled.
Contact allergens: Handling the sharp, spiny leaves can cause mechanical skin irritation.
Airborne allergens: There are no significant reports of airborne allergens for this species.
Edibility: This plant is not considered edible and may cause stomach upset if ingested.

How to identify it

Silvery heart shaped bracts
Spiky, thistle like flower heads
Sturdy, branched stems
Toothed, grey green basal leaves

Height: 0.6 to 1.2m
Spread: 0.3 to 0.45m
Leaves: green, silver, deciduous
Flowers: silver, blue, 3 to 6cm
Fruit: brown, Autumn

Problems to watch for

By symptom

Plant problems by symptom

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Growing it

Propagation: seed
When to plant: spring, autumn
Overwintering: Leave the dried flower heads standing for winter interest and to allow for natural self seeding. Cut back the dead foliage in early spring before new growth appears.
In containers: It can grow in large containers, but the deep taproot prefers the ground.

Seed Sowing

Collect seeds in late autumn once the heads turn brown.
Sow seeds directly into the garden in a sunny spot.
Ensure the soil is well drained to prevent winter rot.

Plant in groups of three or five to create a dramatic architectural statement in the border.

Grows well with

Lavender · They share similar requirements for sun and well drained soil.
Sedum · The succulent foliage contrasts beautifully with the spiky flowers.
Russian Sage · Both plants provide a airy, silver aesthetic to the garden.

Similar species

Sea Holly · It is a coastal relative with similar blue, spiky flower heads.
Flat Sea Holly · It features smaller, more numerous blue flowers.

Science

Family: Apiaceae
Genus: Eryngium
Order: Apiales
Class: Magnoliopsida
Native range: Caucasus region
Conservation: This species is not of conservation concern and is widely cultivated.

It thrives in rocky, well drained soils where its deep taproot can access moisture.

Value to wildlife: nectar source, winter seed source for birds
Pollinators: bees, butterflies, moths
Uses: ornamental border, dried flower arrangements, pollinator garden

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 8/9
Temperature: 5/9
Moisture: 3/9
Nutrients: 3/9

Taxonomy resolved against GBIF.

Questions people ask

Is this plant a perennial?: It is technically a short lived perennial that often dies after setting seed.
Does it need full sun?: Yes, it thrives in full sun to perform its best.

Where the name comes from

The genus name comes from the Greek word for a type of thistle, while the species name refers to its large size.

Good to know

It is a short lived perennial that often acts like a biennial.
The plant is famous for self seeding freely in the garden.
It was named after Ellen Willmott, who allegedly scattered seeds in gardens she visited.

Also in

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.