Biennial sea holly with silver-white spiny bracts surrounding pale steely-blue thimble-shaped flower heads. Whole plant takes on a ghostly luminous quality in midsummer.
Hardiness ratings
| System | Rating | Temperature range | How to read it |
|---|---|---|---|
| USDA hardiness zone | Zone 4–8 | −34.4 °C to −6.7 °C | Plant tolerates down to this zone |
| RHS hardiness rating | H6 | −20 °C to −15 °C | Plant needs at least this level of cold tolerance |
| Canadian plant hardiness zone | Zone 4–8 | −29 °C to −1 °C | Plant tolerates down to this zone |
| Australian (ANBG) zone | Zone 1–5 | −15 °C to 10 °C | Plant tolerates down to this zone |
Growing notes
- Flowers July — a striking midsummer marker, the silver bracts catch low evening light
- Strictly biennial — sow successive years and allow self-seeding to perpetuate
- Named for Edwardian gardener Ellen Willmott, said to scatter its seed in other gardens she visited
- Drought tolerant and salt tolerant — excellent for coastal and gravel gardens
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Related plants
Cross-check Miss Willmott’s ghost against your zones