Slender cottage-garden annual with finely divided ferny foliage and tall spires of spurred flowers in blue, mauve, pink, or white. The annual cousin of the larger perennial delphinium.
Hardiness ratings
| System | Rating | Temperature range | How to read it |
|---|---|---|---|
| USDA hardiness zone | Zone 2–11 | −45.6 °C to 10 °C | Zones where it can be grown as an annual — not a frost-tolerance rating |
| RHS hardiness rating | H4 | −10 °C to −5 °C | Plant needs at least this level of cold tolerance |
| Canadian plant hardiness zone | Zone 2–9 | −40 °C and warmer | Zones where it can be grown as an annual — not a frost-tolerance rating |
| Australian (ANBG) zone | Zone 1–6 | −15 °C to 15 °C | Zones where it can be grown as an annual — not a frost-tolerance rating |
As a tender annual, Larkspur doesn't overwinter — the zone range shows where the growing season supports it. See the RHS rating for its actual cold tolerance.
Growing notes
- Plant in mid- to back-border positions for cottage-style vertical accent — direct-sow in autumn or earliest spring for summer flowering
- Self-seeds reliably where allowed — historically a cornfield weed across Europe
- Excellent cut flower with long vase life
Pet caution: Larkspur is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.
Categories
Related plants
Cross-check Larkspur against your zones