How to Grow Clarkia
Clarkia amoena
Clarkia is a hardy annual producing elegant satin-textured flowers in shades of pink, purple, and white on upright stems through summer. Direct sow in spring or autumn in full sun and poor to average, well-drained soil. Thin seedlings to 20 cm. Pinch tips at 15 cm for bushier plants. Deadhead regularly for a longer display, or leave to self-seed. Excellent cut flower with good vase life.
When to Start
Direct sow outdoors as soon as soil reaches 7°C — typically early to mid spring. Hardy enough to tolerate light frosts.
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Growth Stages
Approximate days from start
Care Essentials
- Rarely needed. Thrives in poor to average, well-drained soil. Rich soil encourages leggy growth with fewer flowers.
- One of the easiest hardy annuals. Direct sow where it is to flower as it dislikes root disturbance. Succession sow every 3 weeks for continuous blooms. Excellent cut flower.
Growing Conditions
- Min. soil temperature
- 7°C+
- Germination temperature
- 15–21°C
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- Direct sow
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- First harvest
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Spacing & Planting
| Plant spacing | 20 cm |
| Row spacing | 30 cm |
| Sow depth | 0.3 cm |
| Mature height | 60 cm |
| Mature spread | 25 cm |
Direct sow and thin to final spacing. Clarkia resents root disturbance and transplants poorly. Close spacing provides mutual stem support.
Growing Conditions
| Min. soil temperature | 7°C |
| Germination temperature | 15–21°C |
| Base growth temperature | 5°C |
| Min. daylength to start | 10h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Clarkia?
- Plant Clarkia 20cm apart with 30cm between rows.
- When does Clarkia flower?
- Clarkia typically flowers approximately 75 days after transplanting.
- Is Clarkia frost hardy?
- Clarkia is classified as Hardy.
