How to Grow Cleome (Spider Flower)
Cleome hassleriana
Cleome is a half-hardy annual that produces dramatic spidery flower heads from midsummer to first frost. Sow indoors in spring at 21-24C or direct sow after last frost into warm soil. Space 45 cm apart in full sun and well-drained soil. Plants are heat and drought tolerant once established. Pinch tips at 30 cm for bushier growth. No deadheading needed as flowers continue forming on elongating stems. Self-seeds readily in mild climates.
When to Start
Sow indoors 6 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 21°C.
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Growth Stages
Approximate days from start
Care Essentials
- Sparingly. Cleome thrives in lean soil and overfeeding produces foliage at the expense of flowers.
- Dramatic tall annual with spidery flowers from midsummer to frost. Tolerates heat and drought once established. Self-seeds freely.
Growing Conditions
- Min. soil temperature
- 21°C+
- Germination temperature
- 21–27°C
Pet Safety
- Sow indoors
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- Transplant out
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- First harvest
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Spacing & Planting
| Plant spacing | 45 cm |
| Row spacing | 60 cm |
| Sow depth | 0.6 cm |
| Mature height | 120 cm |
| Mature spread | 50 cm |
Space 45 cm apart for tall varieties. Dwarf series like Sparkler can be planted at 30 cm. Good airflow prevents mildew on sticky foliage.
Growing Conditions
| Min. soil temperature | 21°C |
| Germination temperature | 21–27°C |
| Base growth temperature | 10°C |
| Min. daylength to start | 11h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Cleome (Spider Flower)?
- Plant Cleome (Spider Flower) 45cm apart with 60cm between rows.
- When does Cleome (Spider Flower) flower?
- Cleome (Spider Flower) typically flowers approximately 55 days after transplanting.
- Is Cleome (Spider Flower) frost hardy?
- Cleome (Spider Flower) is classified as Half Hardy.
