Cosmos 'Rubenza' Seeds
Cosmos bipinnatus ‘rubenza’
Cosmos bipinnatus ‘Rubenza’ is a standout half-hardy annual with rich, velvety crimson flowers that soften to warm rose tones as they mature, creating a beautiful two-tone effect. With finely divided, ferny foliage and upright stems reaching around 70–75 cm, it’s ideal for cut-flower beds, borders and containers. Thriving in full sun and well-drained soil, this Cosmos variety flowers reliably through summer and early autumn and is loved by pollinators.
Approx 40 seeds
- Cut Flowers
- Pollinator-Friendly
- Pot Fans
- Fuss Free
Cosmos 'Rubenza' Seeds – Quick Growing Guide
Cosmos ‘Rubenza’ is a compact, pollinator-friendly cut flower with dark crimson blooms that fade to soft pink. Easy to grow from seed, it thrives in full sun, flowers all summer, and usually doesn’t need staking in sheltered gardens — perfect for borders, pots and cutting gardens.
How to Sow, Grow and Harvest Cosmos 'Rubenza' Seeds
- Sow:March–September, direct outdoors or in pots
- Germination:7-14 days
- Grow:Full sun, well-drained soil, space plants 15–20 cm apart
- Water:Keep soil lightly moist; avoid waterlogging
- Harvest:Cut stems as buds begin to open for longest vase life
- Best for:Pots, borders, cut-flower beds
Rubenza brings drama without fuss. Its deep, wine-red blooms feel contemporary yet romantic, and the naturally sturdy, compact habit means it rarely needs staking in sheltered spots. It’s long-flowering, pollinator-friendly, brilliant in a vase, and looks incredible planted en masse or mixed with softer pastels.
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Grow in Your Garden
Calendar
How to Grow
Cosmos 'Rubenza' seeds can be sown indoors from March or directly outdoors after the last frost, thriving best in full sun with well-drained soil. Starting them in pots allows for a head start before transplanting to balconies, containers, or garden beds.
Sowing
Sow one seed per hole on firm, damp soil and cover lightly, ensuring they remain in full sun to aid germination. Sow between March and June for optimal results.
Growing
Thin seedlings to 30–40cm apart to support their tall, airy growth and prevent overcrowding, suitable for the recommended 40cm pot size. This spacing encourages strong, upright plants that flourish from June through October.
Plant care
Water regularly during dry spells but avoid overfeeding to prevent excessive leafy growth at the expense of blooms. Pinch out growing tips when plants reach 20–25cm to promote bushier plants and deadhead frequently to encourage continuous flowering into autumn; tall stems may require staking in windy conditions.
About Cosmos 'Rubenza'
Cosmos bipinnatus ‘Rubenza’ is an easy, rewarding annual with rich, velvety red blooms that soften to dusky pink as they age. Ideal for borders and large pots, it flowers freely through summer, attracts bees and butterflies, and is one of the most reliable cut flowers for long-stemmed picking. A perfect choice for beginners and seasoned gardeners alike.
- Cut Flowers
- Pollinator-Friendly
- Pot Fans
- Fuss Free
Eventual height & spread
History of Cosmos 'Rubenza'
The name 'Cosmos' comes from the Greek word for 'ordered universe', inspired by the flower’s perfectly arranged petals. Historically cultivated in Spanish mission gardens, these flowers bring harmony and beauty to your garden.
| Other Names | Garden cosmos and Mexican aster. |
|---|---|
| Pet/Baby Safe | Non-toxic |
FAQs
Yes. Cosmos Rubenza is very easy to grow from seed and ideal for beginners. Sow directly outdoors or into pots, keep the soil lightly moist, and it will flower reliably throughout summer with minimal care.
Sow Cosmos Rubenza seeds from March to September. Earlier sowings can be started indoors, while later sowings work well direct outdoors once the soil has warmed.
Yes. Cosmos bipinnatus ‘Rubenza’ is highly attractive to bees, butterflies, and other pollinators, making it an excellent choice for wildlife-friendly and pollinator gardens.
Absolutely. Cosmos Rubenza produces long, straight stems with rich red blooms that are perfect for cutting. Harvest flowers just as the buds begin to open for the longest vase life.