Cosmos Rubenza

Cosmos Rubenza (Cosmos bipinnatus) is an eye-catching annual prized for its large, velvety blooms that open in deep ruby red and fade gracefully to antique rose shades. This colour-changing effect adds depth and interest to both garden beds and floral arrangements. With its tall, airy stems and fern-like foliage, ‘Rubenza’ is ideal for mixed borders, cottage gardens, and as a feature in cutting gardens. Its upright habit and long flowering period make it especially valuable in summer displays.

As a cut flower, ‘Rubenza’ performs exceptionally well, offering long, slender stems and good vase life. Regular harvesting encourages more blooms, extending the flowering season right into autumn.

Home gardeners will find Cosmos relatively easy to grow from seed. These drought-tolerant annuals are low-maintenance, making them suitable for beginner gardeners seeking effortless beauty.

Transplant is recommended. Start seeds indoors 5–7 weeks before the last frost date. Sow into preferred seedling container and harden off seedlings 5-7 weeks later, planting out after the danger of frost has passed. Seeds can also be sown directly into well-drained soil after the danger of frost has passed.

Cosmos prefers full sun and thrives in average to poor soil without excessive fertilisation, which can cause more foliage than blooms. Plant out seedlings with sufficient space to grow, or thin seedlings if direct sown. Pinching is recommended to encourage branching and deadhead regularly to prolong blooming.