Chocolate cosmos (Cosmos atrosanguineus) is a captivating and unique flowering plant that delights gardeners and plant enthusiasts alike. Named for its rich, dark maroon flowers that emit a delightful chocolate scent, this plant is a charming addition to any garden. Originating from Mexico, chocolate cosmos has found its way into gardens worldwide, including those in the UK.

Characteristics

Chocolate cosmos is a herbaceous perennial that typically grows to a height of 40-60 cm. Its most distinctive feature is its striking flowers, which appear almost black and have a velvety texture. These blooms, which appear from midsummer to early autumn, exude a sweet, chocolate-like fragrance, making them a favorite among gardeners and pollinators.

The plant has a clump-forming habit, with slender stems and pinnate leaves that provide a delicate backdrop to its dramatic flowers. Its tuberous roots are key to its survival and regrowth, storing nutrients that allow the plant to return year after year.

Growing and Caring for Chocolate Cosmos

Chocolate cosmos thrives in well-drained soil and prefers a sunny position, although it can tolerate partial shade. Here are some key tips for growing and caring for this unique plant:

1. Planting: Plant chocolate cosmos tubers in spring after the last frost. Space the tubers about 30 cm apart and cover them with soil, ensuring the growing point is just below the surface.
2. Watering: Keep the soil consistently moist but not waterlogged. During dry spells, regular watering is essential to support healthy growth and abundant flowering.
3. Feeding: A balanced, slow-release fertilizer applied in the spring can provide the necessary nutrients for vigorous growth and flowering.
4. Deadheading: Regularly remove spent flowers to encourage continuous blooming and maintain a tidy appearance.
5. Winter Care: In regions with mild winters, chocolate cosmos can survive in the ground with a thick mulch layer to protect the tubers from frost. However, in colder climates, it’s advisable to lift and store the tubers indoors over winter.

Will Chocolate Cosmos Return the Following Year?

Chocolate cosmos is a perennial plant, meaning it can return year after year under the right conditions. The key to its perennial nature lies in its tuberous roots, which store energy and nutrients. However, whether it will return the following year depends largely on winter care and the local climate.

In milder regions, where the ground does not freeze deeply, chocolate cosmos can remain in the ground and emerge in the spring. Applying a thick mulch layer can provide additional protection against cold temperatures. In colder climates, where severe frosts are common, the tubers are at risk of freezing and rotting. To ensure the plant’s survival, it’s best to lift the tubers in the autumn before the first frost. Here’s how to do it:

1. Lifting the Tubers: Carefully dig up the tubers, being gentle to avoid damage. Brush off excess soil.
2. Drying: Allow the tubers to dry in a cool, airy place for a few days.
3. Storage: Store the tubers in a container filled with peat moss, vermiculite, or sand. Keep the container in a cool, dark place where the temperature remains above freezing, typically between 4-10°C.
4. Replanting: Replant the tubers in the spring after the danger of frost has passed.

Conclusion

Chocolate cosmos is a stunning and aromatic addition to any garden, offering both visual appeal and a delightful scent. While it is a perennial plant, its ability to return year after year depends on proper care and protection, especially during the winter months. By following the recommended growing and wintering practices, you can enjoy the beauty and fragrance of chocolate cosmos for many seasons to come. Whether left in the ground in milder climates or lifted and stored in colder ones, chocolate cosmos will reward careful gardeners with its unique and captivating blooms.