Photo Credit: Lynne Resch of Fleurs du Bien, who grew Cosmos 'New Choco' from Farmer Bailey plugs.
| Common Name | chocolate cosmos |
| Genus | Cosmos |
| Species | C. Atrosanguineus |
| Family | Asteraceae |
| Life Cycle | Herbaceous perennial with fleshy tuberous roots. |
| Plug Care | Do not allow to dry out fully, harden off and plant, or bump up soon after receiving plugs. |
| Netting / Staking | Not absolutely necessary, one layer of netting may help keep stems straight in windy areas. |
| Temperature Range | Chocolate cosmos are heat loving plants and are only hardy in zones 9-11. |
| Spacing | 12" |
| Soil Preference | Loose, well draining soil with average fertility. An excess of nutrients will cause heavy foliage growth with few flowers. The tuberous roots are at risk of rotting if the soil isn't free-draining. Neutral to slightly acid pH is best. |
| Day Length | Long day plants - will bloom readily from early summer through to frost. Plant in full sun. |
| Pinching | One or two pinches while the plants are young will encourage vigorous side branching and more blooms later in the season. |
| When to Plant | Plant in the spring after all threat of frost has passed. |
| Harvesting | Harvest when buds are beginning to open. Cut deep to get the longest stem possible and to encourage the plant to send up more long stems. |
| Post Harvest Care | Cut stems should immediately be placed into cool water. With the use of a floral preservative expect a vase life of around a week. |
| Diseases / Insects | Powdery mildew can set in during long periods of damp conditions, or at the end of the season when spores are more prevalent in the environment. Keep the foliage dry while irrigating and spacing the plants to allow for more air flow to help prevent this. Watch closely for aphids, which may attack this crop. |
| Bailey's Notes |
Chocolate cosmos are often grown for their fragrance which is often described as a sweet chocolate/vanilla scent. This is due to the plant producing a compound called vanillin - the same compound found in the vanilla bean. The scent may be stronger toward the end of the day. Under optimal growing conditions these plants *may* produce tubers by the end of the season that can be dug and stored over the winter, similarly to dahlia tubers. While this is true for wild-type chocolate cosmos, newer cultivars were likely bred with other characteristics in mind and may not be the strongest tuber producers. |