Chocolate Cosmos is the sweet nickname of Cosmos atrosanguineus, a delicate but richly colored and scented flower. Vanillin, the same compound that gives vanilla its scent and flavor, is responsible for the distinctive chocolate and vanilla fragrance of this delightful bloom. C. atrosanguineus (Asteraceae family) are herbaceous perennials that grow from fleshy tuberous roots, but these heat-loving plants are only hardy in zones 9 through 11. Gardeners in cooler zones can grow them as a tender annual; under optimal conditions, the plants may produce tuberous roots that can be dug up at the end of the season, to store and replant the next spring.

Unbox your plugs and water them immediately - the plugs cannot be allowed to dry out fully. Harden off for a few days and transplant immediatley, or bump the plugs up into larger cell trays (50 or 72) or into small pots if you cannot plant out right away. Plant out Chocolate Cosmos plugs in the spring, after all threat of frost has passed. They can be planted in full sun at the same time as Zinnias, Celosia, Dahlias, and other heat-loving varieites. It is important to choose a site with loose, well-draining soil of average fertility for the Chocolate Cosmos: the tuberous roots can rot if the soil stays waterlogged, and an excess of nitrogen will cause heavy foliage growth, but very few flowers. These are long-day plants that will bloom from early summer through to your first frost in the fall.

When you transplant the plug plants, space them about 12 inches apart. Once the young plants have a few sets of leaves, pinch the main stem to encourage the side branches to develop. This will give you more blooms later in the season! Keep your young plants watered while they are establishing in the soil, but dont let them remain waterlogged. If you experience long periods of damp or humid conditions, powdery mildrew can affect the plants. Keeping the foliage dry while watering and correct spacing to allow for airflow between the plants will help prevent powdery mildew. Scout regularly for aphids.

Cut the stems deeply to get the longest stems possible for cut flower use, harvesting when the buds are just beginning to open. A deep cut will also encouage the plant to send up more long stems. Place your harvested stems immediately in cool water, and use a floral preservative like FloraLife to acheive a vase life of up to one week.