Cosmos atrosanguineus – Chocolate Cosmos, Fragrant Dark Flowers

Chocolate Cosmos (Cosmos atrosanguineus)

Cosmos atrosanguineus (KOZ-mose at-tro-san-GWIN-ee-us) produces dark red-brown, sometimes almost black, velvety flowers on long, slender, reddish-brown stems from early summer to autumn. A chocolate-scented flower! This tuberous-rooted, tender perennial native to Mexico can be overwintered indoors where not hardy. Grow in a border or containers where flowers can be appreciated up close. They also make good cut flowers. Synonym: Bidens atrosanguinea.

Noteworthy Characteristics

• Chocolate fragrance
• Dark, almost black flowers over a long period
• Good cut flower

Growing Conditions & Care

Grow in moist but well-drained, fertile soil in full sun. Deadhead and provide support. Mulch in autumn where hardy, or lift tubers and keep frost-free during winter, storing in barely moist peat.

Propagation

Root basal cuttings with bottom heat in early spring.

Potential Problems

Stem canker, powdery mildew, Rhizoctonia stem rot, gray mold, and aphids sometimes cause problems.

Quick Reference

• Height/Spread: 1–3 ft.
• Light: Full sun only
• Moisture: Dry to medium
• Maintenance: Moderate
• Bloom Time: Summer to fall
• Flower Color: Brown, Red
• Uses: Beds, borders, cottage gardens, containers, cut flowers
• Type: Perennial