Cosmos atrosanguineus

Common Name: chocolate cosmos 
Type: Herbaceous perennial
Family: Asteraceae
Native Range: Mexico
Zone: 7 to 9
Height: 2.00 to 3.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: June to September
Bloom Description: Brownish-red
Sun: Full sun
Water: Dry to medium
Maintenance: Medium
Suggested Use: Annual
Flower: Showy
Attracts: Butterflies
Tolerate: Drought


Grow in average, moderately fertile, medium moisture, well-drained soils in full sun. Tolerates dryish soils. Not winter hardy to the St. Louis area where tubers should be lifted in fall (as with dahlias) and stored indoors over winter.

Noteworthy Characteristics

Cosmos atrosanguineus, commonly called chocolate cosmos, is a tuberous-rooted, tender perennial that features brownish-red flowers (to 1.5") with a chocolate scent atop slender 2-3' stems from early summer to fall. Compound, dark green leaves are pinnately divided into ovate to lance-shaped segments. Also commonly called black cosmos.

Genus name comes from the Greek word kosmos meaning beautiful.

Specific epithet means dark blood-red.


No serious insect or disease problems. Rootstocks may rot in wet soils. Not winter hardy to St. Louis.


Borders. Cutting gardens.