Overview
Cosmos sulphureus, yellow cosmos or sulphur cosmos, is a fast-growing annual in the aster family, reaching 2-6 feet (60-180 cm) tall and 1-2 feet (30-60 cm) wide. Its stems carry finely divided, fern-like leaves and branch freely toward the top. From summer until frost it produces daisy-like flower heads 1.5-2.5 inches (4-6 cm) across in yellow, gold, and orange, each with a ring of toothed ray florets around a yellow-orange center. The plant grows quickly from seed, flowers within two to three months, and self-sows freely where the ground is bare. Native to Mexico and Central America, it has naturalized across warm regions worldwide and is listed as invasive in parts of the southeastern United States and elsewhere. It tolerates heat, drought, and poor soil but flops or grows leggy in rich soil or shade. C. sulphureus is grown in annual borders, cutting gardens, and pollinator plantings, and its open flowers draw bees and butterflies.
Native Range
Cosmos sulphureus is native to Mexico and Central America, extending into northern South America. It grows on disturbed ground, roadsides, and open fields in warm climates. It has naturalized widely across the southern United States, Asia, Africa, and Australia.Suggested Uses
Yellow cosmos is grown in annual and mixed borders, cottage and cutting gardens, and pollinator plantings. Its flowers draw bees, butterflies, and other insects, and the seeds feed finches and other birds. It is used as a quick filler and for naturalized meadow color in warm regions.How to Identify
Appearance
Size & Dimensions
Height2' - 6'
Width/Spread1' - 2'
Bloom Information
Detailed Descriptions
Flower Description
Yellow, gold, and orangeFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
Grow yellow cosmos in full sun in average to poor, well-drained soil. Sow seed directly after the last frost, or start indoors four to six weeks earlier; seedlings grow quickly and flower in two to three months. Lean soil and full sun keep plants compact and flowering, while rich soil and shade cause tall, floppy growth with fewer blooms. Water is needed only during extended drought, as established plants are heat- and drought-tolerant. It is grown as an annual in all zones and dies at frost, but it self-sows and returns from seed. It has few pests, though aphids and powdery mildew can appear in crowded plantings.Pruning
Pinch young plants to encourage branching and more flowers. Deadhead spent blooms through the season to prolong flowering. Cut plants back if they grow leggy in midsummer to bring on fresh growth.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summer
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons
✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
both
Indoor Start
5 weeks before last frost
Direct Sow Timing
After last spring frost
Days to Maturity
60–90 days
Plant Spacing
12 inches