Sulphur Cosmos brings the warm, golden charm of calendula into a cosmos form that's strikingly easy to grow. These bushy annuals reach 4 feet tall and 3 feet wide, blooming within 90 days of planting in warm soil. Hardy in zones 9-11 and frost-tender elsewhere, they thrive in full sun and handle drought beautifully, making them a carefree choice for gardeners who want reliable color without constant fussing.
Full Sun
Moderate
9-11
48in H x 36in W
—
Low
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Lacy, fine-textured foliage forms a gorgeous rounded mound by late summer, crowned with flat golden blooms that echo calendula's warm hues. These cosmos are remarkably drought-tolerant and disease-resistant, thriving in the kind of semi-neglected spots where other plants struggle. The robust, green feathery foliage suggests a plant built for dry conditions, yet it pairs visually with taller companions like Spider Flower without overwhelming them.
Sulphur Cosmos flowers brighten garden beds and borders with their golden tones. Their lacy foliage and bushy habit make them excellent for creating texture and fullness in mixed plantings, while their drought tolerance suits them to naturalized areas and low-water gardens.
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Sow seeds indoors 6-8 weeks before your last frost date, pressing them lightly into soil without covering them completely. Keep soil warmth between 60 and 75 degrees Fahrenheit for reliable germination. Transplant seedlings outdoors after hardening them off once nighttime temperatures stay above 50 degrees.
Transplant hardened-off seedlings outdoors after all frost danger has passed and soil has warmed. Space plants 24 inches apart in both directions to allow the bushy habit to develop fully without crowding.
Direct sow seeds outdoors after the last frost date once soil has warmed. Press seeds lightly into the soil surface without burying them, as light aids germination.
Pinching back young plants when they're 6 inches tall encourages branching and creates the full, rounded bushy habit these cosmos are prized for. Deadheading spent flowers extends blooming throughout the season.
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