Cosmos bipinnatus 'Sea Shells' – Quilled Tube-Petaled Annual Cosmos

Cosmos bipinnatus 'Sea Shells'

Cosmos bipinnatus 'Sea Shells' (KOZ-mose by-pin-AY-tus) is a unique annual producing quilled blossoms of hollow, tube-shaped petals radiating from the center in shades of white, pink, or carmine red. Flowers bloom all summer long, sometimes with bicolored interior and exterior tubes.

Noteworthy Characteristics

• Mexican native loved by butterflies
• Excellent cut flowers
• Ideal for cutting garden, mixed border, or annual border

Growing Conditions & Care

Deadhead to prolong flowering, and leave some seeds to self-sow. Plants are moderately drought and heat tolerant.

Propagation

Sow seed in situ in late spring or at 61°F in mid-spring.

Potential Problems

Stem canker, powdery mildew, Rhizoctonia stem rot, gray mold, aphids.

Quick Reference

• Height: 3–6 ft.
• Spread: 6–12 in.
• Light: Full sun only
• Moisture: Dry to medium
• Maintenance: Moderate
• Bloom Time: Early fall to summer
• Flower Color: Pink, Red, White
• Uses: Beds, borders, cut flowers, cottage gardens
• Type: Annual
• Special: Drought tolerant