Cosmos 'Sea Shells' has interesting fluted petals, each rolled round a tube, like a sea shell. It makes a great planting partner for dark-flowered dahlias and chrysanthemums, and both its flowers and foliage work well in cut flower arrangements.
Cosmos flowers are best established in masses, in open fields, borders and flower beds and in random areas that need a splash of color. Most Cosmos flowers grow to a height of at least 30 inches or taller, so you may consider using them as a background / backdrop plant.