Cosmos

Colorful Combinations

Depending on the variety, cosmos features single saucer-shape flowers with yellow centers and white, pink, or red rays. This annual’s green leaves are deeply cut into feathery threadlike segments. Cosmos cultivars sport a larger number of colors than regular cosmos, including bicolor, expressed in single, semi-double, or double flowers. Look for sizes ranging from dwarf to tall.

Cutting Garden Essential

Pair cosmos with three or four other easy-to-grow annuals and enjoy weeks of freshly cut flowers right from your own garden. Anchor the cutting garden with multiple varieties of cosmos. Try ‘Cupcake White’ or ‘Psyche White’ along with the ‘Sonata’ mix in white, pink, rose, and cherry. You may also want to include other annuals like zinnias, sunflowers, larkspur, bells of Ireland, and bachelor’s buttons.

For a low-maintenance cutting garden that is low-cost, too, grow cutting flowers from seeds planted in rows. The row-style planting makes it easy to manage weeds. A $15 investment in seeds will yield armloads of flowers in multiple varieties.

Cosmos Care Must-Knows

This tough warm-weather annual does best in well-drained soil in full sun. Directly sow cosmos seeds in the garden just before the last frost date in spring. Sow seeds 2-3 inches apart and ¼-inch deep, then lightly cover with fine soil and water well. Seedlings will emerge in 5-10 days. Keep the seed bed well weeded and watered. Cosmos will begin blooming about two months after planting. If you prefer to start seeds indoors, do so 6-8 weeks before your last frost date in spring.

Plants that come from tall cosmos varieties should be spaced close to each other for support. They still may need staking. Use tall bamboo stakes and garden twine to support plants quickly and easily. Deadhead spent flowers to encourage plants to unfurl new flowers. Leave some flowerheads for self-seeding, if desired. When planted in the garden, cosmos does not need fertilizer. Plants growing in containers flower best when fertilized every two weeks or so with an all-purpose garden fertilizer.

More Varieties of Cosmos

‘Sonata White’ cosmos

Cosmos ‘Sonata White’ bears pure-white flowers on sturdy, 18-inch-tall plants.

‘Cosmic Yellow’ cosmos

Cosmos sulphureus ‘Cosmic Yellow’ is a compact selection with double yellow flowers over dark green foliage. It grows 12 inches tall.

‘Cosmic Orange’ cosmos

This cultivar of Cosmos sulphureus bears many double orange flowers that are great for cutting. It grows 12 inches tall.

‘Sensation’ cosmos

This Cosmos mix bears large, 4-inch-wide flowers in a mix of lavender, pink, red, and white on plants that can reach 5 feet tall.

‘Versailles’ cosmos

This Cosmos variety is especially good for cutting because of its strong stems and large flowers in shades of pink, white, and red.

Yellow cosmos

Cosmos sulphureus bears orange, yellow, or red flowers and finely divided foliage.

‘Candystripe’ cosmos

Cosmos bipinnatus ‘Candystripe’ has pure white petals edged in deep pink. It reaches 3 to 5 feet tall. Zones 2-11

Cosmos Companion Plants

Celosia

There are few flowers as showy as celosia. Whether you plant the plumed type, which produces striking upright spires, or the crested type, which has a fascinating twisted form, you’ll love using celosia in bouquets. The flowers are beautiful fresh, but you can also dry them easily. And they bloom in all the colors of a glowing sunset. Plant established seedlings in spring after all danger of frost has passed. Celosia likes rich, well-drained soil with moderate water. Spider mites can sometimes be a problem in hot, dry weather.

Dusty Miller

Dusty miller is a favorite because it looks good with everything. The silvery-white color is a great foil for any type of garden blossom and the fine-textured foliage creates a beautiful contrast against other plants’ green foliage. Dusty miller has also earned its place in the garden because it’s delightfully easy to grow, withstanding heat and drought like a champion.

Salvia, Sage

There are few gardens that don’t have at least one salvia growing in them. Whether you have sun or shade, a dry garden or lots of rainfall, there’s an annual salvia that you’ll find indispensable. All attract hummingbirds, especially the red ones, and are great picks for hot, dry sites where you want tons of color all season. Most salvias don’t like cool weather, so plant them outdoors after all danger of frost has passed.