Alphabetical Plant Listing

Cosmos Flowers

Mexican Aster, Orange Cosmos, Yellow Cosmos, Cosmos bipinnatus, Cosmos sulphureus, Sulphur Cosmos, Cosmos atrosanguineus, Chocolate Cosmos (Cosmos)


With finely cut leaves, showy flowers and a long blooming season, Cosmos are half-hardy annuals or perennials blooming profusely from early or midsummer until fall, depending on varieties. Ridiculously easy to grow, fairly pest-free and low maintenance, they attract birds, bees, and butterflies to your garden. They are grown in borders, in containers and for cutting. They make excellent cut flowers thanks to their long vase life and richly colored petals which compliment any bouquet.

Native to Mexico, most of the cosmos we grow derive from three species:

Cosmos atrosanguineus (Chocolate Cosmos)

Highly sought after, Cosmos atrosanguineus are half-hardy, tuberous perennials boasting chocolate-scented, velvety deep crimson flowers, up to 2 in. across (5 cm), from midsummer to fall. Their pinnately divided leaves are often lobed at the base and are attached to the stems by winged petioles. These profuse bloomers create a striking visual impact in the garden and look particularly outstanding when combined with ornamental grasses. They are also ideal in containers where their fragrance can be enjoyed.

Cosmos atrosanguineus

Cosmos atrosanguineus Chocamoca

Cosmos bipinnatus (Mexican Aster)

True eye-catchers, Cosmos bipinnatus are bushy, half-hardy annuals boasting single, semi-double or double daisy-like flowers, as large as 5 in. across (12 cm), in a wide array of colors including pink, white, red and bicolor varieties. Blooming for months from early summer to fall, the ravishing blossoms are borne atop branching stems and float above the fine, feathery foliage. Ranging from 2-5 ft (60-150 cm), tall varieties are ideal towards the back of mixed borders or in a row for cutting, while smaller cosmos varieties are perfect for the patio and terrace or at the front of borders.

'Sensation Picotee'

'Xanthos'

'Double Click Rose Bonbon'

Click here to see all Cosmos varieties

Cosmos sulphureus (Sulphur Cosmos)

Also called Orange Cosmos or Yellow Cosmos, Cosmos sulphureus are half-hardy annuals boasting vibrant, semi-double or double flowers, up to 2 in. across (5 cm), in shades of yellow, orange or scarlet. Neat and tidy, with profuse blossoms and slightly broader, darker leaves, these cosmos generally grow up to 1-3 ft tall (30-90 cm) and perform very well in hot climates. Bringing showers of sparks in the landscape or containers, they can also be cut.

'Cosmic Yellow'

'Bright Lights'

'Cosmic Red'

Click here to compare all Cosmos varieties

Growing Cosmos Flowers

  • Cosmos perform best in full sun, in average, moist, well-drained soils. They like soil that is not too rich, as rich soil will encourage foliage at the expense of bloom.
  • They are ideal additions to beds and borders, containers, cottage gardens, prairies and meadows and cutting gardens.
  • Cosmos are perfect for mixing with roses (such as summer-long hybrid musks, English roses), or with buddlejas, border phlox, penstemon, monardas, campanulas or veronicas.
  • Propagate by seeds. Seed can be sown outside after the danger of frost has passed. It takes about 7 weeks to first bloom. If you want a head start, you can plant cosmos indoors 4-6 weeks before the last spring frost.
  • Pinching off dead blossoms will promote continuous blooming. If the flower heads remain, the cosmos will self-seed, but will not become a nuisance.
  • Keep an eye out for aphids, slugs, gray moulds.

'Double Click Cranberries'

'Sonata White'

'Xsenia'

Click here to find Pretty Garden Ideas with Cosmos

Guide Information

Hardiness 2 - 11
Heat Zones 1 - 12
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 1A, 1B, 2A, 2B, 3A, 3B
Plant Type Annuals
Plant Family Cosmos
Exposure Full Sun
Season of Interest Summer
Fall
Water Needs Average
Maintenance Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Cut Flowers, Showy
Attracts Butterflies, Hummingbirds
Landscaping Ideas Beds and Borders, Patio and Containers
Garden Styles City and Courtyard, Cutting Garden, Traditional Garden

Pictures are courtesy of National Garden Bureau, Benary, Botanik Foto, sakurai_dayo

While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.

Guide Information

Hardiness 2 - 11
Heat Zones 1 - 12
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 1A, 1B, 2A, 2B, 3A, 3B
Plant Type Annuals
Plant Family Cosmos
Exposure Full Sun
Season of Interest Summer
Fall
Water Needs Average
Maintenance Low
Soil Type Chalk, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Cut Flowers, Showy
Attracts Butterflies, Hummingbirds
Landscaping Ideas Beds and Borders, Patio and Containers
Garden Styles City and Courtyard, Cutting Garden, Traditional Garden
Not sure which Cosmos to pick?
Compare All Cosmos
Great Plant Combination
Ideas with Cosmos
Guides with Cosmos

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