Cosmos is a Hardy Plant with Showy Flowers

Featured Photo Credit: K.M. Ferdous Hasan Foysal via

plants are highly resilient, blooming lavishly from early or midsummer to fall, depending on variety, and have beautiful cut leaves, spectacular blooms, and a lengthy blooming season. They are often used in pollinator gardens to attract birds, bees, and butterflies.

Quick Growing Guide

Botanical Name: Cosmos bipinnatus

Botanical Family: Asteraceae

Also Called: Garden cosmos, Mexican Aster

En français: Cosmos bipinnatus



Sun / Shade:

Water: Tolerates drought, don’t over water.


Hardiness Zones:

Cosmos are freely flowering annual plants in the asteraceae or sunflower family. They are super easy to grow. If you’re looking for a flower that will stay in bloom for months and can be grown easily by scattering seeds, cosmos are a great choice.

Cut flowers last more than a week in fresh bouquets. Saucer-like blooms stand out against a backdrop of fine, airy foliage.

Ideal choice for beds, borders, and cutting gardens. Excellent backing plant for mixed borders.

They are very popular plants that often symbolize order and harmony. The word “Cosmos” comes from the Greek word meaning “harmony and ordered universe.”

Propagating Cosmos bipinnatus

Sow seeds directly in soil after the threat of frost has ended. From seed, first flowers appear in about 7 weeks, after which you can expect them to flower continually until the first frost. Young plants may be transplanted from pots at this time. Rich soil will encourage foliage rather than blooms, so it is not necessary to make any special soil preparations.

Caring for Cosmos

Cosmos grow easily in beds, and they make great cut flowers. When established, the plants can handle drought, poor soil conditions, and general neglect. They even self-sow. May reseed, for a surprise return next season, if dried flower heads are left intact.

Companion Plants

Cosmos is a Mexican native that grows as a perennial in zones 9 and 10. It’s a popular annual in other parts of North America. It looks great when planted in masses or as a filler in mixed settings. Baby’s Breath, Coreopsis, Russian Sage, Daisies, Asters, Black-eyed Susans, and many more are good companion plants for cosmos.

Pruning Cosmos bipinnatus

Pinch to create more flowers. Some varieties re-bloom in about a month.


Susceptible to stem canker, powdery mildew, aphids, flea beetles or gray mould. These are easy to control with insecticidal soap, or by spacing plants accordingly to ensure quality air flow.

Cosmos plants were brought back to Madrid in the 16th century by Spanish explorers. Seeds were brought to England in the late 1700’s and made their way to the United States around 50 years later.

Sources and References

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