How to Plant and Maintain Cosmos

Mexican Aster, commonly known as Cosmos, (Cosmos bipinnatus) produce beautiful, bright flowers in reds, pinks, purples, and white! They are easy to grow and make good border or container plants. They make for good decorations in flower arrangements (because of their long, thin stems) and also attract birds, bees, and butterflies to your garden.

Cosmos bloom relatively late in the summer. They grow to be about 1 to 4 feet tall and sprawl outward 2 or 3 feet. This plant will tolerate dry, porous soils and is moderately tolerant of drought-like conditions.


  • Cover the seeds lightly with no more than 1/16 in. of soil about 12 to 18 inches apart. Keep the soil moist while they germinate. They germinate in about a week and bloom in about 2 or 3 months.
  • Cosmos love sunlight, so be sure to place them in an area where they receive full sunshine!
  • Don’t over fertilize the plant, because it will not produce flowers if you do!

If you would like to learn more about Cosmos, you can click on this University of Florida link or on this Missouri Botanical Garden’s link!