Cosmos bloom in late summer and grow from three to six feet tall. The plants are easy to grow but tend to sprawl so need support or lots of room. Provide a good garden soil, a sunny exposure, and shelter from the wind.
Cosmos are at their best in autumn.
Space plants 10 to 12 inches apart. Over fertilization produces lots of foliage but few blooms. Some shelter from the wind is suggested. The flowers are good for cutting. Some varieties come true from saved seed.