Easy to grow and abundant in blooms, cornflowers (Centaurea cyanus) are among the most popular annuals grown in zones 3-10. Also referred to as Bachelor Buttons, they reach a height of two feet or more and make excellent cut or dried flowers. Cornflowers feature compact purplish-blue blossoms, although there are other varieties that produce blooms in maroon, sky blue, or pastels. Initial sowing requires some care, but once established in an ideal location, cornflowers often release enough seeds by the end of each season that annual reseeding is often unnecessary in most climates.
Choose an area with full sun and well-drained soil of average moisture. For a long growing season, seeds can be sown as early as in the spring, one to two weeks before the last frost. In mild climates, they can also be planted in the fall.
Lightly press seeds into the soil, one inch apart and a quarter-inch inch deep. Seeds should be completely covered, and they usually take two weeks to germinate.
Wait until seedlings are one to two inches tall before thinning them to six to eight inches apart.
Deadhead by picking off spent flowers to ensure more blooms. Allow some final blooms to die off naturally so they can drop their seeds for the next season.