Popular blue annual flowers include the baby blue eyes flower, which is a spreading shrub-like wildflower, and the winter-blooming blue larkspur flower. Another blue annual flower is the bachelor's button flower, also known as the cornflower or bluebottle flower.
The baby blue eyes flower, also called the California blue bells flower, has six curved blue petals. The plant ranges from 6 to 12 inches tall and blooms from late winter to late spring. It has a spread of 12 inches and does well in partial shade conditions. Baby blue eyes plants are easy-growing and flower best in sandy soil.
The blue larkspur flower is similar to the well-known perennial flower delphinium. Blue larkspur flowers range in height from 1 to 8 feet and are 6 to 12 inches wide. They are low-maintenance plants, but the seeds do require a cold period to germinate. Larkspurs are tall plants, so they are planted with stakes that can accommodate 8 feet.
The bachelor's button flower has many nicknames, including hurtsickle, cyani flower and boutonniere flower. It grows from 16 to 35 inches tall and produces blue flowers in flowerheads. The bachelor's button flower's natural habitats include cornfields and prairies, but over time the plant became endangered in these areas due to overuse of herbicides.