April showers bring May flowers, but the month of April is full of bursting blooms, flowering trees and blossoming bulbs as well. Depending on the hardiness zone of the location, April is usually the first spring month when the temperatures warm up on a reliable basis. Flowers that tolerate light frosts are now ready to put on their spring show.
Frost-tolerant annuals started indoors under grow lights, or a sunny window sill, and set out in late March will start to bloom in April. Cool season flowers prefer lower temperatures rather than summer heat. Pansies and violas are two that bloom profusely. Violas are similar to pansies without the "cat face." Johnny jump ups are pansies in miniature. While the plants grow to the same size as pansies, Johnny jump up flowers are the size of a quarter compared to the size of pansies which are 1 1/2 to 2 inches across.
Snapdragons are another cool-season flower. The size of the flowers are relatively small, perhaps an inch long, but come packed on stems from 6 inches to 36 inches tall, depending on the snapdragon variety. Snapdragons don't come in blue.
Larkspur starts blooming in warmer areas of the U.S. in April. The bushes are from 3 to 4 feet tall with feathery leaves. Colors include blue, purple, light pink, bright pink and white. Sometimes the flowers are edged with a contrasting color.
Spring bulbs achieve their glory in April, starting with daffodils and ending with late-blooming tulips. Grape hyacinths, ranunculus and freesia are other bulbs blooming at this time. In southern areas of the U.S. Iris, bearded Iris and amaryllis start to bloom in late April. Amaryllis is better known as a bulb grown indoors during the holiday season. The flowers grow three to five blooms on a stem 2- to 3-feet-tall hollow stem. The blossoms are up to 6 inches across; colors include red, pink and white. After several seasons the bulbs will start producing baby bulbs which can be separated and replanted.
Columbine floats blossoms above its leaves; the flowers are trumpet shaped with a frill around the back end of the trumpet. They do well in shade and tolerate damp soil. Cornflowers are the perennial version of bachelor buttons and bloom in bright blue, pink and more rarely white. The flowers are little puffs of petals about half the size of a golf ball. Another striking blue flower is delphinium which can grow up to 8 feet tall. Delphiniums require staking or they will flop over during spring rain. Digitalis or foxglove starts to bloom at the end of April. The flower is poisonous, as well as the leaves and stems, so keep away from children and pets.