True blue flowers are hard to come by. There are plenty of purple-blue choices to pick from, but when it comes to finding flowers of a genuine blue hue, the choices are limited. Still, there are a few blue flowers that do perform well; as an added bonus, several varieties come back every year.
The botanical name for the morning glory is Ipomoea tricolor. It is an annual that climbs 10 to 15 feet along a fence or up a trellis. Blue morning glories have large blossoms, and the vine's leaves are heart-shaped. There is also a smaller variety, Convolvulus tricolor, which grows 12 to 18 inches tall and comes in light blue, as well as pink or white. Morning glories bloom from mid-summer until frost. They require little upkeep and can thrive in poor soil. They do need to be watered regularly.
Siberian squill, also known as scilla, has bright blue flowers that grow on 6-inch stems with dark green leaves. The flower stalks emerge from the foliage and produce one or more flowers, each up to an inch wide. Scilla grow in partially shady areas and bloom for about two weeks early in the spring. Scilla is a perennial that is grown from a bulb and has the tendency to spread.
Blue Fringe Daisies
Daisies are a versatile flower that grows well and requires little upkeep, and the blue fringe daisy is no exception. The sky-blue, fringey petals surround a yellow-green center and bloom in midsummer. A perennial, the blue fringe daisy grows to be 18-24 inches tall and does require a sunny spot.
Virginia bluebells, or Mertensia virginica, are a wildflower native to woodlands, but they also do well in shady areas of the garden. They have trumpet-shaped flowers growing from a coiled stalk; they grow to be 1 to 2 feet tall. Virginia bluebells bloom in early to mid-spring. They require a good amount of water.
Lobelia, or Lobelia erinus, produce bright blue flowers from early summer until frost hits. They are annuals and grow 3 to 10 inches tall. Lobelia does not like extreme heat; the flowers will die back during the hottest part of summer but revive as soon as the temperatures drop. They need a good amount of water and fertilizer, and do well in hanging baskets or along the edge of the garden.