Very few flowers in the plant world are true blue, but the balloon flower (Platycodon grandiflorus) is one of those few. On top of its unique color (other bloom colors also available), balloon flowers are an easy-to-grow perennial that require very little maintenance and the unusual name comes from the way the flower bud resembles a blown up balloon just before it bursts open into a blue bloom.
Balloon flower, also called Chinese bellflower, is a late-season bloomer that is admired for its multitude of blooms as well as its unusual blooms shape and blue color. Hardy in zones 3 to 8, balloon flowers will put on a dazzling display in the July and August heat when most other flowers have completed their blooming cycle or have slowed down due to the summer heat.
Small, balloon-shaped buds appear on the plant and begin to enlarge until the reach approximately an inch in diameter, then they will burst open into a bell-shaped flower with five points. Blue is the most popular bloom color, with pink or white bloom colors also available. Balloon flowers make long-lasting cut flowers and can be cut off the plant throughout the growing season. The more you cut, the more blooms the plant will produce.
Balloon flowers enjoy full sun but will grow in partial shade. Sow seeds in spring right after the last frost of the season and thin plants to one to two feet apart. Mature plants will reach 1 to 3 feet tall and 1 to 2 feet wide and bear a continuous supply of mesmerizing balloon flowers all over the plant. Plants are slow to appear in following years and are easily forgotten because of their late arrival, using a marker of some type to mark their location will help prevent you from planting something else on top of them. Remove spent blooms to keep the plant looking neat and encourage more blooms. Water plants once a week during times of little rainfall.
After the seedlings have become established, apply a 2 inch layer of organic mulch to the plants. Don’t fertilize the first growing season, wait until the following spring and apply a balanced 10-10-10 fertilize to the soil.
Because the plants grow so tall (up to 3 feet) and produce an abundance of blooms, they tend to flop over and benefit from a support system. Use a trellis or stake to hold the plants upright.