Slow to emerge their new growth in spring, Chinese bell flower plants (Platycodon grandiflorus) are worth the wait as their airy flower stems lend beauty to the cottage garden or rockery. Cut the stems and use in a vase bouquet, too, to add blue and purple tones to a floral arrangement. This herbaceous perennial is best grown in U.S. Department of Agriculture winter hardiness zones 3 through 8.
Although called Chinese bell flower, this herbaceous perennial is native to a wide region from eastern Siberia into northern China, including Manchuria, and eastward into Korea and Japan. It grows on mountain slopes and highland meadows.
Chinese bell flower typically grows 24 inches tall, with a compact clump of foliage only 12-inches wide at most. The leaves are lance- to oval-shaped and bluish-green in color. In midsummer, tall stems bear flower buds that look like 19th century hot air balloons, the reason why this plant is also called "balloon flower." The buds open to a five-petaled, bell-shaped blossom with pointed tips. Flowers range in color from purple-blue to mauve, pink or white. Plants that grow from seed and sometimes develop with pink and white variegated flowers even though the parent plants where blue-flowering according to the "A-Z Encyclopedia of Garden Plants" from the American Horticultural Society.
Plant Chinese bell flowers in a deep, crumbly loam that is both fertile and moist but well-draining. They grow in full sun exposures as well as in partial shade, where dappled sunlight occurs or plants receive between three and six hours or sunshine daily. Tall-stemmed plants may need staking to prevent flower stems from flopping over in breezes or in heavy rain downpours.
These perennials resent root disturbance, so as a general rule, they are best sown from seed in the exact spot where you wish them to grow. If you transplant from nursery-grown containers, take care when planting so you do not destroy the integrity of the root ball. To propagate Chinese bell flowers, divide plants or detach the basal shoots in early summer. Slugs and snails tend to relish eating young plants.
There are different natural forms of Chinese bell flower plants that can be grown to take advantage of their varied mature sizes or flower characteristics. Albus produces white flowers with blue veins while apoyama grows only 8 inches tall, with deep-violet blooms. Another dwarf type is the subspecies mariesii. Horticulturists have developed cultivars, such as those in the Balloon Series. Names of cultivars includes "Komanchi," "Mother of Pearl," "Shell Pink," "Plenum," "Baby Blue" and "Park's Double Blue" just to name a few on the market.