Plants from the genus Callistephus are half or full hardy annuals.
They are bushy in nature, and range in height from 20 to 80 cm (8 to 32 inches).
The blooms of Callistephus are similar to those of Chrysanthemums.
They flower in the summer in almost all colours, these often have a yellow centre.
The common name for this garden plant is the China Aster.
Both Photographs of China Aster (Callistephus chinensis) by Carl E Lewis
In the garden these plants look great as part of a border. They are also used often as a cut flower in floral arrangements.
Unfortunately, these are not the easiest of plants to care for.
There is only one member of the Callistephus genus, the China Aster (Callistephus chinensis). As the name suggests the plant is a native of China.
Plants carry long, toothed ovate leaves of about two to three inches in length (5 to 8 cm). They usually have Chrysanthemum like flowers, though some varieties may have only simple ray florets.
In many cases, the central disc florets are yellow in colour. Outer petals are of many colours; purple, red and pink are very common.
The original native species carries single white flowers.
As it is a popular garden plant, there are many different varieties available, meaning that the species is available with many different petal colours and sizes; dwarf varieties may be as little as eight inches (20 cm); taller varieties may reach 32 inches (80 cm).
Some of the commonly grown varieties of Callistephus chinensis include Lilliput blue moon, Pink tower, Ostrich plume, Blue ribbon, Hulk, Red ribbon, and Seastar.
As a member of Asteraceae (Compositae) (the Daisy family), Callistephus is closely related to species such as Chrysanthemum, Calendula, Tagetes, and Dahlia.
Callistephus chinensis is the only species in this genus.
Callistephus chinensis (China Aster / Annual aster), photograph by Josep Maria Viñolas Esteva; CC.
Callistephus chinensis single (Single China Aster), picture by Maja Dumat; CC.
Callistephus chinensis red (Red China Aster), picture by Tim Green; CC.
Callistephus chinensis Purple (Purple China Aster), picture by 阿橋 HQ; CC.
Callistephus chinensis Pink and Yellow (Pink and Yellow China Aster), picture by Ott Rebane; CC.
If you are planning to grow Callistephus, then the seeds should be lightly covered once sown. Sow in the spring, following the last frost.
If you initially plan to grow China Aster as seedlings indoors, for later transplanting, then they should be germinated at a temperature of 18 to 21°C (64 to 70°F) for two weeks.
Seeds should be sown in peat pots. Use aa vermiculite mix and provide water supplied from below.
After about seven or eight weeks, the seedlings can be planted in the garden in an area of partial shade or full sun. Use a spacing of 20 cm (8 inches, dwarf) 40 cm (16 inches, medium) or 60 cm (24 inches) for larger species.
They prefer to grow in a rich soil that has good drainage, and a pH of 6 to 7.
Callistephus chinensis are not the easiest plants to look after, they should be carefully watered when it is dry. Plants require a couple of feeds when growing.
Additionally, they should be staked, dead headed, and require careful weeding of plants in the area. It is good to rotate Callistephus's location every year.
Further information on caring for Callistephus is given in the 'requirements; section of the quick growing guide above.