Callistephus

Callistephus is a genus of flowering plants in the family Asteraceae, native to East Asia. The best-known species is Callistephus chinensis, commonly known as the China aster. Plants are annuals or short-lived perennials in cultivation, producing upright stems and showy flower heads.

Description: The inflorescences are heads 4–8 cm across, with a central cluster of disc florets surrounded by ray florets that can be single or doubled. Colors range from white, pink, purple, red to blue; flower forms include single, semi-double, and double types.

Taxonomy and distribution: Callistephus is often treated as a distinct genus in the Asteraceae. The species is native to China and surrounding regions, and has been widely cultivated and naturalized in temperate regions worldwide.

Cultivation: In gardens, China asters are grown as annuals for borders and as cut flowers. They are usually sown indoors in early spring or sown directly after frost. They prefer full sun and fertile, well-drained soil. Most varieties reach 60–120 cm in height. Regular deadheading promotes longer bloom.

Horticultural significance and varieties: Since the 18th century, numerous cultivars and hybrids have been developed. They are valued for late-summer to autumn displays and for use in bouquets.

Pests and diseases: Powdery mildew, leaf spots, botrytis, aphids, and thrips can affect plants; good air circulation and hygiene reduce issues.