Family: Asteraceae
Common Name: Tickseed

These hardy annuals and perennials are grown for their showy, daisy-like flowers. They do well in hot, dry spots in the garden and make excellent border plants, often growing under conditions other annuals and perennials find intolerable.

Species

C. gisantea, zone 8, is the only succulent species. It has a tall, thick, fleshy stem to 2 m (6 ftl high, fern-like leaves, crowded at the apex, and flat-topped clusters of bright yellow flowers in summer.

C. grandiflora, zone 7, is a clump-forming perennial which grows 50-90 cm (20-36 in) high. It flowers from spring to late summer with disc florets much darker than the surrounding rays, or petals, especially in cultivars like 'Early Sunrise'.

C. lanceolata, zone 3, is a perennial, to around 50 cm (20 in), with bright yellow flowers in summer and autumn. This species has become naturalized in many parts of the world and is often seen on roadsides and along railway lines.

C. tinctoria, zone 3, has also become naturalized in some places. This annual produces yellow or crimson flowers, and a number of cultivars offer a range of colours from yellow and bronze through to crimson and maroon.

C. verticillata, zone 6, has fine, feathery foliage and early summer flowers. It grows 50-80 cm (20-32 in) high.

Cultivation

These plants like full sun, but must be watered only periodically. Propagate annuals from seed sown in spring and early summer and the perennials from seed sown in spring outdoors, or in late winter under glass. Simply scatter the seed into spare corners of the garden after the soil has been dug over. If kept moist, the seed will germinate freely. Thin at seedling stage to about 20 cm (8 in) apart. The perennials can also be propagated by stem cuttings in spring or early summer, or by division of the clumps in autumn.

Climate

There are species suited to various climatic zones.