Carthamus tinctorius L.

Herbs (20-)50-100(-150) cm tall, annual. Stem erect, apically branched; stem and branches white or whitish, smooth, glabrous. Leaves rigid, leathery, glabrous. Lower and middle stem leaves sessile, lanceolate, ovate-lanceolate, or elliptic, simple, 7-15 × 2.5-6 cm, base attenuate and semiamplexicaul, margin spinosely toothed or entire, apex acute; teeth very rarely pinnatipartite, apically with 1-1.5 mm spinules. Upper stem leaves lanceolate, decreasing in size upward, margin spinosely toothed; teeth apically with a ca. 3 mm spine. Capitula few to many, in a corymbose synflorescence, rarely 1. Involucre ovoid, ca. 2.5 cm in diam. Phyllaries in ca. 5 rows; outer phyllaries leaflike, ovate-lanceolate, 2-4 × ca. 1 cm, spiny; middle phyllaries 6-20 × 4-7 mm, constricted between pale parallel-veined basal part and leaflike apical part with green reticulate veins; inner phyllaries oblanceolate-elliptic to oblanceolate, ca. 22 × 5 mm, rigidly scarious, apex attenuate. Corolla red to orange, ca. 2.8 cm. Achene ovoid to ellipsoid, ca. 5.5 mm, 4-angled. Pappus absent. Fl. and fr. May-Aug. 2n = 24*.

It grows in both tropical and temperate zones. It does better in drier regions. It cannot tolerate waterlogging. It does not suit the low wet tropics. It needs a good dry season for drying. It is resistant to drought. It can stand some wind and salinity. High temperatures can result in poor seed set. It does best where temperatures are 17-20°C on average. At the equator it can grow at 1600-2000 m altitude but most commonly in other regions it grows below 900 m altitude. It grows to 3,000 m altitude in Ethiopia. A pH of 5-8 is suitable. It can grow in arid places. It can grow in salty and alkaline soils. It suits hardiness zones 4-10. Tasmania Herbarium.

The young shoots and leaves are eaten cooked or raw. They can be seasoned with soy sauce. The seeds are hulled and roasted. They are eaten as snacks. They are also used in chutneys. The seed oil is used in cooking and as a salad oil. (This can be done by boiling the seeds and floating off the oil.) The dried edible petals are used to colour foods. They can give red or yellow dyes. The slightly bitter petals can be cooked with rice.

Plants are grown from seed. A fine seed bed is required and seed are broadcast or drilled. It is best sown about 2-3 cm. Seeds germinate in 4-7 days and are best at 15°C. Plants should be topped as soon as the first buds appear to increase the number of flower heads. A spacing of 15-30 cm between plants is suitable. Wider spacing gives more heads per plant and closer spacing gives higher yields per area. A seeding rate of 20-30 kg per hectare is required. Crops respond to fertiliser if there is sufficient moisture. In very dry weather, harvesting in the more moist morning or evening avoids seed shattering. Plants are uprooted and heaped for a few days before threshing.