Carthamus is a hardy annual that flowers in the middle of summer. it can reach a height of about one metre.
Carthamus has tubular flowers that may be yellow or orange in colour.
Carthamus is often used for culinary purposes.
Names of some of the plants in the genus include Safflower (Carthamus tinctorius), False Saffron and Saffron thistle.
Carthamus lanatus by Tony Rodd.
Carthamus tinctorius by Yaisog Bonegnasher.
Common Names: Safflower, Saffron Thistle, False Saffron, Distaff Thistle.
Life Cycle: Hardy annual.
Height: 30 to 36 inches (75 to 92 cm).
Growing Zone: Zones 3 to 9.
Flower Details: Yellow or orange. Tubular.
Foliage: Thistle-like. Prickly.
Sow Outdoors: 1/4 inch (6mm). Early spring before last frost or late autumn. Spacing 6 to 10 inches (15 to 25 cm).
Sow Indoors: Peat pots. Germination time: one to two weeks. Temperature 60 to 70°F (15 to 21°C). Seven or eight weeks before expected last frost. Transplant outdoors following the last frost.
Requirements: Full sunlight. Soil pH 6 to 7. Dry soil. Light soil. Poor soil. Use mesh to protect from rabbits.
Miscellaneous: Many culinary uses, often sold as 'saffron' in markets.
When growing Carthamus from seed outdoors it should be planted at a depth of 6 mm in light soil of pH 6 to 7 in the early spring, before the last frost of the season. When growing Safflower from seeds indoors they should be sown in peat pots about 8 weeks before they are ready to be transplanted in mid-spring. Safflower seedlings should be planted out with a spacing of 15 to 20cm in a sunny part of the garden.
If you are growing Carthamus for culinary purposes then the flower heads should be cut off at the end of summer, and dried. Carthamus makes a good replacement for expensive saffron. In addition to direct use in cooking, safflower oil is often considered a healthier option than using sunflower oil.
Amazon USA PDF - Guide to Annual Plants