Safflower: growing, care & benefits

With its vibrant petals, safflower is not only an eye-catching feature in the garden but also has a wide range of different uses – from dyeing to medicine and oils for cooking.

The safflower plant (Carthamus tinctorius), sometimes called saffron thistle, forms a beautiful thistle-like shape. Its unique ornamental value and low-maintenance nature make the safflower an intriguing plant to consider growing in your garden. Discover more about the characteristics, sowing and use of safflowers here.

Safflower: origin and characteristics

Safflower is also known by other names such as American saffron, oil thistle, false saffron, dyer’s saffron, majestic orange, zaffer and Mexican saffron. It is hard to pinpoint the exact origin of the safflower as it is widespread throughout the world, but it is widely assumed that it originated in Anatolia. The plant in its current form, Carthamus tinctorius, is probably a hybrid cultivated from the cross-breeding of the species Carthamus persicus and Carthamus palaestinus at some point in the distant past. We know that the plant was used for dyeing textiles in Egypt as early as 3500 BC.

Although safflower is an annual plant, in the tropics and subtropics it has been known to overwinter. In Central Europe, however, the specimens that germinate in autumn usually do not make it through the winter. Only spring seedlings will flower in the same year. The herbaceous plant belongs to the daisy family (Asteraceae) and forms a large, deep taproot. Its slightly branched main stems reach 60 to 130 cm in height and form a rosette of leaves. The elongated safflower leaves are vibrant green in colour and have spiked edges. Depending on the species and variety, the spiny tips are more pronounced or less. At the end of each shoot is a thistle-like flowerhead made up of 20 to 150 yellow-orange tubular florets. The distinctive bulb-shaped flowers bloom from June to August, offering bees, bumblebees and other insects a rich supply of nutritious nectar and pollen.

How to grow safflower

Safflower seeds for planting can be purchased from seed suppliers online or from specialist garden centres. After successfully growing safflower from seed for the first time, you can harvest the seeds and use them to propagate more flowers the following season. Collect the seeds from the flower heads in September and October.

As a fast-growing summer flower, safflower can be sown directly outdoors from mid-April to early June – there is no need to start the seeds on a windowsill or under protection. You can even sow safflower seeds in autumn. Carthamus tinctorius seeds can survive the winter, withstanding temperatures right down to -10 °C, and then simply germinate the following year. As the plant forms a taproot, it is less suitable for growing in pots. If you decide to do so anyway, use a deep container filled with a mixture of potting soil and 30 to 40% drainage material.

When deciding where to sow safflower seeds outdoors, the best choice is a warm and sunny location with loose soil. This supports the germination process and healthy development of the plants. Sow the safflower seeds at a distance of 20 to 30 cm, about 2 to 3 cm deep in the soil. Ideally the soil should be well-drained sandy clay loam. If it is too clay-rich, improve the soil with plenty of sand. While the plants are still young, make sure they have a regular supply of water. After a germination period of about two to three weeks, the first little seedlings will appear.

Good companion plants: the safflower fits wonderfully in any rustic cottage garden, as a centrepiece in mixed borders or as a temporary guest in perennial borders. When choosing suitable companion plants, musk thistle (Carduuns nutans), chicory (Cichorium intybus), Scotch thistle (Onopordum acanthium) and viper’s tongue (Echium vulgare) are all worth considering.

Safflower care

If your safflowers get a good start to life, hardly any further care is necessary. Thanks to its deep taproot, it can usually supply itself with enough water and nutrients. A constant supply of fresh water is helpful in spring, but the plants do not mind dryness in summer.
To support the growing plants with all the essential nutrients, mix a slow-release fertiliser into the soil before sowing. Our Plantura All Purpose Plant Food, for example, is well suited to this – its balanced nutrient composition ensures lush green foliage, healthy plant growth and abundant flowering. What’s more, it is made using 100% plant-based materials and valuable minerals, with no animal waste products.

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Is the safflower winter hardy? Safflowers can withstand temperatures all the way down to about -7 °C. However, as an annual plant, it dies off at the end of winter and has to be resown the following year. So its capacity to survive the winter does not make much difference.

How to use Carthamus tinctorius

Carthamus tinctorius is cultivated agriculturally to produce safflower oil from the seeds. The oil is packed with unsaturated linoleic acid and vitamin E, and can be used in cooking as well as for the production of paints and varnishes. Safflower is also used to dye textiles. To do this, the intensely coloured petals are first washed and then dried. Finally the typical safflower red is obtained using an alkaline solution.

Safflowers have various medicinal and healing benefits too. For example, the dried petals can be used to make safflower tea infusions. This is said to reduce fever and relieve pain.

There is also a reason the plant is often called false saffron – its petals can be used as a substitute for the costly saffron. However, when comparing the two, the similarity ends with their colour – safflower tastes much milder than the real saffron.

Finally, safflower is often used in floristry as a dried or cut flower. The thornless varieties are particularly popular for this.

Safflower benefits

Safflower oil is said to be extremely beneficial for health due to its high content of unsaturated fatty acids. Not much research into safflower oil benefits has been completed. According to some studies, however, safflower oil can lower high cholesterol levels and even have a positive impact on diabetes. 

Another plant with thistle-like flowers and great ornamental value is the globe thistle. When in bloom, it is also a magnet for attracting bees and bumblebees to the garden. To discover more about this flower and how to care for it, read our article on the globe thistle.