Carthamus is a genus of flowering plants containing a small number of species native to the Mediterranean region. The most famous representative of this genus is C. tinctorius, the safflower, a plant that has been cultivated for thousands of years, according to evidence from Ancient Egypt, Greece, China, and India. Today, this plant is used primarily as a source of oil, with safflower oil being a popular cooking product in many regions of the world.
These members of the daisy family are typically annuals, with many growing over the winter months. They produce green, spiky foliage and bright yellow, thistle-like flowers. They are sometimes known as distaff thistles. In many regions, they are treated as a noxious weed, and they can become a particular problem in pastures, where livestock may eat them and become ill.
In the case of the safflower, the plant has a number of uses. This particular Carthamus species was used historically as a source of yellow dye and is sometimes known as dyer's safflower. The distinctive yellow color also allowed people to use the dried flowers as a substitute for saffron, a very expensive spice, in recipes. This plant is sometimes known as false saffron for this reason.
Medicinally, preparations made from Carthamus plants were used historically to treat joint pain, skin sores, and dysmenorrhea, among other medical conditions. The oil was also historically valuable for cooking, as well as fuel for lamps. Today, safflowers are widely grown in temperate climates so their seeds can be collected and used to make oil, with cold pressed safflower oil being available in many grocery and health food stores. The smoke point of this oil is moderate and it is advisable to avoid it in baking, except for very low temperature recipes.
In areas where Carthamus weeds are a problem, there are a number of control options. Eradication by digging plants up and burning them can work, especially if a weed barrier is applied to prevent the plants from returning. The ground can also be sown with fast-growing, competing plants after the weeds are removed, a consideration in pastures where people may want to allow animals back to graze. Removing plants as soon as they start appearing is advised, before they have a chance to go to seed and spread themselves. Making gardeners aware of the Carthamus problem can be helpful, as they will know to uproot weeds before their seeds have a chance to invade neighboring gardens and pastures.