What is Centaurium?

Centaurium is a genus of 30 flowering annuals, biennials, and short-lived perennials in the Gentian family of plants found mainly in tropical, subtropical, and temperate climates of North America, Europe, and Asia. Two species are in danger global extinction. Plants in this species are often used in rock gardens or in flower beds. In traditional medicine,Centaurium has been used for hundreds of years as a remedy for gastric and skin conditions.

Centaurium erythraea, Centaurium minus, and Centaurium umbellatum are known as common centaury or European centaury. These species are native to Europe, north Africa, and western Asia, and have been naturalized in North America and parts of eastern Australia. They can be found growing in deserts, mountains, grasslands, along the coast, or by the side of the road.

Centaurium namophilum, or spring-loving centaury, grows in California and Nevada in the U.S. It is imperiled globally, which means that the species is vulnerable to extinction with only 1,000-3,000 individual plants left in the wild. Centaurium sebaeoides, known as awiwi, grows in Hawaii. This species has been red-listed as critically endangered by the International Union for the Conservation of Nature. This means that fewer than 1,000 individual plants are left in the wild.

These plants typically grow from 6 to 18 inches (15.24-45 cm) tall. From June to September, they produce clusters of five-petaled blooms in pale pink to reddish purple. Flowers are approximately 0.5 inches (13 mm) wide, and the dark green leaves are oblong with pointed tips. Centaurium species are often used in rock gardens and as borders in garden beds. In cold climates, seeds can be sown in early spring; in more moderate climates, seeds can be sown in the late summer or early fall.

Species in this genus grow well in U.S. Department of Agriculture Hardiness Zones four through nine and can tolerate temperatures as low as -30° Fahrenheit (-3.8° Celsius). They thrive in full sun or partial shade and prefer soil with a mildly acidic to mildly alkaline pH level. Plants require regular watering, but should not be overwatered.

Traditionally, European centaury has been used to treat digestive or skin complaints. When taken as a tea, it stimulates the salivary glands and promotes digestion. People often drink the tea to calm heartburn or colic, although strong tea can induce vomiting. This species of Centaurium is also made into a lotion that, if used regularly, is said to fade freckles and age spots on the skin.