It is a herbaceous perennial plant growing to 80 cm tall. The leaves are glaucous greyish green to blue-green, slender, up to 15 cm long. The flowers are produced singly or up to five together in a cyme; they are 3–5 cm diameter, and sweetly scented; the original natural flower colour is bright pinkish-purple, but cultivars of other colours, including red, white, yellow and green, have been developed.

Carnations require well-drained, neutral to slightly alkaline soil, and full sun. Numerous cultivars have been selected for garden planting. Typical examples include 'Gina Porto', 'Helen', 'Laced Romeo', 'Red Rocket'.

Colombia is the largest carnation producer in the world.

For the most part, carnations express love, fascination, and distinction, though there are many variations dependent on colour.

The formal name for carnation, dianthus, comes from Greek for "heavenly flower", or the flower of Jove.

Carnations are often worn on special occasions, especially Mother's Day and weddings. In 1907 Anna Jarvis chose a carnation as the emblem of Mother's Day because it was the favourite flower of her mother. This tradition is now observed in the United States and Canada on the second Sunday in May. Ann Jarvis chose the white carnation because she wanted to represent the purity of a mother's love. This meaning has evolved over time, and now a red carnation may be worn if one's mother is alive, and a white one if she has died.

In Korea, red and pink Carnations are used for showing their love and gratitude toward their parents on Parents Day (Korea does not separate Mother's Day and Father's Day, but has Parents Day on May 8). Sometimes, you can see parents wear a corsage of Carnation(s) on their left chest on Parents Day. Not only on Parents Day, but also on Teacher's Day (May 15), people express their admiration and gratitude to their teachers with Carnations, as Carnation has the meaning of 'admiration', 'love', and 'gratitude'.

Red carnations are worn on May Day as a symbol of the labor movement in some countries, such as Austria, Italy, and successor countries of former Yugoslavia. Red carnation is also the symbol of the Portuguese Carnation Revolution.

Green carnations are for St. Patrick's Day and were famously worn by the Irish writer Oscar Wilde. The green carnation thence became a symbol of homosexuality in the early 20th century.

At Oxford University, carnations are traditionally worn to all examinations; white for the first exam, pink for exams in between and a red for the last exam. Originally this was a white carnation that was kept in a red inkpot between exams, so by the last exam it was fully red. It is thought to originate in the late 1990's.