In the northern states including Illinois, it is grown as a garden annual reaching 12-18 inches tall . In the south, from Florida to California, it grows as a perennial shrub of 3-6 feet tall. In the tropics, it may grow even taller.
Leaves are aromatic when crushed.
Flowers are borne in dense clusters 1-2 inches across on the axils near the top of the stem. Often, the different colored flowers are present on the same cluster.