Saponaria (commonly known as soapworts) is a genus of flowering plants in the family Caryophyllaceae. It is usually characterized by pink or white flowers.
The plants are herbaceous perennials and annuals, some with woody bases. The flowers are abundant, five-petalled and usually in shades of pink or white.
The genus is closely related to the genus Silene, being distinguished from these by having only two (not three or five) styles in the flower.
It is also related to Gypsophila, but its calyx is cylindrical rather than bell-shaped.
The most familiar species might be common soapwort (S. officinalis), which is native to Eurasia but is known in much of the world as an introduced species, often a weed, and sometimes a cultivated ornamental plant.
There are thirty to forty species in the genus overall.
Plants of the World Online accepts 39 species:
The genus name Saponaria derives from the Latin ("soap") and -aria ("pertaining to"), with at least one species, S. officinalis, being used to make soap.
Saponaria species are eaten by the larvae of some butterflies and moths, including the Lychnis and Coleophora saponariella, which is exclusive to the genus.
The plants contain saponins and a liquid soap can be produced by soaking the leaves in water. This soap is still used to clean delicate antique tapestries.