saponaria

Saponaria is a genus of flowering plants in the family Caryophyllaceae, commonly known as soapwort. It includes several species native to Europe, western Asia, and northern Africa, with Saponaria officinalis (common soapwort) and Saponaria ocymoides (rock soapwort) among the best known.

Description: These are herbaceous perennials or annuals with opposite leaves and slender stems. Leaves are simple and the flowers are five-petaled, often pink, white, or rosy, arranged in branched clusters at the ends of flowering stems. Flowers typically bloom from late spring to summer and are attractive to bees. Some species are evergreen or semi-evergreen in mild climates.

Chemistry and uses: All parts of the plant contain saponins, surface-active glycosides that foam when shaken in water. Historically, crushed soapwort was used as a gentle soap substitute for washing delicate fabrics and wool. In modern times its primary value is ornamental, though ingestion of significant quantities can be toxic.

Cultivation and distribution: Saponaria species are grown in herbaceous borders, rock gardens, and as ground covers (notably S. ocymoides). They prefer full sun and well-drained soil and are generally drought-tolerant once established. Propagation is by seed or division in spring. Some species can naturalize beyond cultivation in suitable climates.

Taxonomy and notes: The genus Saponaria is within Caryophyllaceae and is related to other ornamentals such as Dianthus and Silene. The name derives from the soap-like properties of the plant.