mostly perennial Old World herbs

Saponaria, also known as soapwort, is a genus of about 20 species of perennial herbs in the Caryophyllaceae, native to southern Europe and southwest Asia. They grow to a height of 10-60 cm, with opposite leaves 1-6 cm long. The flowers are produced in tight clusters on the stem, 4-25 mm diameter, with five white, yellow, pink, or pale purple petals.