Plants perennial, colonial. Stems erect, simple or branched distally, 30-90 cm. Leaves: petiole often absent or winged, 0.1-1.5 cm; blade strongly 3(-5)-veined, elliptic to oblanceolate or ovate, 3-11(-15) × 1.5-4.5 cm. Cymes dense to open. Pedicels 1-5 mm. Flowers sometimes double; calyx green or reddish, often cleft, 15-25 mm, glabrous or rarely with scattered trichomes; petals pink to white, often drying to dull purple, blade 8-15 mm. Capsules ca. 15-20 mm. Seeds 1.6-2 mm wide. 2n = 28. Flowering spring-fall. Waste places, streamsides, fields, roadsides; 0-2600 m; introduced; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Eurasia; introduced in Mexico, South America, Asia (India), Africa (Egypt), Australia. Saponaria officinalis, long cultivated for its showy flowers, is a widely naturalized, sometimes troublesome weed. It may persist for years about abandoned home sites. 'Double'-flowered horticultural forms, which may lack functional stamens, also occur in the wild, where locally they may be as common as, or even more common than, 'single'-flowered forms.

In former times, the leaves of this species were gathered and either soaked or boiled in water, the resulting liquid being used for washing as a liquid soap. Because of its saponin content, the species can be poisonous upon ingestion, in much the same manner as Agrostemma githago.

Plant: Perennial forb to 1 m; stems numerous Leaves: leaves opposite and clustered at nodes, lance-ovate 4-8 cm long, sessile, strongly-veined INFLORESCENCE: cymes at branch tips Flowers: flowers pink-purple, fragrant, tubular, ~3 cm long Fruit: a many-seeded capsule; Seed 1.5-2 mm, ± spheric, notched, ± compressed, tubercled Misc: Roadsides, oak woodlands, streambeds, disturbed areas; < 1500 m.; Jun-Sep