Also called Bouncing Bet, this cheerful pink  came over as a garden flower, but is now thoroughly established along roadsides and at the edge of the woods; this plant was growing against a tombstone in an overgrown cemetery in Beechview, where it was blooming in the middle of July. The flowers are very pale pink verging on white; the double forms Gray mentions seldom or never occur in the wild plants seen around Pittsburgh. The name “Soapwort” reminds us that a lathery soap can be made from the plant; it is, however, poisonous.

Gray describes the genus and the species:

SAPONARIA L. Calyx narrowly ovoid or subcylindric, 5-toothed, obscurely nerved, naked. Stamens 10. Styles 2. Pod 1-celled, or incompletely 2-4-celled at base, 4-toothed at the apex. — Coarse annuals or perennials, with large flowers. (Name from sapo, soap, the mucilaginous juice forming a lather with water.)

S. officinalis L. (SOAPWORT, BOUNCING BET.) Flowers in corymbed clusters; calyx terete; petals crowned with an appendage at the top of the claw; leaves oval-lanceolate. — Roadsides, etc. July-Sept. — A stout perennial, with large rose-colored flowers, commonly double.  (Adv. from Eu.)

–

In How to Know the Wild Flowers (1909), Mrs. Dana gives us this description of the plant:

BOUNCING BET. SOAPWORT.

Saponaria officinalis. Pink Family.

Stem.—Rather stout; swollen at the joints. Leaves.—Oval; opposite. Flowers.—Pink or white; clustered. Calyx.—Of five united sepals. Corolla.—Of five pinkish, long-clawed petals (frequently the flowers are double). Stamens.—Ten. Pistil.—One, with two styles.

A cheery pretty plant is this with large, rose-tinged flowers which are especially effective when double.

Bouncing Bet is of a sociable turn and is seldom found far from civilization, delighting in the proximity of farm-houses and their belongings, in the shape of children, chickens, and cattle. She comes to us from England, and her “feminine comeliness and bounce” suggest to Mr. Burroughs a Yorkshire housemaid. The generic name is from sapo—soap—and refers to the lather which the juice forms with water, and which is said to have been used as a substitute for soap.