Herb to Know: Soapwort

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Photograph by J. G. Strauch, Jr.

Saponaria officinalis
• (sap-uh-NAIR-ee-uh off-iss-ih-NAL-iss)
• Family Caryophyllaceae
• Hardy perennial

Here’s a tough and beautiful herb with an unusual feature: soapsuds. The Assyrians made a soap from it as far back as the eighth century b.c. Later, European woolen mills used it for shrinking and thickening woven cloth, and soapwort plants still mark the sites of the old mills. Today, even with the plethora of synthetic cleaning agents available, conservators choose soapwort as a gentle cleanser for valuable antique fabrics, furniture, and pictures. Apart from their use as a cleanser, the suds also gave early Pennsylvania Dutch beers a foamy head.

The genus Saponaria comprises about twenty species of perennial herbs native to Europe and southwestern Asia. S. officinalis is probably ­native to western Asia, but it has been grown in European gardens for centuries both for its soap and for medicinal purposes. It is naturalized throughout the United States and Canada in sunny fields and along railroads and roadsides.

Clumps of robust, erect 3-foot stems arise from thick white underground rhizomes. Smooth, lance-shaped opposite green leaves with pointed tips and three prominent veins are borne on short stalks. They measure 2 to 3 inches long by 1/3 inch wide. Loose clusters of ­1-inch-wide, showy pink or whitish flowers bloom in mid- to late summer. Each flower has a long, cylindrical green calyx, five petals that are narrowed at the base, ten stamens, and two styles. Odorless in daytime, they emit a clove scent at night which attracts moth pollinators. Maud Grieve, author of A Modern Herbal (1931), noted “a bitter and slightly sweet taste, followed by a ­persistent pungency and a numbing sensation in the mouth”. The fruit is a four-toothed capsule.

Double forms such as the one shown here can be found growing wild. Both the single and double forms are attractive in the garden in the middle or back of the border. The light pink flowers go well with almost everything, and the green foliage contrasts nicely with ferny gray artemisias or yarrows or the fine green foliage and blue flower spikes of hyssop, for example.

The generic name Saponaria comes from the Latin word sapo, “soap”. Common names that allude to the plant’s soapiness include latherwort, fuller’s herb, and lady’s-washbowl. Officinalis means “from the (druggist’s) storeroom” and refers to its medicinal uses, as does the alternate common name bruisewort. The names old-maid’s-pink and wild sweet William seem to acknowledge the flowers’ resemblance and close relationship to pinks (Dianthus spp.). The perplexing (but common) name bouncing Bet may be soap-related, too, supposedly coming from the fact that barmaids (generally called Bet or Betsy) used leafy stalks to scour beer bottles in old England. Whether the barmaids, leaf stalks, or bottles bounced is unclear. Jo Ann Gardner, in The Heirloom Garden (1992), considers the name an apt description of the way the plant “moves about by way of its creeping roots”.

Medicinal Uses For Soapwort

Culpeper called soapwort “an abso­lute cure in the French pox [syphilis]”, and Mrs. Grieve called it a valuable remedy for syphilis or other venereal diseases. It has also been used internally to treat gout, liver disorders, rheumatism, skin diseases, constipation, and bronchial congestion, and to promote urination. None of these uses has been supported by scientific research, however. Saponins (the lather-forming ­constituents) are very irritating to the digestive system, and large quantities may cause severe vomiting and diarrhea, destroy red blood cells, and paralyze the part of the nervous system that controls the diameter of the blood vessels. Livestock that eat hay containing soapwort plants may be poisoned by the seeds. Roots and foliage that touch pond water may poison fish.

Soapwort is relatively safe to use externally. Juice from the leaves or roots has been used to relieve the itching and/or irritation of many skin disorders including poison ivy, acne, eczema, psoriasis, and boils. A root decoction poulticed on a black eye is said to remove the discoloration. If you decide to use the lather to shampoo your hair, keep it out of your eyes, as it can cause severe irritation.

Growing Soapwort

Soapwort is hardy in USDA Zones 2 through at least 8. Set plants a foot apart in average to poor well-drained soil in full sun to light shade. Sow seeds outside in spring or fall or indoors in late winter. Deadhead to encourage repeat blooms and prevent self-sowing. Soapwort can be invasive in moist, rich soil. Propagate by seed, division, or softwood cuttings taken in summer. The double forms come fairly true from seed, but you’ll probably get some single-flowered plants, too.

Harvest leafy stems in summer, rhizomes in late autumn. Dry both for making soap. Boil the chopped roots or tops in water for about five minutes, or just steep them in water for a few hours, then agitate the water to make a lather.


• Forestfarm, 990 Tetherow Rd., Williams, OR 97544-9599. Catalog $3. Soponaria officinalis ‘Alba Plena’, S. o. ‘Flore-Pleno’. Plants.
• Milaeger’s Gardens, 4838 Douglas Ave., Racine, WI 53412-2498. Catalog $1. S. o. ‘Flore-pleno’. Plants.
• Richters, Goodwood, ON, Canada L0C 1A0. Catalog free. S. officinalis. Seeds.
• Sandy Mush Herb Nursery, Rt. 2, Surrett Cove Rd., Leicester, NC 28748. Catalog $4. S. officinalis. Plants, seeds.
• The Thyme Garden, 20546 Alsea Hwy., Alsea, OR 97324. Catalog $2. S. officinalis. Plants, seeds.
• André Viette Farm and Nursery, Rt. 1, Box 16, Fishersville, VA 22939. Catalog $6. S. o. ‘Rubra Plena’. Plants.

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