Soapwort, crow soap, soapweed, lather root, our ancestors named Saponaris officinalis, for its use as a soap. All it took was a quick trip to the garden to gather some leaves which were boiled to make a liquid soap that could be used to wash people and clothing. Both the leaves and the roots contain saponin, which creates a lather when added to water. It has been used to produce the “head” on beer.
The boiled leaves and roots of the soapwort plant results in a cleanser that can remove fats and grease but is so mild that even today, museums use soapwort to clean delicate textiles.
Soapwort should not be eaten. In large quantities can induce vomiting and diarrhea. It is not harmful in small quantities and is, in fact, used in the manufacture of halvah, a Middle Eastern sweet.
Soapwort is also known by names that were descriptive of the occupations that used it. “Bouncing Bet” was a term for a washerwoman. “Fuller’s herb” described the process of washing finished woolen cloth also known as “fulling”.
Soapwort is a herbaceous perennial hardy in zones 4 through 10. It is native to the temperate zones of Europe and Asia. The European colonists brought it with them to North America where it has thrived. It likes full sun and well-drained soil. Too much moisture will send it into rapid decline. Mature plants are 2 to 2 ½ feet tall with pink or occasionally white flowers that resemble Sweet William from which another of its common names, Wild Sweet William, derives. The flowers open in the evening and are very fragrant making them an excellent addition to a Moon Garden. Bloom time is from May to September.
Soapwort can become invasive spreading by underground rhizomes. Unless you are harvesting the roots to make soap, it is recommended that you plant soapwort either in containers or use barriers around the plants to prevent the rhizomes from spreading.
Soapwort is easily grown from seed. The seed can be direct sown in your garden in the spring after the soil has warmed to at least 65°F. Press it firmly into the soil and then lightly cover it. You can expect germination in 2 to 3 weeks. Or you can start your seeds indoors and plant the seedlings outside after all danger of frost has passed. Keep the seedlings evenly moist.
Making soap with soapwort is very easy. Simply pick some leaves, bruise them or chop them and then boil for 30 minutes. Cool the liquid and strain out the leaves. The roots can also be boiled or you can dry the roots and grind them up to use like a soap powder.
Roots should be harvested in the fall. If your clump of soapwort is getting over crowded, pull up every third plant. This will give your plants some breathing space and give you roots and leaves to make into soap.