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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where the plant may be found. Chlorogalum pomeridianum range map. USDA PLANTS Database.

Chlorogalum pomeridianum. Soap plant (Chlorogalum pomeridianum). Photo by Gladys Lucille Smith, California Academy of Sciences.

Chlorogalum pomeridianum. Soap plant (Chlorogalum pomeridianum). Photo by Brother Alfred Brousseau © 1995 Saint Mary's College of California.

Chlorogalum pomeridianum. Soap plant (Chlorogalum pomeridianum). Photo by J.S. Peterson, Smithsonian.

Chlorogalum pomeridianum. Soap plant (Chlorogalum pomeridianum). Photo by J.S. Peterson © USDA-NRCS PLANTS Database.

Soap Plant (Chlorogalum pomeridianum (DC.) Kunth)

By Forest Jay Gauna, Modoc National Forest

Chlorogalum pomeridianum, called “wavyleaf soap plant,” “soap root,” or “amole,” is a low-growing plant of California and Oregon. It is used as soap by the local peoples. The generic name Chlorogalum means “green milk,” and refers to the green juice exuded by a broken leaf. The specific epithet pomeridianum is more interesting: it derives from post meridiem, or “past mid-day,” the Latin phrase which gave rise to our abbreviation “p.m.” This refers to the flowers, which flower late in the day.

Soap Plant is easy to recognize in the wild. It has characteristic light-green, wavy-edged leaves, linear, from one to two feet long. A member of the Liliaceae or lily family, the flower has six white tepals (that is to say, petals and sepals that look alike) each with a green midvein, six yellow-tipped stamens, and a style. Nectar is secreted at the base of the tepals, and seems to be enjoyed by bumblebees. The entire flower is about ½ to 1 inch wide and radial. The flower opens in the evening (vespertine) quickly; after being open all night, the tepals wilt and liquefy, and dry into little remnants during the following day. The inflorescence upon which the flowers are borne is easy to recognize. It is spindly, much branched, and tall (to 6 feet or more). A flowering plant is to be respected: it takes about 10 years for a plant to grow from seed to flower. The bulb of the plant is also easily recognized: a brown, fibrous bulb a little larger than a person’s fist, with a white, pliable heart. When crushed, this heart yields soap. Interestingly, a few contractile roots emerge from the bulb every year, and pull the bulb down into the earth.

Amole is a generic Spanish term for a plant-derived soap; other plants of the Southwest have this name. Sources say that it makes excellent laundry soap for delicate fabrics, good shampoo, dish detergent, and bath soap. The brown fibre that is stripped off the bulb is made into little brushes. The boiled bulb makes a kind of glue. This is truly a plant of great utility.

Besides the above listed uses, the local Native Americans also used the bulb for food. The soapy root contains toxins that stupefy fish, causing them to float to the surface of the stream or pond where the root is applied; this technique, however, is in modern times not legal. The bulb itself is also eaten; it is cooked in an old-style earthen oven for a good period (overnight, for instance), and becomes sweet and good for food. Like so many of the other plants known to the California natives, this plant was used also for medicinal purposes.

Be careful using this plant if you are not familiar with it. Eating the bulb raw is bad, for the same chemicals that make it a good soap and fish poison (saponins) are present in the raw bulb.

Thanks to Judy Jernstedt, whose help was invaluable for this Plant of the Month write-up.

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