Soap Plant

Soap plant
Soap Plant © KKorbohlz

Common Soaproot, Wavyleaf Soap Plant, Amole
Chlorogalum pomeridianum var. pomeridianum
NATIVE

Description (Jepson, PlantID.net)

    • Monocotyledon
      • Monocots are a major lineage of flowering plants; see family for general characteristics
    • Agave / Century Plant Family (Agavaceae)
    • Perennial herb
    • Geophyte (plant with an underground storage organ)
      • Grows from a bulb (short underground stem with fleshy leaves, e.g. onion)
    • Leaves
      • Arranged in a basal rosette
      • Long and narrow (1 in. wide and ≤ 20 in. long)
      • Usually wavy-edged
    • Flowers
      • Inflorescence (flower arrangement) is a single, tall panicle (a many-branching, loose flower cluster)
      • White, fragrant flowers
      • Narrow, recurved “petals” are actually 3 petals and 3 sepals (outer flower parts) in 2 separate whorls, similar in appearance and collectively called tepals
      • Long, yellow-tipped stamens (male flower parts)
      • Ovary superior (above the attachment of other flower parts)
    • Height to ~8 ft.
    Bulb © DSchiel

    Distribution

      • Native to California
        • Grows in a variety of habitats, including in annual grasslands, coastal sage scrub, chaparral, oak woodlands, low-elevation conifer forests, and mixed-evergreen forests
        • See Calflora for statewide observations of this plant
      • Of the 3 recognized varieties, this variety grows only slightly beyond California borders into southwestern Oregon; other 2 varieties only grow in California
      • Grows at elevations to 4,900 ft.

      Uses (Picking or removing any natural material from public land is illegal)

        • Deer will eat the emerging tender leaves in early spring; look for clipped leaf tips
        • Native people had many uses for soap plant
          • As food
            • Young shoots were harvested before flowering, roasted, and eaten
            • Bulbs were boiled or roasted to remove soapy taste, then eaten like a potato
          • As medicine
            • Fresh bulb was rubbed on the body for cramps and for rheumatism
            • Decoction of the bulb acted as a diuretic and laxative, and for stomach ache
          • Other uses
            • Crushed bulbs, which contain toxic saponins, were thrown into water to aid in the capture of fish: saponins interfere with the functioning of gills, killing or incapacitating the fish (Eeckhaut 2015)
            • Crushed bulbs were used as soap
            • Fibers around bulb were made into brushes
            • Gummy substance in bulb was used as glue
            • Leaves used by Sierra Miwok to make dolls
        Seeds © DSchiel

        Name Derivation

        • Chlorogalum (klor-OG-al-um) – from the Greek for “green milk” or “juice”
          • pomeridianum (pom-er-id-ee-AY-num) – from the Latin for “of the afternoon” (post-meridian), because flowers open in the afternoon

          Notes

            • Flowers pop open in the late afternoon; watch closely and you can see it happen!
              • Each flower remains open all night, after which the flower wilts and dries, leaving a little remnant the next day
              • This process is an example of nyctinasty, which refers to diurnal and nocturnal changes (single or repetitive) exhibited by the leaves and flowers of some plants (van Doorn 2003)
            • Pollinated during the afternoon by large bees (honey bees, carpenter bees, and 2 species of bumblebee) and, after dark, by sphingid moths
            • Geophytes, e.g. plants growing from bulbs, corms, and rhizomes, are adapted to survive fire, our Mediterranean climate’s long, dry summers, and extended droughts
              • Above-ground growth dies back after flowering, while underground the plant survives with stored water and nutrients
            • Watch for fibrous bulbs sticking out from eroded trails and banks
              • Soap plant has contractile roots that pull the bulb deeper underground throughout the plant’s life
              • Thus the bulb becomes increasingly protected from fire as the plant ages
            • Takes 5-7 years before producing its first flowers
            • Native people actively managed soap plant and other edible geophytes (Anderson 2005)
              • Hardwood sticks were used for digging
              • Some plants were spared to allow future crops
              • Bulblets were dispersed and replanted
              • Areas were burned to decrease competition and recycle nutrients
            • Edgewood’s soap plant is classified as a variety
              • Subspecies rank is used to recognize geographic distinctiveness, whereas variety rank is appropriate for variants seen throughout the geographic range of the species; in practice, these two ranks are not distinct
            Wavy Leaves © KKorbohlz

            ID Tips

              • May be confused with Fremont’s star lily (Toxicoscordion fremontii)
                • Soap plant
                  • Has wavy leaves, matte on upper surface, blue-green in maturity
                  • Whorl of leaves is not strongly triangulate at the base
                  • Flowers in late spring/early summer
                  • Deer often heavily browse the tender new leaves
                • Fremont’s star lily
                  • Has straight-edged, shiny, bright green leaves
                  • Whorl of leaves has a strongly triangulate base (you can feel it!)
                  • Flowers in early spring
                  • Deer tend not to eat the fresh leaves because of plant toxicity

              At Edgewood

                • Found in all habitats
                  • See iNaturalist for observations of this plant
                    • Note observations are for Chlorogalum pomeridianum
                • Flowers May – June

                See General References

                Specific References

                  Anderson, M.K. 2005. Tending the Wild. University of California, Berkeley.

                    Anderson, M.K. and Roderick, W. 2006. Plant Guide: Soaproot. U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS), National Plant Data Center.

                      Eeckhaut, I., et al. 2015, June. Effects of Holothuroid Ichtyotoxic Saponins on the Gills of Free-Living Fishes and Symbiotic Pearlfishes. University of Chicago. Biological Bulletin, 228:3.

                        Fryer, J.L. 2015. (Revised from Reeves, S.L. 2006.) Chlorogalum pomeridianum. Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

                          van Doorn, W.G., and van Meeteren, U. 2003, Aug. 1. Flower opening and closure: a review. Journal of Experimental Botany, Volume 54, Issue 389, pp.1801–1812.