Soap Plant

Soap plant
Soap Plant © KKorbholz

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 Family (Agavaceae)
  • Perennial herb
    • 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 (branching stem with flowers opening from the bottom up)
    • 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 (San Mateo County Parks prohibits removal of any natural material)

  • Wildlife
    • Deer will eat the emerging tender leaves in early spring; look for clipped leaf tips
  • Native people
    • Food
      • Before flowering, young shoots were harvested, roasted, and eaten
      • Bulbs were boiled or roasted to remove soapy taste, then eaten like a potato
    • Medicine
      • Fresh bulb was rubbed on the body for cramps and for rheumatism
      • Decoction of the bulb used as a diuretic and laxative, and for stomach ache
    • Other uses
      • Bulbs used for fishing
        • Crushed bulbs were mixed with water to create suds, then thrown in slow-moving creeks or pools to stun fish, aiding in their capture
        • Soap-like saponins in the bulbs enter through the gills and interfere with oxygen absorption and transport (Rosenthal 2014)
        • Roots of California manroot (Marah fabacea) and the fruits of California buckeye (Aesculus californica) and common snowberry (Symphoricarpos albus var. laevigatus) were similarly used for fishing
      • 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, rhizomes, or enlarged taproots) are well 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
Soap Plant (L), Fremont’s Star Lily (R)
© SBernhard

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
    • 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

At Edgewood

  • Found in all habitats, including serpentine grasslands
    • See iNaturalist for observations of 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 W. Roderick. 2006. Soaproot Chlorogalum pomeridianum (D.C.) Kunth. Plant Guide. United States Department of Agriculture, Natural Resources Conservation Service, National Plant Data Center c/o Plant Science Department, University of California, Davis, California.

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

Rosenthal, S. 2014, Jan. 13. The many uses of spring-blooming soaproot. Bay Nature.

van Doorn, W.G. and U. van Meeteren. 2003, Aug. 1. Flower opening and closure: A review. Journal of Experimental Botany 54: 1801-1812. Oxford Academic.