Soapweed Yucca — May 2009

yucca plant

     On March 14, 1927, the yucca was officially declared as the state flower of New Mexico citing this plant as a symbol of sturdiness and beauty.  Indeed yuccas are among the iconic plants of the American Southwest and their historic and cultural significance make them an excellent choice as a state symbol.  Unlike most other state flowers, however, a particular species of yucca was not designated so any of the 11 native yucca species qualify as our state flower.  This essay focuses on Yucca glauca, one of the two species (Yucca baccata, the banana yucca, is the other) that are prevalent on the Preserve.  Yucca is derived from the Carib name for cassava, the tropical plant from which tapioca is made but which is botanically completely unrelated to yuccas.  Somehow the same name was inappropriately applied to the plants known as yuccas today, and that usage became so widespread that the local name yuca was used as the basis for the plant’s scientific name.  The specific epithet, glauca, describes the bluish-green, powdery coating on the surface of the leaves.  

     Yucca glauca is known by the common names soapweed yucca, plains yucca, narrowleaf yucca, Spanish bayonet, beargrass, and "lamparas de dios” (lamps of the Lord).  It is a perennial evergreen shrub with a short, stubby, mostly underground stem.  A starburst of many long thin leaves with sharp tips emerges from the top of the stem.  Individual leaves may be up to two feet long and about 1/2” wide with a flat upper surface and a convex back surface.  The leaf edges are often whitish with curled filaments.  Soapweed yucca has thick roots capable of growing side branches that become new plants.  This type of vegetative reproduction results in clumps of yuccas scattered over our sandy plains and other open areas.

yucca flowering plants

     Flower stalks grow from the center of the leaf cluster and may extend up to three feet high.  Dozens of large fleshy somewhat bell-shaped flowers open along the stalk in the late spring.  Each flower has three petal-like sepals with varying degrees of purple color and three slightly wider petals that are typically ivory to white.  The center of the flower is made up of six sepals surrounding a pistil with a three-chambered ovary.   

yucca flower

     Yuccas have a most interesting relationship and highly specific with their moth pollinators.  The female yucca moth will visit a flower and collect a mass of pollen grains with its specializedmouthparts (yuccas, unlike most flowers, do not release individual pollen grains).  The moth will fly off with its wad of pollen, find another yucca flower and deposit an egg in the flower’s ovary.  Then she will climb to the tip of the pistil and push the mass of pollen into the cup-like stigma.  Successful pollination will lead to the development of dozens of seeds within the ovary.  When the moth egg hatches, the larva feeds on some of the developing seeds, but most of the seeds continue their development and are later released from a three-part seed capsule.  This highly specific symbiotic relationship allows both species to flourish.  Indeed, when yuccas, which are native to the New World, are grown in the Eastern Hemisphere where there are no yucca moths, growers must hand pollinate their plants to get seeds. 

yucca seed pods

     Yucca and Agave are the two genera of the family Agavaceae native to New Mexico.  This family is characterized by plants that produce a rosette of fibrous basal leaves surrounding a central flowering stalk.  Members of this family have clearly long been important to indigenous peoples, as evidenced by the fact that such plants are represented in some petroglyphs.  The fibers from their leaves and flower stalks were useful in basketry, rope-making, thatching and for producing paintbrushes, headdresses, belts, mats, and footwear.  Flowers, young flower stalks, and fruits were all eaten either raw or cooked.  Roots were used to produce soap and shampoo.  A decoction from roots treated hair loss, stomachaches, skin irritations, and bleeding cuts.

     Yuccas remain useful to people today, particularly in the production of fibers and soaps.  They are even more useful to local wildlife as food; in fact our longhorns are so fond of the flowers and fruits that intact yucca flower stalks are pretty hard to come by on the Preserve.  Various birds and small mammals also use dead yuccas either as nesting sites or a source of nesting materials.  Yes, yuccas are unquestionably sturdy and beautiful, certainly sufficient reason for their selection as our state flower; but in my view the utilitarian value of yuccas make their choice even more appropriate for a state in which the ability to survive by using natural materials is such an essential aspect of our past heritage and present lifestyle.

For a printable pdf of this essay, click here.

© 2009 Jerry Melaragno

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