Soaptree yucca

  • Soaptree yucca in from of Monument to the Last Horse.
  • Soaptree blooms
  • Soaptree yucca near Irwin installation.

One of Marfa Plateau’s most familiar plants is the soaptree yucca (Yucca elata), which boasts leaves that are long, green and spiky. Although the base plant is very slow growing, something quite different happens in early summer, when the yucca sends up a stalk that can grow several inches in a day. At the end of this stalk are rows of ivory-colored, bell-shaped flowers. The yucca stalk can grow to be 20 feet tall!

The soaptree yucca’s waxy flowers emit a pleasantly sweet vanilla scent that is most notable at night. Why do you think it’s called the soaptree? These plants have a foamy compound called saponin in their roots and trunks. Indiginous Americans discovered that when the saponin is harvested and agitated with water, it can be used as soap. Almost every part of this yucca has been utilized by humans: the stiff leaves can be woven for baskets; the fibers of the leaves and the pointy ends can be pulled apart and used as a needle and thread; the roots, flowers and seeds may be consumed for nutrition or made into medicine and, once they’ve dried, the long stalks are a building material in the treeless desert.

A fascinating aspect of this plant is the symbiotic relationship it shares with the yucca moth. The soaptree’s flower is long and narrow and there’s only one creature on the entire planet that can pollinate it. That’s the yucca moth! Without this moth, the yucca plant can’t reproduce and make more yuccas. In turn, the yucca moth does not gather pollen from any other plant. The female moth gathers pollen under her head and travels to another flower to lay her eggs. After laying, she combs the pollen into the plant’s stigma, deep inside the flower, which ensures that a pod with seeds will develop. That seed pod hardens and serves as a protective house with a food source inside for the moth larvae. Unbelievable!

Many plants, like yucca, have lots of uses. Research other plants that have various uses and select one that sparks your interest. Learn more about what it can be used for (eating? Medicine? To make clothing?), or what it was used for in the past. Draw a detailed illustration of this plant and record your findings next to your drawing.