Soapweed/Yucca

General Information

• Plants: With its dense clump of sharply pointed, stiff basal leaves yucca is unmistakable. The stiff, narrow leaves are blue-green and glaucous (covered with a fine powdery substance that rubs off).
• Flowers: The flowers are large (2-inch long), with 6 broad floral tepals (petals and petal-like sepals) and 6 stamens.
• Fruits: Large, woody pods about 2 inches long.
• Flowering Season: May–July.
• Habitat/Range: Sandy, well-drained sites; valleys, and foothills in Alberta, Montana and North Dakota south to New Mexico and Texas.¹

Blackfeet Ethnobotany^*

by Darnell and Smokey Rides At The Door

The Blackfeet name for soapweed yucca is Aik Sik Koo Ki. It translates to 'sharp plant' after the plant's appearance and the pointed tips of the leaves. Traditionally used most often as a tea or a poultice for both human and horse ailments. Applying chewed roots to sprains, breaks, bleeding cuts, or saddle sores on horses all were uses of the plant as a poultice. Horses upon their reintroduction to the continent quickly became highly respected, valued, and honored as wealth by the Blackfeet. A steam of soapweed yucca was sometimes given to horses. It also was used as a hair tonic and soap due to the soap-like qualities of the plant.²

From the Journals

by H. Wayne Phillips

In his journals for September 2, 1804 Clark described in detail what he believed were ancient military fortifications, which today we believe are natural sand-ridges.³ Clark noted that their hunters:

Killed four fat Elk on the Isld. We had them Jufked [jerked for drying] & the Skins Stretched to Cover the Perogues [open boats] water riseing, I observe Bear grass & Rhue in the Sides of the hills at Sunset the [wind] lulled and cleared up cool—Aired the meet [meat] all in high Spirits.⁴

Clark's "Bear grass" was a common name for a different species of yucca which is what he was possibly describing, and by "rhue," Clark was referring to sumac (Rhus species). Both plants are common today around Lewis and Clark Lake. However, there is no explicit journal entry that can be definitively linked to soapweed yucca. It would not be scientifically documented until 1811.

Additional Information: Pollination of yucca flowers is an incredible example of symbiosis, meaning a mutually beneficial relationship, involving a plant and an insect. Yucca moths, Pronuba yuccasella (but also some other smaller insects, Pseudocalliope spp.), pollinate the plant completely. Neither organism would survive without the other; the yucca moth lays its eggs inside the plant, and as a result, the plant is pollinated. By pollinating the new plant, the yucca moth ensures its offspring have a reliable food source when the eggs hatch. The soapy lather that is formed from crushing roots and combining with water is due to a naturally occurring compound called saponin.⁵

There are 40 species of yucca, all considered native to North America.⁶

^*While traditional medicine is still practiced in many cultures including the Blackfeet culture and has many uses, please do not consume any plant material without consultation of a health professional.