Yuccas (Spanish Bayonet; Soapweed)

Photo of soapweed, a type of yucca
Safety Concerns
Scientific Name
Yucca smalliana, Y. glauca, and Y. arkansana
Agavaceae (agaves)

Three species of yucca may be found growing wild in Missouri. Spanish bayonet was introduced from the Southwest and has escaped from cultivation, but our other two yuccas are native.

Spanish bayonet, or Adam’s needle (Yucca smalliana; formerly Y. filamentosa or Y. flaccida), has stout, scaly flower stalks topped by a panicle of many flowers, arising above a large basal cluster of stout, sharp-pointed, leathery leaves. The flowers are cuplike, with 3 sepals and 3 petals, 2 inches across, and creamy white. Blooms May–July. Leaves are basal, stiff, narrow, sharply pointed, to 2½ feet long, often with fibrous edges. Fruit is a large, papery capsule with hundreds of flat, black seeds.

Soapweed, or soapweed yucca (Yucca glauca), is a native that, in Missouri, is found only in the northwestern corner of the state (Holt and Atchison counties). The base of the flowering portion of the flower clusters is not raised above the leaves, and the leaves are spine-tipped.

Another soapweed, sometimes called Arkansas yucca (Y. arkansana), is a native that in our state is found only in the southern portion of Missouri’s Ozarks, along the Arkansas border. It is similar to Y. glauca, but it has softer leaves that are not spine-tipped.

Other Common Names
Adam’s Needle

Height: to about 7 feet (flowering stalk).

Where To Find
image of Yuccas Spanish Bayonet Soapweed Adams Needle Distribution Map

Spanish bayonet is scattered statewide. Our two native soapweed yuccas are restricted to northwestern counties (Y. glauca) and to southern counties (Y. arkansana).

Spanish bayonet occurs on roadsides, railroads, abandoned homes, and gardens. It is native to the southwestern United States, introduced here and escaped from cultivation.

Of our two native soapweeds, Y. arkansana is found in glades, open rocky woods, and roadsides, and Y. glauca is uncommon, for it is restricted to the few remaining loess hill prairies in the state.

Missouri's most common yucca, Y. smalliana, may also be called Y. filamentosa, Y. filamentosa smalliana, or Y. flaccida. Different botanists have interpreted the relationships of these plants in different ways.

Yuccas are tremendously useful. The roots of some species have been used in soapmaking (thus the name "soapweed"), and the seeds have been eaten raw, roasted, or ground into a flour. The tough leaves provide fiber for cordage and broom-making. Yuccas have also been used medicinally. Today, yuccas are valued by landscapers.

Spanish bayonet is abundant enough in some localities to be seriously used as a wild edible. First, be advised that some people are sensitive to some species of yucca and should not eat them raw. If you're concerned, sample a single petal at first and wait for about half an hour. A sore throat or upset stomach is a sign you should only eat these cooked. Many people, however, have no ill effects from eating the raw flower petals. The flower petals are good in salads and are especially pretty when used with rose and violet petals. The flowers can also be breaded and fried as fritters (you can find several specific recipes online), or you can sauté them or add them to stir-fries or omelets. Many recipes recommend removing the pistils and other reproductive parts of the flower (which may be bitter) and just using the petals. The tender young flower stalks, as they are just rising from the basal leaves, can be cooked and eaten like asparagus.

In Mexico and elsewhere in Central America, yucca flowers are used in several tasty dishes.

Yuccas and agaves have been used by New World people in many ways throughout history, particularly in the Southwest. Ethnobotany is a fascinating and useful field of study, blending the study of plants with anthropology and history. By learning about the many ways people have cultivated and used plants across the world, we not only understand the intertwined history of plants and people but also get new ideas for developing plants in useful ways.

A Missouri entomologist, Charles V. Riley, discovered the amazing mutualistic relationship between yuccas and yucca moths. Only a certain type of moth can fertilize yuccas, which occurs as the female moth deposits eggs into the flower’s ovary. Without the cross-pollination effected by the moth, the yucca flowers generally cannot produce viable seeds. When he studied this remarkable plant-insect relationship in the 1870s, Riley was Missouri’s first official State Entomologist. The eminent St. Louis botanist George Engelmann had noticed that yuccas apparently need some kind of outside agent to accomplish pollination and suggested Riley look into it.

When yuccas are blooming, it’s time to look for yucca moths (Tegeticula spp.). Peek carefully into the yucca/soapweed flowers: the moths will be about the same color as the petals! The moths and their food plants are an amazing example of mutualism: The moth larvae, hatching from eggs laid in the pistil of the yucca flower, will eat some but not all of the yucca’s hundreds of developing seeds. However, the yucca can afford that price because the female moth possesses specialized anatomy and even special behaviors to cross-fertilize the flowers as she deposits her eggs.

Yuccas are in the same family as agaves, and the famous Joshua trees of the American Southwest are species Y. brevifolia. The state flower of New Mexico is the yucca. In the Southwest, many people are learning to landscape their yards using the many native, drought-tolerant species of yuccas and agaves; as with here, native landscaping helps expand habitat for native species. It also demands much less water and maintenance.

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