WikiBotanicals:Yucca

Yucca  is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae.

Background
The stiff, broad, sword-shaped leaves of Yucca filamentosa are familiar to all. In midsummer the flower stalks, rising to a height of 6 feet, are also familiar. The flowers are white and pendulous. It is the personal opinion of the writer that, except when in bloom, they are stiff, coarse and undeserving of a place in a small garden. It must be admitted, however, that they are remarkably drought-resistant, and will thrive where trees rob the soil so that more dainty plants cannot exist. This species is wild from South Carolina to Florida.

Culture
They will exist for a generation and transplant with difficulty when the plants become old as the roots go deeply.

Propagation
Seedlings will bloom when four to five years old. As the plants sucker freely, this furnishes a ready means of propagation.

Uses
When used at all they are best planted as specimens or among shrubbery. They are especially good in sandy loam and well drained soil.

Species
Y. baccata, though not adapted to the colder regions, grows freely as a native in southern Colorado to New Mexico and Nevada. The leaves are thick. The flower stalks are only 3 feet tall and the flowers are large, 3 inches long.

Y. brevifolia, the Joshua-tree, is commonly seen throughout the semi-arid regions of California. These plants grow 30 feet tall but with leaves less than 10 inches long.

Y. filamentosa

Y. flaccida has leaves which are less rigid and curving, the threads are straighter and it is hardier than Y. filamentosa.

Y. glauca (Soapweed, Beargrass) bears an underground trunk from which clumps arise. The leaves are narrow, stiff, gray-green with a white margin. The flowers are white or purple-tinted. Soap is made from the roots.

Y. harrimaniae, a native of Utah, Colorado and New Mexico, is the smallest of the Yuccas, producing tufts 4 to 8 inches in diameter with needlelike leaves edged with white filaments. It succeeds in all soils, from adobe to sand.

Y. schidigera (Mojave yucca, Spanish Dagger) Mojave Desert and Sonoran Desert of southeastern California, Baja California, southern Nevada and western Arizona. This yucca typically grows on rocky desert slopes and Creosote desert flats between 300–1,200 metres (980–3,900 ft) altitude, rarely up to 2,500 metres (8,200 ft). They thrive in full sun and in soil with excellent drainage. It also needs no summer water. It is related to the Banana yucca (Yucca baccata), which occurs in the same general area; hybrids between the two are sometimes found.

Y. utahensis