Yucca schottii Engelmann, in Acad. Sci. St. Louis Trans. (1873) 3:46

Synonyms:
Yucca puberula sensu Torrey in Botany, Emory Report, 221 (1859) in large part, Not Haworth (1828)
Yucca macrocarpa Engelmann in Bot Gaz. 6: 224 (1881)
Yucca macrocarpa Trelease in Rep. Missouri Bot. Gard. 3: 162, t. 46 (1892) as synonym of Yucca schottii Engelmann. Not Yucca macrocarpa (Torr) Merriam (1993)

Un published names:
Yucca schottii var. jaliscensis
Yucca schottii var. madrensis

Type location:
Sierras west of Santa Cruz Co., Arizona

Distribution:
In the mountains of southern Arizona, and adjacent corner of New Mexico, along the southern boundary of Arizona and New Mexico, particularly in New Mexico. In oak woodlands and shady canyons at 1200 to 2400 m elevation.

Short description of the species:
Plant arborescent, with quite symmetrical rosettes of leaves, growing in clumps of stems and rosettes. Stems mostly 2 or 3 but occasionally up to 6 stems, 150 to 460 cm tall and as much as 32 cm thick. Leaves 40 to 90 cm long, 2,5 to 5,5 cm wide. divergently spreading, thin, flexible. Leaf margin thin, without fibers or with few fine fibers. Inflorescence  Scape very short, panicle mainly within the leaves, but somewhat extending above, narrowly ellipsoidal, rather densely branched, very tomensose or rarely glabrous, Flowers small, 2 to 3,5 cm long, subglobose, white. Fruit 6 to 12,5 cm long 2,5 to 3,8 cm thick, constricted near the apex. Seeds 0,5 to 0,8 x 0,7 to 1 cm, thick, flat or rather hemispherical, rough, dull, black, wingless.

Hardiness:
I have not have had much experience with this species, In the summer of 2000 did I plant a 3 year old seedling in one of my protected beds. and one in my unheated greenhouse. Time will tell if they survive there!
According to the book by Mary and Gary Irish; Yucca schottii is hardy at Plants Delight Nursery, Raleigh, North Carolina and at Yucca Do Nursery, Hempstead, Texas, in those places it should be able to handle down to -23C.

Pictures:
 

Yucca schottii northwest of Nogales Arizona. Photo by Craig Howe ©2000	Yucca schottii orthwest of Nogales Arizona.  A very beautiful specimen with many leaves. Photo by Craig Howe ©2000	Yucca schottii. Grown in Alexander Heim's garden in Greece. Copyright 2007 Alexander Heim.

My own plants:

#751 Yucca schottii, Arizona, Southern Santa Rita Mts., AG58, sown 1997 got the seeds from Mesa Garden.
The seedlings of  Yucca schottii are growing very fast, the plant on the picture is only 3 years old, the white label is 2 x 12 cm.
Photo by Benny Moeller Jensen ©2000

Reference:
ENGELMANN, Acad. Sci. St. Louis Trans. (1873) 3:46
ENGELMANN, Bot Gaz. 6: 224 (1881)
IRISH, MARY & GARY; Agaves, Yuccas, and Related Plants: A Gardener's Guide, (2000)
MCKELVEY, Yuccas Southwest. U.S. 1: 82-92, 1938
WEBBER, Agric. Monograph U.S.D.A. 17: (1953)
POWELL, Jerry A., Biological Interrelationships of Moths and Yucca schottii, in University of California publications in entomology vol. 100 (1984).
TORREY, Botany, Emory Report, 221 (1859) in large part, Not Haworth (1828)
TRELEASE, Rep. Missouri Bot. Gard. 3: 162, t. 46 (1873)
TRELEASE, Rep. Missouri Bot. Gard. 4: 185, t. 3 (1893)
TRELEASE, Rep. Missouri Bot. Gard. 33: 98, tt. 55, 2 figs. 85, fig 1, 96, fig 1 (range map) (1902)