Scientific: Yucca thompsoniana (synonym: Yucca rostrata var. linearis)
Common: beaked yucca, Thompson yucca
Family: Asparagaceae (subfamily Agavoideae)
Origin: Southwest Texas near the Rio Grande river near and within Big Bend National Park into Chihuahua, Mexico.
Pronounciation: YUK-ka thomp-son-ee-A-na
Hardiness zones
Sunset 5-24
USDA 6-11
Landscape Use: Specimen accent, Spanish architecture
Form & Character: Upright, stiff, alarming and dangerous, stately, dominant, arborescent with age, stately.
Growth Habit: Evergreen, fibrous, perennial monocot large shrub to small tree, often many branches and upright to 10- to 15-feet tall with up to an equal spread.
Foliage/Texture: Relatively stiff and dagger like glaucous leaves with finely serrate and yellowed margins (up to 24 inches in length) tapering to a sharp tip; medium texture.
Flowers & Fruits: Multiple, extended slender panicles of creamy white-colored, bell-shaped flowers, stalks to 5-feet tall. Fruits are a non-ornamental capsule, seeds are a dull black.
Seasonal Color: Creamy white flowers during late spring.
Temperature: Tolerant of Phoenix heat. Also, VERY cold tolerant to -10oF.
Light: Full sun in Phoenix.
Soil: Tolerant, grows best in alkaline soil.
Watering: Very drought tolerant, but looks better with occassional summer irrigation.
Pruning: Remove spent flower and fruiting stalks only. Electively leave the dead leaves on for authenticity as they can create a very tight skirt.
Propagation: Seed (soak seed in tepid water for 24 hours before sowing to shorten germination period), offsets, and root cuttings
Disease and pests: None
Additional comments: Yucca thompsoniana looks like a smaller hybridized version of Yucca brevifolia and Yucca rostrata. There is a very boss-looking dwarf phenotype that grows only on the Edwards Plateau of Texas. Beaked yucca is found over a wide range of landscape across the United States from Brooklyn, New York to Tarzana, California. It grows exceptionally well in Phoenix and Tucson, Arizona.
Taxonomic footnote: Some confusion exists among yucca enthusiasts between what is Yucca thompsoniana verses Yucca rigida.