Scientific: Yucca rigida
Common: blue yucca
Family: Asparagaceae (subfamily Agavoideae)
Origin: Higher Chihuahuan Desert of north central Mexico
Pronounciation: YUK-ka ri-GI-da
Hardiness zones
Sunset 8-24
USDA 7-11
Landscape Use: Strong vertical accent, year-around sculptural interest, oasis and xeriscape landscape design themes.
Form & Character: Stiff, stout and upright, arborescent, foreboding, untouchable, tough, blue, arid.
Growth Habit: Evergreen, fibrous, perennial monocot large shrub to small tree, very slow when young, eventually branched and growing to 12- to 15-feet tall.
Foliage/Texture: Foliage is distinctly glaucous (powder blue in color) and slender to about 2-feet long, VERY STIFF strap-like leaves, inflexible, persistent; medium coarse texture.
Flowers & Fruits: Plumes of cream white flowers on elongated stalks that extend 3 to 5 feet above the canopy of leaves.
Seasonal Color: White flowers during spring.
Temperature: Tolerant of cold to 10oF and lower desert heat.
Light: Full sun
Soil: As with other xeric yuccas, well-drained soil is a must requirement and rocky porous soil is preferred.
Watering: Rarely apply supplemental water.
Pruning: None required, though fastidious horticulturists and 'Hort clods' will feel compelled to 'skin the sidewalls' by pruning off senescent leaves close to the trunk. Others with a penchant for nature or who are just plain lazy will leave the persistent dead leaves intact for that 'natural appearance'.
Propagation: Seed
Disease and Pests: Fungal root rot in damp soils, and desert grubs or larvae that feed on roots. Apply diazinon granules into the soil to control grub activity.
Additional comments: Blue yucca has a very foreboding, stiff and dangerous character that makes use of this plant best limited to areas away from pedestrian traffic areas and activities. Blue yucca is quite similar in appearance to Yucca rostrata, except its foliage is stiff and erect, whereas the foliage of Yucca rostrata is comparatively limber.
