Scientific: Opuntia orbiculata (Synonym: Opuntia dillei)
Common: western prickly pear
Family: Cactaceae
Origin: North America ranging from Oklahoma, Texas, New Mexico, Arizona, the desert mountains of Nevada and California, into northern Mexico.
Pronounciation: O-POON-tee-a or-bic-u-LA-ta
Hardiness zones:
Sunset 8-9, 12-24
USDA 8-11
Landscape Use: Accent, rock gardens, xeric or desert landscape design themes, water conservation gardens.
Form & Character: Upright, somewhat prostrate, spreading, rugged, intimidating, arid, tough, dangerous, highly variable.
Growth Habit: Evergreen, succulent, herbaceous perennial, sparsely branched, moderate growth rate to 3 feet tall, moderately spreading to 6-feet wide.
Foliage/Texture: Generally leafless, segmented stem clades or cladodes (lay people call them "pads" or "blades") are variable in shape ranging from orbicular, spatulate, oval, obovate, or obdeltoid, clades glaucous green to blue, aeroles contain brownish glochids, often one to several white to yellow spines per aerole that sometimes orient in a downward direction, spines mostly straight, sometimes curved; very coarse texture.
Flowers & Fruits: Flowers are yellow to orange with green stigmas; fruits are egg-shaped, barrel-shaped, or subglobose, umbilicate, reddish-purple, to 2-inches long, purple when mature.
Seasonal Color: Yellow flowers in later spring.
Temperature: Fully hardy in Phoenix.
Light: Full sun, but will tolerant light, filtered partial shade, no full shade.
Soil: Tolerant, but prefers well-drained soils.
Watering: Only occasional supplemental irrigation is needed during the summer to western prickly pear clades looking landscape 'plump'. Otherwise, no supplemental water is needed.
Pruning: None
Propagation: Asexual propagation by removal on single or multiple clades is easy.
Disease and Pests: None, except root rot if soils are overly irrigated and poorly drained.
Additional comments: Though exceptionally easy to culture in Phoenix xeric landscapes and highly environmentally tolerant of the Phoenix climate, western prickly pear is generally considered a less desirable, 'run-of-the-mill', prostrate and spreading cactus for landscape use because there are other Opuntia species with more ornamental qualities.
Taxonomic confusion: Opuntia orbiculata is somtimes misidentified as Opuntia engelmannii.
