Scientific: Opuntia santa-rita
Taxonomic note: Because the scientific name of blue blade cactus has been changed many times in the recent past, there is now much public confusion about what is the current 'correct' scientific name. Other past scientific names or synonyms include but are not limited too: Opuntia santarita, Opuntia santa rita var. violacea, Opuntia chlorotica var. santa-rita, Opuntia gosseliniana subsp. santa-rita, Opuntia violacea var. castetteri, and Opuntia violacea var. santarita.
Common: blue blade, Santa rita prickly pear cactus, dollar cactus, purple prickly pear
Family: Cactaceae
Origin: Texas, New Mexico, and Arizona south into northern Mexico.
Pronounciation: O-PUN-tee-a SAN-ta REE-ta
Hardiness zones:
Sunset 13, 18-24
USDA 9-11
Landscape Use: Stem and flower accent cactus for xeric and desert style landscapes, barrier planting in desert gardens, large patio containers.
Form & Character: Shrubby rounded cactus, rigid, dry, very colorful.
Growth Habit: Evergreen, perennial succulent, moderate growth rate, upright and many branched to 6 feet in height with equal spread.
Foliage/Texture: Stems of Opuntia are jointed into flattened sections called clades, blades or pads which store water. All blue blade clades are orbicular (rounded to circular) to 8-inches long and wide. Blue blade clades are generally glaucous blue with a characteristic purple tinge, but under cold or prolonged drought conditions will have a distinct reddish tinge. Mature clades are leafless and spineless. Instead of spines, all blue blade clade aeroles are whitish brown with very short, but very potentially aggravating glochids. Occasionally a terminal pad will have a few clusters of reddish-brown to pink spines to 2-inches long on aeroles at the upper margins. Emerging juvenile clades during the spring months have many small, transitory cylindrical leaves that each taper to a point (like a bunch of coneheads). The texture of blue blade is coarse.
Flowers & Fruits: Flowers cream to yellow on ends of highest clades; fruits reddish orbs in late summer and fall.
Seasonal Color: Consistently blooms in April to May.
Temperature: Heat tolerant, cold hardy to 25oF.
Light: Full sun to partial shade.
Soil: Tolerant
Watering: Extremely drought tolerant, but an occasional summer soaking will keep pads flush. If water stressed, pads will become reddened.
Pruning: None
Propagation: As with all Opuntia, blue blade cactus easily roots at the basal end of pads, seed (generally unnecessary).
Disease and Pests: Mealy bugs (infrequent problem in outdoor landscapes) is minor.....but cochineal scale is a HUGE problem in outdoor Phoenix landscape gardens. This pesky sucking insect attaches itself onto the clades at frequencies that will astonish you. It looks
like cottony cushion scale and produces a purplish red dye. Cochineal scale on blue blade cactus is way difficult to control. In my yard, I try to "prevent" infestations by reducing stem pad density (removing pads in July) to avoid crowding and allow good air flow, and by periodically spraying off the cactus clades (stem pads) with a garden hose fit with a high pressure nozzle.
Additional comments: Blue blade cactus is one of many good species of shrubby Opuntia for use
in Phoenix, but with one GIANT caveat, the dreaded cochineal scale insect. Since the botanical name of this cactus has changed several times in the last 20 years, don't be surprised at others you may meet who hold fast to calling it by an older scientific name.
Final recommendation: If you're not prepared to take frequent actions to prevent or minimize the damage caused by the pesky cochineal scale insect, then my recommendation is to NOT plant this otherwise wonderful cactus in your yard.
