Scientific: Cereus repandus (Synonyms: Cereus peruvianus, Lophocereus schottii)
Common: hedge cactus, Peruvian apple, queen of the night, night blooming cereus (the common names for plants in the genus Cereus are all mixed up!)
Family: Cactaceae
Origin: Brazil, Paraguay, Uruguay and Argentina (uncertain)
Pronounciation: Ser-E-us re-PAN-dus
Hardiness zones:
Sunset 13, 16-17, 21-24
USDA 9 (marginal, protect from cold)-11
Landscape Use: Strong focal point for xeric landscape themes, container plant, rock garden, large patios, and even as a natural screen for garbage containers.
Form & Character: A majestic columnar cactus, upright, tree-like, branched and contorted, convoluted, dominant, arid.
Growth Habit: Succulent perennial, slowly upright and branched to 20 feet (specific variants can grow to 50 feet).
Foliage/Texture: Stems sometimes segmented, dull to light green, ribs mostly 12, mostly spineless to very short spines; coarse texture.
Flowers & Fruits: Numerous nocturnal flowers are large to 6-inches across, petals white with dull reddish sepals, somewhat fragrant, stigma often exerted before petals open, flowers borne on an elongated stalk, occassionally short and ridged; fruits, globose, red when ripe and rounded like a "small apple" (thus the plant's common name) with a white pulp to 2.5 inches in diameter.
Seasonal Color: Spectacular flower display in late spring (typically May in Phoenix). Also, sometimes will flower again during late summer or early fall at the end of the summer monsoon season.
Temperature: Tolerant to 20oF.
Light: Full sun and NO shade.
Soil: A well-drained mineral soil is best.
Watering: Water only occasionally if at all during summers.
Pruning: None, except to control size by occasionally thinning out awkward or crossing stem branches.
Propagation: Easily propagated from softwood stem cuttings of most any length. Will develop roots after directly planting stem cuttings into the soil (right side up!). Make sure to first allow the cut surfaces of the stems to harden for several weeks
(callous over) before planting directly into soil.
Disease and Pests: Susceptible to root rot in damp poorly drained soils.
Additional comments: With age, this arborescent cactus will become very large and will occupy significant physical and visual space in the landscape. The large fruits of this cactus are presently being researched as a significant fruit crop for production in arid climates like Israel.
More taxonomic tidbits: 'Cereus' is a latin word meaning 'wax' or 'torch'. Cereus repandus is very similar in appearance and is sometimes confused with Cereus hildmannianus. Are they the same or different? The stem morphology of these two upright columnar cacti is similar, except Cereus repandus lacks the distinct glaucous blue stem segments (especially younger stem segments) that characterizes Cereus hildmannianus.
'Monstrose' or 'Monstrosus' are botanical terms used to describe a naturally-occuring mutant growth formation that resembles a contorted, club-like shape in cylindrical or columnar cacti and a wavy body shape in cacti that have flattened cladodes or pads. Cereus repandus forma Monstrosus is often confused with Cereus hildmannianus forma Montrosus; the former has contorted stems that are generally dull grayish green in color, while the later has stems are strikingly glaucous blue stems. Here's an incredibly cool image of a severely fasciated Cereus repandus specimen!