This columnar plant becomes 10 to 20 feet tall if grown outdoors, and since it's a bit harder than most night-blooming cereus plants), more gardeners have an opportunity to grow it outdoors. It needs less water and more sun than Epiphyllum. San Pedro cactus is multi-stemmed and fast-growing. Like the better-known peyote, it is hallucinogenic.
 
Size guide:
Mini - 6cm 
Small - 8cm 
Medium - 10cm
Large - 13cm
Extra Large - 15 cm