Of the many white-spined cacti available in cultivation, Cleistocactus strausii is one of the best for southern Arizona. Known as silver torch or wooly torch cactus, this native of montane Bolivia and Argentina is well adapted to both the heat and cold of our desert valleys. Several to many columnar stems arise from the ground and can grow to about eight feet tall. The dense bristly white spines nearly completely conceal the stems. The narrowly tubular, deep red flowers are borne freely near the tops of the stems from February into May in our climate, and are visited by hummingbirds.
This species is large and vigorous enough to be used as a landscape subject, either in the ground or large pots. Light afternoon shade is best in the desert. Hardy to at least 20 F, and even lower when sheltered by a tree or other overhang. They appreciate regular irrigation in summer, and should be kept dry in winter to prevent root rot.