There are over 100 species of Cleistocactus, mostly from Peru, Bolivia, Argentina, Paraguay, and Uruguay. The cactus in the photo is C. strausii, or Silver Torch Cactus. I got this cactus when it was about four inches tall. Once it reached one foot, I planted it in my garden in the dappled shade of a Palo Verde tree, and it has now grown to two feet. This columnar cactus can grow to eight feet tall.
C. strausii starts blooming when the column reaches 18 inches. This cactus bloomed last year for the first time when it was 19 inches tall. This year, the flowers are about two months early.