Cleistocactus (2018)

By Rey Gonzalez (February 2018)

Cleistocactus is a columnar member of the Cactaceae family described by Curt Backeberg in 1913. It is native to the mountainous areas of Peru, Uruguay, Bolivia and Argentina, and can be found growing in large, shrubby clumps mixed in with other vegetation or clambering over boulders. The name Cleistocactus comes from the Greek “kleistos,” meaning “closed cactus,” a reference to the appearance of the flowers.

Some might say that Cleistocactus is a genus of quantity over quality, because many of the features of this genus are small, but profuse. The stems are typically from 1 to 2.5 inches or so in diameter, but branch readily at the base to form noticeable clumps. In general, the spines are likewise small and flexible, but in most cases, are very numerous – even to the point of obscuring the stems.

Many species have flowers that resemble little tubes of lipstick or firecrackers. The tubular, rose-red flowers are about 3.2 inches long and are scattered along the stems.

Several species are extremely popular in cultivation and are among the most common cacti in nurseries worldwide. The two most popular of all are Cleistocactus strausii and C. winteri. Species like C. strausii can reach a height of over 10 feet, while C. winteri and others are branching cacti with spreading, arching, pendant or trailing stems that grow up to 40 inches long and 1 inch wide.

To grow Cleistocactus plants, choose a location that gets full sun and has well-draining soil. Water them during spring and summer, when the top inch of soil dries out. During the fall, reduce watering to every four to five weeks if the ground dries out.

In winter, keep the soil dry to prevent root rot. Cool temperatures combined with moist soil and dormancy can cause the roots to rot. A slow-release fertilizer applied in the spring will be sufficient for the whole year.

It is possible to propagate by cutting a small branch from a cleistocactus and rooting it, but this inevitably leaves a disfiguring scar near the base of the main stem. If an offset is removed to be used in propagation, remember to dry it for a week or so, letting the wound heal. Rooting usually occurs within three to eight weeks. All Cleistocactus species can be susceptible to mealy bugs and spider mites.

Sources:
Rikke’s Plants: Cleistocactus strausii – http://www.bihrmann.com/rikke/subs/cle-str-sub.asp
Ecology & Evolutionary Biology Conservatory – https://web.archive.org/web/20051101024213/http:/florawww.eeb.uconn.edu/acc_num/198502128.html
World of Succulents: Cleistocactus winteri – Golden Rat Tail – https://worldofsucculents.com/?scientific-names=cleistocactus-winteri