Pachycereus schottii f. monstrosus
Synonym: Lophocereus schottii f. monstrosus
Family: Cactaceae​
​Common Name: totem pole cactus
Origin: Pachycereus schottii f. monstrosus inhabits alluvial plains and desert riparian environments, in gravelly soils. While the straight species is native to the deserts of mainland Mexico, Baja California, and the extreme south of Arizona, the monstrosus form is only found northeast of El Arco, the midpoint of Baja California. 
Description: P. schottii f. monstrosus is a slow growing cactus with a columnar stem - usually trunkless - which basally branches in a candelabra formation. The dark-green and waxy stems reach up to 15 feet in height, possessing 5-9 irregularly-shaped ribs, and unusual, knobby, tubercle-like swellings along the trunk. Unlike the straight species, areoles are few and insignificant, very rarely developing pink flowers.
  • Interesting Features:
    • No seeds are produced by P. schottii f. monstrosus, and it is unknown if the flowers also develop the edible red fruits of the straight species.
    • The totem pole cactus is named for the species’ unusual protuberances, which resemble multiple faces carved along the trunk.
    • Rarely, the stems will spiral left or right, developing an unusual form that is highly prized by collectors.
  • Uses: Aside from its value in cultivation, no ethnobotanical qualities specific to P. schottii f. monstrosus are known.
    • However, the bark of the straight species, P. schottii, has been used to treat cancer, diabetes, ulcers, sores, stomach disorders, and tuberculosis.

Cultivation and Care:
  • Watering: Low
    • When grown in large aggregations, the totem pole cactus is extremely drought tolerant.
    • Solitary specimens require more frequent irrigation – up to once every 2-3 weeks in summer. Younger and smaller species must be watered more often.
  • Soil: This species should be planted in a porous, rich, sandy or gravelly soil with a pH between 6.1-7.8.
    • To prevent root-rot, ensure that cactus-soil is well-draining, and add perlite or coarse sand if needed.
    • Replenish with fresh substrate every few years, to encourage growth.
  • Lighting: Provide as much full sun and direct light as possible in order for species to thrive. It may be necessary to use a grow-light for indoor specimens, as the totem pole cactus will suffer under even partial shade.
  • Propagation: Because P. schottii f. monstrosus only produces sterile flowers, if at all, the only method of propagation is through woody or softwood stem cuttings.
    • Take cuttings in spring or summer, allow to fully callous before planting, and root at a minimum temperature of 68°F.
  • Cold Tolerance: 20°F, USDA hardiness zones 9a to 10a.
  • Special Accommodations: Organic mulches or soil coverings that retain moisture should be avoided, to prevent root rot.
    • Additionally, this species is less frost tolerant than the straight species, and should be covered or taken indoors during the colder months.

Sources:
  1. Llifle Encyclopedia of Cacti
  2. Gardenista
  3. Plant Care Today
  4. World of Succulents
  5. U.S. National Library of Medicine
  6. Succulent Plant Care
  7. Dave’s Garden