Rebutia minuscula
Synonym: Rebutia krainziana
Family: Cactaceae​
​Common Name: Krainz’ crown cactus
Origin: The specific origin of this cactus is unknown, but it was likely developed through horticulture in the Jujuy Province of Argentina.
Description: The Krainz’ crown cactus is a dark green spherical cactus with white areoles and miniature spines. It begins to offset after 2-3 years, developing a tight clumping bundle of stems. In spring, R. minuscula will flower, developing large reddish to orange flowers, with certain varieties capable of producing yellow, violet, or white.
  • Interesting Features:
    • Although usually called Rebutia krainziana or Rebutia marsoneri, the often unused accepted name for this species is Rebutia minuscula.
    • The only factor discerning the accepted species R. minuscula from R. marsoneri is the latter developing yellow flowers, while R. minuscula usually remains in the red to orange range.
  • Uses: All naturally occurring variants of Rebutia minuscula have been used in cultivation as houseplants or in xeriscape gardens.

Cultivation and Care:
  • Watering: Low
    • Provide regular irrigation in summer, allowing soil to completely dry between waterings, and stop watering in autumn.
  • Soil: Cultivate in a very open mineral soil of 50% pumice grit or sand, with a pH slightly below 7.
  • Lighting: R. minuscula fares well as both an outdoor or container plant, provided a sunny window is available, as full sun to bright shade is required to maintain strong, dense spines.
  • Propagation: Rebutia minuscula can be propagated from offsets and seed. Stratify the seed and plant indoors during spring to summer, keeping ventilated and avoiding direct sunlight. Do not disturb seedlings until they are well rooted, and then transfer to separate pots.
  • Cold Tolerance: 20°F, USDA hardiness zones 9b to 11.
  • Special Accommodations: Due to the quick growth of this species, R. minuscula should be repotted every two to three years, preferably at the end of winter. Do not water for a few weeks after repotting, to protect broken roots from root rot. Additionally, protect from stem rot and red spider mites, to which the Krainz’ crown cactus is susceptible.

Sources:
  1. Cactus Art Nursery
  2. Plant Desert
  3. World of Succulents
  4. Llifle Encyclopedia of Succulents
  5. Gardeners' World
  6. Plant Lust
  7. Cactus Limon
  8. Dave's Garden