February 2025 Mini Show

Rebutia by Tom Glavich

The genus Rebutia has grown to swallow Sulcorebutia and Weingartia. There is no reliable distinguishing characteristic that separates what once were three genera.

Rebutia, Sulcorebutia and Weingartia were genera from the highlands of Bolivia and Northern Argentina. They are similar in appearance, in habitat and culture. Coming from high altitudes, they are tolerant of cold, and if dry, can be left out in all weather. The populations of all three overlap.

There has been debate almost from initial discovery whether or not Weingartia, Sulcorebutia and Rebutia belong in the same genus. All three genera grow over large altitude ranges, and many species are so variable that collections from nearby populations or even the same population at different times have been given different names. There are far more names than species. The books by John Pilbeam help make sense of the species and varieties, and the New Cactus Lexicon gives the names under which the older species can now be found. Many names have changed multiple times over the years.

Rebutia are easily grown. They are dormant in winter, and start to grow in late March or April. They flower from April through June, with the peak flowering period varying from year to year depending on the weather. Two flowering cycles are common in cultivation in California. The flowers appear in abundance, and vary in color from purple and red through orange to yellow. They do well in normal cactus potting mixes, and grow best with steady fertilization when in active growth. They are attractive to spider mites. Damage can be prevented by frequent inspection, and a weekly, forceful wash down with water.

Many plants eventually get a woody brown growth at the base of the plants, which creeps upward. This is known as creeping crud and is a fungal disease. It can be avoided by maintaining the plants in active growth. Better yet, small offsets should be periodically used to start new growth. When the creeping crud appears, the plant should be discarded. It just gets uglier as time goes by, and the presence of diseased plants makes it easier for the fungus to grow and spread.

Propagation from offsets is easy. The offsets should be cut off, left to dry for a few days, and then replanted. Very small offsets can be successfully rooted. Seed is easy to germinate but is short-lived.

Notable Species

Rebutia heliosa is an orange flowered form. It clumps rapidly in cultivation with a dark green body, small brown areoles and short whitish spines in a spiral pattern.Rebutia steinmanni ‘christinae’, also found as R. christinae is from Salta Argentina, and is one of 7 species included in R. steinmanni. It has dense off white spines and wonderful red flowers with a yellow center. Rebutia marsoneri from Jujuy, Argentina is noted for its spectacular golden yellow flowers.

Rebutia pygmaea comes in at least 20 varieties, many of which were originally described as species. Flower color varies over the full range for the genus. It’s a challenge to keep some of the varieties small. Easy to grow.

Rebutia (Sulcorebutia) rauschii is known in several forms. The most common is a dark purple bodied form. Second most common is a green bodied form, and the third is a golden spined form. Other forms are also available, but rarely seen. All are slow and beautiful, and harder than most others to keep looking good. All are worth the effort.

Rebutia neocumingii (Weingartia longigibba) is variable, with many great forms.

Rosettes

Rosettes smaller than 10″ diameter refers to the plant rosette growing to no more than 10 inches across.  The idea here is to look at the diminutive forms of these wonderful  succulent (non-cacti) genus.  Some examples may include rosettes of Aloe, Gasteria, or Haworthia.