– Sulcorebutia tiraquensis (2019)

By Bob Williams and Marge Williams (January 2019)

The October 2018 meeting program by Dave Janas was a real treat. His talk on the cactus of Bolivia and perspectives on the country were very informative. It is amazing that in this day and age, there are places in the world where large areas have not been explored. Unfortunately, due to extreme poverty and exploitation, many of these areas are threatened.

The main attendance prize at the meeting was a specimen Sulcorebutia tiraquensis var. bicolorispina. The plant and Janas’ presentation went hand in hand. We did not find much in our “exploration” for information about this plant.

Sulcorebutia tiraquensis var. bicolorispina grows north and east of Cochabamba in southern Bolivia. Cochabamba is a city with a population of 625,000. It is in a valley surrounded by the Andes Mountains. Even though it is in a valley, the elevation is 8,200 feet. However, it is known as the “City of Eternal Spring” or “The Garden City” because of its springlike temperatures all year round. The average high temperature is in the mid-70s all year. From May through August, the average lows are in the mid-30s. For the other eight months, the lows are in the mid-40s to low 50s.

An extended dry season runs from May until October, with a wet season that generally begins in November. The principal rains end in March. During the rainy season, 12 inches of rainfall is average. During the seven-month dry season, only 2 to 3 inches of rain fall. This information is important to understand the conditions this plant grows under and how to care for it.

As stated, Sulcorebutia tiraquensis var. bicolorispina is found in southern Bolivia. It grows mainly on dry, flat, rocky areas. This means a well-draining soil mix is a must. This plant is a localized form of S. steinbachii. There are more than 20 different forms or varieties of this plant. Due to location, flower color, body shape or spine length may be slightly different.

In both habitat and cultivation, the plant will readily clump. The clumps can form from the base, and as the plant grows taller, clumps form on the body. In our research, we could not find any information on how large the clumps get. We also found no information on how tall the plant will grow. For reference, the plant we got is about 6 inches in diameter and 5 inches tall. There are over 20 heads growing from the main plant body, but we don’t know the plant’s age.

This sulcorebutia can be completely concealed by fine, silvery-white and dark-red or mahogany-colored spines. They help protect the plants from cold temperatures in the winter and conserve water during the dry season. This plant can survive cold temperatures down to -5 degrees F. This may make the sulcorebutia a candidate for a winter-hardy garden. Just remember that in habitat, this plant gets almost zero precipitation in the winter, so it needs to be in a dry area in your garden or be protected from moisture.

The characteristic that makes this plant and other Sulcorebutia species stand out is the flowers. Sulcorebutia tiraquensis var. bicolorispina will produce large numbers of flowers around the base. The pink to light purple flowers are 1 to 1.75 inches long and 1.5 to 2 inches wide, and last up to five days. To get the plant to produce large numbers of flowers, it must be kept in a cool place where temperatures are in the mid-30s to low 40s in the winter.

The plant is fairly easy to grow. As with many succulents, fast-draining soil mix is a must. It can take moderate watering in the summer. In winter, you should not water much, if at all. The plant can tolerate full sun, but in our climate, filtered sun may be best during the hottest part of the day to avoid sunburn. Remember, they do not get many 90- to 100-degree days in habitat. You can propagate this plant by seed or planting offsets.

One of the most enjoyable parts about researching an article is coming across new websites. Sulco-Passion (https://english.sulcopassion.be) is a hidden gem. We did not use material from the site for this article, but it has a wealth of information on Weingartia, Sulcorebutia and Cintia. There is also a “Sulcorebutia Passion” Facebook page. If you are interested in these plants, check it out.

Source:

Llifle Encylopedia of Succulents – http://llifle.com/Encyclopedia/CACTI/Family/Cac taceae/12098/Sulcorebutia_tiraquensis_var._bic olorispina