Echinopsis terscheckii
Synonym: Trichocereus terscheckii
Family: Cactaceae​
​Common Name: Argentine saguaro
Origin: Echinopsis terscheckii is widespread throughout Argentina, including the Catamarca, Salta, Jujuy, La Rioja, San Juan and Tucumán provinces, as well as Bolivia (Tarija). It is native to grasslands, shrublands, and semiarid Chaco forests, 800 – 2,000 meters in elevation.
Description: E. terscheckii is a large, tree-like cactus with a columnar central trunk, from which numerous arms will develop over time. Stems are woody and possess 8 to 14 (or occasionally, 18) ribs, and brown, felt-like areoles. From older areoles, golden-brown spines will form, giving the cacti a distinctive sunny appearance. Throughout the year, but primarily in rainy summers, very large white flowers develop laterally across the cacti stem. Flowers are showy, beautiful, and bat pollinated – opening after dark and closing the next afternoon. They will be followed by greenish-blue, oblong fruits, with dark seeds.
  • Interesting Features:
    • The Argentine saguaro is often confused with Echinopsis pasacana, a similar cactus of the same region.
    • However, E. terscheckii can be distinguished by its larger size, greater number of branches, fewer ribs, larger flowers, and distinctive golden spines – which become more colorful as the species matures.
  • Uses: E. terscheckii fruits are edible, but are considered inferior to those of E. pasacana.
    • However, cactus branches are valued as fodder for livestock, especially goats, and can be fashioned into rustic furniture and jewelry.
    • E. terscheckii is also harvested for timber, despite the low quality of wood. This has led to classification of wild populations as “vulnerable” by the IUCN red list.
    • Lastly, E. terscheckii possesses hallucinogenic properties, and is comparable to Lophophora williamsii (peyote) and T. pachanoi (San Pedro).

Cultivation and Care:
  • Watering: Moderate
    • E. terscheckii requires regular watering in order to establish, and will shrink when requiring irrigation.
    • However, once mature, allow the soil to fully dry in between waterings, and keep dry in winter.
  • Soil: Provide coarse, well-draining soil with a pH between 6.1 – 7.8. If the species is not left in standing water, nearly all substrates are tolerated.
  • Lighting: Young cacti should be given light shade, but mature plants require strong light and full sun, especially when grown indoors. Bright light will result in bronzing, encouraging spine production.
  • Propagation: E. terscheckii can be propagated by seed, or through woody and softwood cuttings taken in spring. Allow the surface of cuttings to fully callous before planting, and germinate seeds at 68°F.
  • Cold Tolerance: 15°F, USDA hardiness zones 8b to 11.
  • Special Accommodations: The Argentine saguaro is a fast growing and large species which will require repotting every other year in order to encourage development.
    • Additionally, this species must be protected from frost, and should be moved indoors during very cold winters.

Sources:​
  1. Llifle Encyclopedia of Cacti
  2. Tucson Cactus and Succulent Society
  3. University of Arizona Campus Arboretum
  4. Evergreen Nursery
  5. Dave’s Garden
  6. IUCN Red List
  7. Botanical Guides