Espostoa (2011)

By Eric Driskill (April 2011)

The genus Espostoa was described in 1920 by Nathaniel Britton and Joseph Rose. The name honors the Peruvian botanist Nicolas E. Esposto. The genus consists of up to 16 species. Plants are shrubby or treelike, columnar, branching mainly at the base, many-ribbed and very spiny. They range from Ecuador to Peru.

Espostoas are well known for their lateral cephalia with bell-shaped, tubular flowers which open at night. Cephalia only develop on sexually mature stems near the tops of the stems. Cephalia also typically grow on one side of the stem running parallel down the stem. Flowers are typically 1 to 2 inches in diameter and mostly white with just a few red.

Most espostoas are covered in a dense layer of spines that resemble white hair. Sharp spines await anyone deceived by the white “hair” who feel the need to touch the plants.

Many plants are popular in cultivation due to the color of the hair and spines. Large nurseries often sell small plants in pots almost as a cacti novelty item with catchy common names. These plants aren’t particularly difficult to grow and can turn into nice plants in cultivation, though rarely if ever do they reach the size of plants in habitat.

If pot-bound, the plants’ growth slows down rapidly, postponing any chance of reaching maturity and the development of cephalia. Being columnar and rarely branching in pot culture, espostoas typically don’t take up a lot of horizontal space on the bench. Extreme heat or cold should be avoided, and plants should be grown in well-drained soil mixture. Care should be taken not to overwater your plants.