Glass-Spined Silver Torch
Cleistocactus strausii

Family: Cactaceae

This is a smaller Cleistocactus which only usually gets about 2-3’ tall. Similar to the more common C. strausii, it has clusters of spines, some white (or “glassy”) hairlike spines, and a few yellowish or brown spines. Summer encourages tubular flowers that are reddish, followed by tiny spherical fruits that are light greenish to brick-red.

Plant in full to part sun, low water—maybe once a month in summer, and not at all in winter. Plants are hardy to 20°F. Container plants should be watered once or twice a week in summer, and maybe lightly watered once a month in winter if there is no rain. Make sure nursery-grown plants are acclimated to sun—so often, plants in nurseries are grown in more shade, in greenhouses, and may take some time and work to acclimate.

Flowers are pollinated by hummingbirds. Fruits are eaten by all sorts of birds.

The etymology of the genus name comes from the Greek term “kleistos”, “ which means “closed” and is attributed to the characteristic of its flowers scarcely opening. The species, hyalacanthus, means glass spine, referring to the almost clear-white spines that this plant has. The genus Cleistocactus has about 20 species native to mountainous areas of South America (Peru, Uruguay, Bolivia and Argentina).

Photo of mature plant in Bolivia by Martin Lowry, iNaturalist