Ariocarpus retusus (Star Rock)

Scientific Name

Ariocarpus retusus Scheidw.

Common Names

Star Rock, Living Rock, False Peyote

Synonyms

Anhalonium elongatum, Anhalonium furfuraceum, Anhalonium prismaticum, Anhalonium retusum, Ariocarpus confusus, Ariocarpus elongatus, Ariocarpus furfuraceus, Mammillaria furfuracea

Scientific Classification

Family: Cactaceae
Subfamily: Cactoideae
Tribe: Cacteae
Genus: Ariocarpus

Description

Ariocarpus retusus is one of the largest and fastest-growing species of the genus Ariocarpus, known for its slow growth. The stem is grey or blue-green, flattened globose, up to 5 inches (12.5 cm) tall, and up to 10 inches (25 cm) in diameter. Despite its slow growth, often taking ten years to reach flowering age, it is a desirable cactus for cultivation, having attractive flowers and an interesting form. The flowers are white to pink, occasionally with reddish midribs and up to 2 inches (5 cm) in diameter.

Ariocarpus retusus (Star Rock) — *Photo via misplant.net*

Hardiness

USDA hardiness zones 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).

How to Grow and Care

You should plant your Ariocarpus in soil specifically formulated for cacti. You can buy a cactus mix at your local nursery. Do not use generic soil mixes because they will not provide enough aeration and drainage. Additionally, using a container without a hole, whether it is a pot or a terrarium, is a bad idea for the same reason.

Ariocarpus need a lot of sunlight. However, in hot, dry areas, they can be damaged by excessive sunlight, so you should either use a shade-cloth to limit their sun or move them out of the sun during the hottest hours of the day. In more temperate areas, direct sunlight is fine.

These cacti prefer to be kept at room temperature or slightly lower and in low humidity.

Water your Ariocarpus when it is dry, but then wait until the soil dries out completely to water it again. See more at How to Grow and Care for Ariocarpus.

Origin

Ariocarpus retusus is found mainly in Mexico.