PLNTversePLNTverse
Plants › Cacti

sanddollar (Astrophytum asterias)

Astrophytum asterias is a small, solitary, spineless cactus with a flattened globular to disc-like form. It is perennial.

LightAstrophytum asterias takes full sun, and cultivation information indicates that ample sunlight helps maintain flowering.
WaterIt has low water needs; allow the growing medium to dry between waterings, provide somewhat more water during summer growth, keep it very dry in winter, and avoid waterlogging to reduce the risk of root rot.
HumidityIt is generally reported to prefer low humidity.
TemperatureBased on few sources, a cold minimum of about -6 °C is reported. It is generally reported to tolerate brief light frost and to be frost hardy. It rests cool and dry in winter.
Track your sanddollar in the PLNTverse app
sanddollar illustration

Overview

Astrophytum asterias is a small, solitary, spineless cactus with a flattened globular to disc-like form. It is perennial.

Origin and habitat

Sources differ on its native range, describing southern Texas and the lower Rio Grande Valley in the United States and Tamaulipas and Nuevo León in northeastern Mexico; its surviving wild distribution is more restricted than in the past. It grows in dry thorn scrub, grassland, and rocky or gravelly places, including hills, depressions, and beside dry riverbeds, on substrates ranging from gravelly alluvial loam to saline or calcareous clay; plants often sit close to or partly buried in the ground and may occur in shade from other plants or rocks. It is reported from warm-temperate to subtropical, semi-desert and grassland-type dry climates with low annual rainfall and low elevations.

Characteristics

Sources differ, but mature plants are reported to be about 2.5–6 cm tall and about 5–15 cm across. It is reported to grow slowly and take a long time to mature. Flowers are borne at the top of the plant and are yellow with red at the base or throat, with conspicuous wool on the outside; flowering occurs from late spring into summer. Sources differ in descriptions of the fruit, which is described as oval, green to pink, and covered with soft hairs.

Light

Astrophytum asterias takes full sun, and cultivation information indicates that ample sunlight helps maintain flowering.

Watering

It has low water needs; allow the growing medium to dry between waterings, provide somewhat more water during summer growth, keep it very dry in winter, and avoid waterlogging to reduce the risk of root rot.

Humidity and airflow

It is generally reported to prefer low humidity.

Temperature and dormancy

Based on few sources, a cold minimum of about -6 °C is reported. It is generally reported to tolerate brief light frost and to be frost hardy. It rests cool and dry in winter.

Growing medium and mounting

It needs a porous, fast-draining mix; sources differ on substrate preference, with species-level horticultural information favoring an alkaline, porous soil while genus-level information recommends well-drained acidic sandy soil or a cactus and succulent mix.

Feeding

It is reported that diluted liquid fertilizer may be applied after flower buds form.

Propagation

Propagation is mainly by seed, which can germinate quickly, while some cultivated forms are propagated by grafting.

Common problems

Overwatering, waterlogging, and persistently wet growing medium can lead to root rot and are major cultivation problems, with persistent moisture particularly avoided in winter. It prefers dry to semi-arid conditions, can tolerate brief cold, and requires dry winter management.

Identification

The plant is flattened and spineless, with gray-green to greenish-brown skin that may bear spots of white hair-like scales, low ribs typically arranged in a star-like pattern, and large woolly areoles.

Photos

Astrophytum asterias
📷 GaleoC · CC BY-SA 3.0 · source
Astrophytum asterias
📷 Devon Bradley, some rights reserved (CC BY), uploaded by Dev · CC BY · source

Sources