Astrophytum myriostigma

Bishop's Cap

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Taxonomy

Common Names

Bishop's CapBishop's Miter

Context

nativeRegion

Chihuahuan Desert, northeastern and central Mexico.

usdaZones

9b–11b (can be grown indoors in cooler climates).

companionPlants

Echinocactus, Mammillaria, Ferocactus

culturalUses

Primarily ornamental; valued in cactus and succulent collections for its distinctive form and minimal care needs.

Care

LightBright, direct sunlight for several hours per day. Can tolerate some partial shade but grows best with abundant light.

WateringWater sparingly; allow soil to fully dry between waterings. Reduce watering in winter dormancy.

SoilWell-draining cactus mix with added grit or pumice to prevent root rot.

FertilizerDilute cactus fertilizer during the active growing season (spring-summer), once a month.

HumidityPrefers low humidity; avoid excessive moisture in the air and soil.

TemperatureIdeal between 20–30°C (68–86°F); minimum temperature 5°C (41°F). Protect from frost.

HabitSlow-growing, spineless cactus with ribbed, star-shaped stem.

Mature Size10–20 cm (4–8 inches) tall and wide under cultivation.

Growth RateVery slow-growing.

BloomingYellow flowers appear at the apex in spring or summer, typically on mature plants.

DormancyDormant in winter; withhold water during this period.

MethodsSeed (most common), Occasional offset division (rare)

DifficultyModerate; seeds require patience and careful handling.

Best SeasonSpring to early summer for sowing seeds.

PruningNone required; simply remove any dead or rotting tissue.

RepottingEvery 2–3 years, preferably in spring, to refresh soil and support root growth.

Pests & DiseasesSusceptible to mealybugs and root rot if overwatered.

ToxicityNon-toxic to humans and pets.