Needs at least 6 hours of direct sun (right in the window where sun actually hits the leaves. A strong grow light 4-6 inches away can substitute) daily. A south-facing window is ideal indoors. It handles more direct sun (right in the window where sun actually hits the leaves. A strong grow light 4-6 inches away can substitute) than most Astrophytums due to its natural canyon habitat.Light

water sparingly (water small amounts, less often. Let the soil dry out almost completely between waterings), allowing soil to dry out completely between waterings. Reduce to near zero in winter dormancy. Overwatering is the most common cause of failure.Water

Keep humidity low. Good air circulation prevents the fungal rot that high humidity (60-80%. Group your plants together, set them on a pebble tray with water, or run a humidifier nearby) encourages.Humidity

Prefers warm summers above 70°F and a cool dry winter rest. Hardy in USDA zones 9b-10 outdoors.Temperature

moderateDifficulty

the bishop's cap or monk's hood cactus

Astrophytum ornatum

Moderate

The Monk's Hood Cactus is the largest and arguably the most dramatic of the Astrophytum genus, eventually growing into a tall column up to 6 feet in the wild, adorned with eight spiraling ribs, bold spines, and diagonal bands of white woolly scales. It starts as a globe in youth and gets more columnar and architectural as it ages, eventually producing large, bright yellow flowers at the crown when it matures. Compared to its spineless cousin the Bishop's Cap, this one means business -- those spines are real.

Care Guide

How to grow the bishop's cap or monk's hood cactus

Light

Needs at least 6 hours

Water

water sparingly (water small amounts, less often.

Humidity

60-80%

Temperature

Prefers warm summers above 70°F

Soil

Sandy, fast-draining cactus mix with a pH of 5.

Propagation

Primarily seed-grown; sow fresh seeds

Common Problems

Root rot from overwatering is the main threat.

Did You Know

Fun Facts

Astrophytum ornatum is listed as Vulnerable on the IUCN Red List, threatened by habitat loss from livestock grazing, mining, land conversion, and illegal collection; it is also protected under Appendix II of CITES.

Pet Safety

Pet safe

Non-toxic to humans and pets. The spines are the main physical hazard -- handle with folded newspaper or thick gloves.

the bishop's cap or monk's hood cactus

How to grow the bishop's cap or monk's hood cactus

Fun Facts

Pet safe

Sources

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