Bishop's Cap Cactus

Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ Care & Buying Guide


Light requirements Medium
Water requirements Low
Ease of care Easy
Size Large
Toxicity Non-toxic
Zone 9a to 11b
Temperature resistance A little frost-hardy
Growth speed Slow
Indoor growing Suitable


Taking Care Of Astrophytum Myriostigma ‘Bishop’s Cap Cactus’

Ideal conditions

Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ prefers shade to full sunlight, though it can benefit from direct sunlight on moderately warm days. Thanks to its not too high sunlight demands, the Bishop’s Cap Cactus can be grown either indoors or outdoors.

In terms of cold resistance, the Bishop’s Cap Cactus tolerates low temperatures better than many other cacti. It can survive in temperatures as low as 20 degrees Fahrenheit (-6.7 degrees Celsius), though it shouldn’t be exposed to such temperatures for too long.


Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ only needs to be watered when its soil is dry to the touch. Do not overwater this cactus since if water accumulates in the soil, the roots of the plant may start to rot.

In winter, the Bishop’s Cap Cactus should be kept dry. Dormant in winter, this cactus requires very little water, and excessive amounts of water are much more likely to cause root rot in winter.

Where to plant

Plant the Bishop’s Cap Cactus in porous, quick-draining soil. For better draining, you may also add some pumice, coarse sand, or perlite to the mix. A mixture of 50% soil, 25% pumice, and 25% coarse sand appears to be optimal for this cactus.

Even if keeping the Bishop’s Cap Cactus outside, you should plant it in a pot to ensure that it can be easily moved around. Choose a pot with large drainage holes at the bottom.

Whether indoors or outdoors, Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ prefers partial shade and shouldn’t be exposed to full sunlight for too long, especially on hot days.

In winter, be sure to move Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ inside to protect it from cold. Though this cactus can tolerate moderate cold, it likes warm temperatures and shouldn’t be exposed to winter cold for long.

General care information

The Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ is quite a slow grower, and occasional fertilizing may allow you to ensure more consistent and perhaps quicker growth. Fertilize your Astrophytum Myriostigma ‘Bishop’s Cap Cactus’ once a month during summer with a low-nitrogen fertilizer diluted to half strength.

Though the Bishop’s Cap Cactus grows slowly, it gets quite big (up to 30 inches tall and 8 inches in diameter), and you’ll need to repot it a few times throughout its life. You may do so every spring or summer or only when you feel that the cactus has outgrown its current pot.

Yearly repotting is preferable since it allows you to inspect the cactus’ roots and remove any rotten or otherwise damaged parts. Besides, it allows you to introduce the plant to fresh, nutritious soil.

Before repotting, allow the soil of the cactus to dry. And after repotting, don’t water the cactus for about a week to allow it to recover.