Bishop’s Cap Cactus: Astrophytum Myriostigma Growing and Care

Bishop’s Cap cactus aka Astrophytum myriostigma (ass-tro-FY-tum MEE-ree-oh-STIG-mah) is a flowering spineless cactus species belonging to the Cactaceae family and genus Astrophytum.

It is interesting to note that the name – Astrophytum – originates from the Greek word ‘astron’ for star plant.

Bishop's cap Astrophytum cactus Bishop's hat
Flowers of Astrophytum Myriostigma Bishop Cap Cactus

The beautiful succulent Astrophytum Myriostigma like other plants from this genus grows in a shape similar to that of a star.

Bishop’s Cap Cactus Quick Care Guide

  • Botanical Name: Astrophytum myriostigma
  • Common Name(s): Bishop’s Cap cactus, Star cactus, Bishop’s Miter cactus, Bishop’s Hat
  • Family & Origin: Cactaceae, genus Astrophytum | Mexico
  • Growability: Easy
  • Grow Zone: USDA hardiness zones 10-11
  • Size: mature 23″-39″ inches tall, ” inches around
  • Flowering: Yellow with red or orange center, spring or early summer.
  • Light: Light shade never full sun
  • Temperature: 50°-68° degrees Fahrenheit
  • Water: Low water needs
  • Fertilizer:  Diluted liquid low nitrogen content fertilizer
  • Pests & Diseases: Mealybug, Plant Scale, Rot from overwatering
  • Propagation: Seeds
  • Grooming: None
  • Uses: Perfect house plant and window sill candidate

It is known as Echinocactus myriostigma and several common names:

  • Star Cactus
  • Bishop’s Miter cactus, Bishop’s Hood, Bishop’s Cap, Bishop’s Hat
  • Deacons Hat
  • Miter Cactus
  • Monk’s Hood

Bishop’s Cap is native to the highlands of northern and central Mexico, the plant grows in stony, calcareous soil.

Cactus Astrophytum was introduced into Europe in the mid 19th century.

In its natural habitat, the Bishop’s Hat grows at an elevation level of 2500′ – 5000 ‘ feet above the sea level and recommended for USDA hardiness zones 10-11.

Bishop’s Cap Cactus (Astrophytum) Care

Size & Growth

Young Bishop’s cap plants are more or less spherical in shape, having the form of a globe.

However, as the plant grows taller white hairy scales look more like a Bishop’s mitre, which is the traditional head-dress worn by bishops.

Generally, adult Bishop’s Cap plants are star-shaped, with 5 protruding ribs having white dots or spots.

However, keep in mind that the number of ribs can vary.

The star plant may have only 3 ribs or, in more rare cases, as many as 10 ribs!

The stem of a mature Astrophytum Myriostigma can grow up to 23″ – 39″ inches in height and around 8″ inches in diameter.

The growth rate of Bishop’s Cap is slow and the plant takes its time to grow and produce flowers.

Flowering and Fragrance

While the foliage is attractive on its own, the yellow flower only adds to the beauty of Astrophytum Myriostigma.

The daisy-like flower appears at the top of a mature plant and is usually no more than 2″ inches in diameter.

Each flower blooms for about 2 days. However, the flowers bloom in succession so the flowering season can last for months.

Yellow in color with a red or orange center, the flowers appear during spring or in early summer.

Despite the slow growth rate, even young plants can bloom easily. These flowers have a faint trailing scent.

Light & Temperature

Astrophytum myriostigma enjoys light and warmth.

However, young plants cannot handle strong sunlight. Plants do best in light shade and should never be placed in full sun.

Keep in mind that these plants require winter rest.

As the temperature drops during the end of the year, maintain the temperature below 50° degrees Fahrenheit to allow the plant to rest during winter.

Watering and Feeding

Astrophytum plants do not require lots of water. During colder weather, from October till March, refrain from watering them at all.

Begin watering sparingly during March. Slowly, increase watering as temperatures rise.

Keep in mind that while Astrophytum Myriostigma requires water in small amounts during the summer, it is important to make sure the plant is not overwatered.

Just like water, these plants do not need to be fed a lot.

Use a diluted liquid low nitrogen content fertilizer once a month during summer and stop as winter sets in.

If you click this link and make a purchase, we earn a commission at no additional cost to you.

Soil & Transplanting

Native to rocky terrain, Astrophytum Myriostigma grows best in a cactus soil or a mixture of 25% coarse sand, 25% pumice, and 50% potting soil.

In order to protect the neck of the plant, spread a layer of sand over the surface of the soil in the pot.

Because of the small root zone plant Astrophytum Myriostigma in small pots. If repotting is required, it is best to wait till early spring before transplanting these plants.

Grooming and Maintenance

Bishop’s Cap plants might be small (perfect for a window sill), and when it comes to grooming and maintenance, they are quite self-sufficient.

There’s not much to do except for admiring the plant. For this reason, Astrophytum species are one of the easiest to grow and care for.

Start shaped Astrophytum cactus
Potted Astrophytum Myriostigma Bishop Cap Cactus starting to bloom

How to Propagate Astrophytum Myriostigma

The best way to propagate Astrophytum plants is from seeds.

Use sandy and well-drained propagating soil.

Lightly press the seeds in the soil. Maintain the temperature of the soil at around 78° degrees Fahrenheit, keeping it lightly moist.

As the Bishop’s Cap seeds germinate and grow, move them to individual pots.

The ideal soil to use for young plants is a mixture of:

  • 25% coarse sand
  • 25% pumice
  • 50% potting soil

Also, don’t forget to sprinkle a thin layer of sand over the surface of the soil!

Keep in mind that while it is advisable to provide young plants with as much light as possible.

Keep them out of direct sunlight and excessively high temperatures as they are still too delicate to withstand these conditions.

Astrophytum Bishops Cap Pest or Disease Problems

These plants are resistant to most houseplant pests as long as they are kept cool during the winter.

If kept in higher temperatures during the colder months, the plant is susceptible to attacks by mealybugs and scale insects.

When attacks happen, remove the insects with the help of a toothpick and treat the affected areas with a piece of cotton dipped in alcohol.

It is also common to notice brown patches around the base of older plants.

However, if similar spots appear in younger plants, it is indicative that the soil is staying too wet.

The best approach is to stop watering the plant. When needed, place the pot in a tray full of water.

Allow the plant will take up all the water it requires in about 30 minutes.

Also, spread a thin layer of sand over the soil as it helps keep the plant’s neck dry.

Botanical Drawing - Echinocactus myriostigma - Astrophytum Bishop's Cap
Botanical Illistration – Echinocactus myriostigma – Astrophytum
From the book – Lemaire, Charles Antoine – Iconographie descriptive des cactées.

Uses For Bishop’s Cap Astrophytum Cactus

The small size and slow growth of Astrophytum Myriostigma make it an excellent house plant.

The cherry on top – the beautiful yellow flowers offer a perfect alternative to add a little color to any household.

As the Bishop’s Cap enjoys light and warmth, it is ideal for placing it near windows or on windowsills.

It is one of the easiest to succulent cactus to look after and generally recommended to beginner gardeners.

Recommended Reading

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.