Everything to know about Astrophytum Myriostigma (Bishop's Cap)

Updated: August 02, 2024

Everything to know about Astrophytum Myriostigma (Bishop's Cap)

If you are looking for an exciting and extraordinary spineless cactus, go for the Astrophytum Myriostigma plant. Native to Mexico, the Astrophytum myriostigma has several other common names, such as Bishop’s Cap Plant, Bishop’s Hat, Bishop's Miter, Monk's Hood, Deacons Hat, or Star Cactus.

This Bishop's cap cactus variety is loved by people for its easy-going nature. It makes a superb addition to your indoor as well as outdoor spaces. However, to flaunt it at your place, place it on windowsills, bookshelves, or desks.

If you wish to learn how to grow and care for Bishop's cap cactus, this blog is the best guide for you. It will take you through minute details for cultivating and caring for this charming star-like cacti.

Characteristics of Astrophytum Bishop's Cap Cactus

Buy Astrophytum myriostigma Here At Planet Desert

Bishop’s hat is an exclusive houseplant that comes from the highlands of northeastern and central Mexico and the flowering cactus family of Cactaceae.

It features a star-like appearance which has got its name “Astrophytum”, which means “star plant” in Greek.

Additionally, as it grows taller and older, its ribs are covered with hairy and white spots that look like the traditional headdress donned by bishops, due to which it is also famous as the bishop’s miter.

This species of Astrophytum myriostigma experiences slow growth but is relatively simple and easy to grow. It is known for its distinctive star-shaped pattern of white flecks on its green skin.

Being a tall species of cactus, it can grow up to 12 inches tall and 7 inches wide. They can have 3 to 7 bulky and vertical ribs. However, they usually have five non-spiky ribs.

In their habitat, their cylindrical to globular stems are covered with the noticeable white mob of trichomes. Some varieties may lack these spots.

The Bishop's cap cactus flowers may take up to 6 years to bloom but the wait is worth it! Its daisy-like flowers come in different colors having yellow, pink-violet, or creamy white base and a red, orange, or creamy yellow center.

How To Grow & Care for Astrophytum Myriostigma (Bishop's Cap)

Astrophytum myriostigma is a favorite among succulent enthusiasts for its distinctive look and low maintenance needs. Ideal for both indoor and outdoor cultivation, this plant adds an elegant touch to any plant collection with its minimalist yet striking beauty. This cactus species is easy to grow and care for. Here is a detailed guide for you so you can do proper Astrophytum myriostigma care and face no challenges while growing it.

Bishop's Cap: How Much Light Does it Really Needs? 

When growing indoors, Bishop's Cap thrives in bright, indirect sunlight. Put it near a south or west-facing window where it can receive plenty of natural light without being exposed to direct midday sun, which can scorch its delicate skin. If natural light is insufficient, supplement with a grow light to ensure the cactus gets adequate illumination for healthy growth.

Outdoors, the myriostigma cactus prefers a location with partial shade to full sun for a minimum of 6 hours every day.  In its natural habitat, it can tolerate direct sunlight, but in cultivated settings, it's best to provide some protection from intense afternoon sun, especially in hot climates. A spot with morning sun and afternoon shade is ideal to mimic its native environment and promote optimal growth.

Pro Tip

If you live in a place with cooler climates and where sunlight is not too harsh then only you can put it in full sunlight.

Bishop's Cap Cactus Optimal Soil and Fertilization Needs

The Astrophytum myriostigma will be happy if planted in well-drained, sandy soil. Planet Desert specializes in cacti and has specialized cactus potting soil that includes an organic substrate with mycorrhizae to help with the growth of a healthy root system to help your cactus thrive.

As an okay alternative, you can create your own potting mix by combining equal portions of perlite, coarse sand, and good natural potting soil.

When it comes to fertilization, the Bishop's Cap benefits from light fertilization once a year in the spring during its growing season. Use a balanced (5-10-5), water-soluble NPK fertilizer diluted to half strength.

Make sure you use a diluted liquid fertilizer with low nitrogen levels. Avoid over-fertilizing, as this can cause excessive growth and weaken the plant.

During the dormant winter period, refrain from fertilizing, allowing the cactus to rest and conserve its energy for the next growing season.

Understanding Bishop's Cap Watering Needs

Astrophytum myriostigma requires careful watering to thrive. This cactus, native to the arid regions of Mexico, is adapted to survive in dry conditions with minimal water. Overwatering can be detrimental, leading to root rot and other fungal diseases. Therefore, it is crucial to water this plant sparingly.

From the spring to early fall, during the growing season, water the Bishop's Cap deeply but infrequently. Allow the soil to dry out completely between watering sessions. This mimics the natural drought conditions of its native habitat and prevents the roots from sitting in water, which can cause damage. A good rule of thumb is to wait until the top inch of the soil is completely dry before watering again.

In the winter months, the Bishop's Cap enters a dormant period and requires even less water. During this time, significantly reduce the watering frequency, often to once a month or less. The soil should be allowed to remain mostly dry, as the plant's water requirements are minimal during dormancy. This period of reduced watering is essential for the cactus's health and helps to prepare it for the next growing season.

Ideal Temperature and Humidity Essentials for Bishop's Cap


For indoor cultivation, Astrophytum myriostigma thrives in warm temperatures. The optimal temperature range is between 70-85°F during the growing season. It's crucial to avoid exposing the cactus to temperatures below 50°F, as it is sensitive to cold.

During winter, when the plant is dormant, keeping it in a cooler room with temperatures around 60°F is beneficial. This slight temperature drop helps mimic its natural habitat and encourages healthy growth cycles.

When grown outdoors, Astrophytum myriostigma is suitable for USDA zones 9-11.In these zones, the cactus can be grown year-round without the need for special protection.

It can tolerate higher temperatures, often found in desert climates, but should be shielded from extreme heatwaves which can cause stress.

Providing some afternoon shade in the hottest months can help maintain its health. It's important to ensure that outdoor Bishop's Cap cacti are planted in well-draining soil to prevent root rot, especially during the rainy season.

Humidity levels for Bishop's Cap should be kept low, as it prefers arid conditions. High humidity can lead to fungal issues and rot, which are detrimental to the cactus. Indoors, maintain low humidity by ensuring good air circulation and avoiding placement in bathrooms or kitchens where moisture levels are higher. For outdoor plants, dry climates are ideal, and if you live in a more humid region, consider planting the cactus in a raised bed or container to improve drainage and reduce the risk of excess moisture.

Bishop's Cap Cactus Propagation

Use Astrophytum myriostigma seeds for quick and hassle-free propagation. Instead of purchasing its seeds from any nursery, it is best to collect them from its dried flowers. To let it germinate ideally, put the seeds in loamy and well-draining soil, and offer it light moisture, and indirect sun exposure. Once germination begins and little growth is noticeable, you can transplant that baby Bishop’s hat into a separate porous pot.

Potting & Repotting of Astrophytum myriostigma

When it comes to buying an ideal pot for this cactus, choose the ones designed from permeable material for excellent drainage. Ensure the best Astrophytum myriostigma care with a terracotta, clay, or ceramic pot.

Usually, your star cactus can stay happily in the same pot for around 4-5 years. So, repotting is a breeze. To repot, carefully remove the cactus from the pot and remove any loose soil from its roots along with any dead roots. You can either get a new pot or use the old one for repotting. However, you need a fresh potting soil mix for successful repotting. Compress the soil gently and water it.

Bishop's Cap Plant: Toxicity, Common Pests & Diseases

This charming Bishop's Cap Cactus is non-toxic to pets and human beings. Therefore, it can be planted in your home garden. However, it can be a point of attraction for few common pests and problems. They can easily hide under the hairy areolas, so keep an eye on them and treat them on time with a suitable insecticide. 

Mealybugs: White, cottony patches appear on the stem and leaves, and can be removed by isolating the plant, using a cotton swab or insecticidal soap, and repotting with fresh soil. Regular monitoring and pruning can also help prevent re-infestation.

Spider mites: Yellowing or bronzing of the plant, fine webbing, and tiny moving dots indicate an infestation, which can be controlled by spraying with insecticidal soap or neem oil, increasing humidity, and pruning infested areas. Isolating the plant and reducing watering can also help.

Scale insects: Small, armored bumps on the stem and leaves require removal with a cotton swab or insecticidal soap, followed by repotting with fresh soil. Regular monitoring and pruning can also help prevent re-infestation.

Root mealybugs: Symptoms include softening of the stem, discoloration, and poor growth, and treatment involves repotting with fresh soil, removing affected roots, and treating with insecticidal soap or systemic insecticides. Improving air circulation and reducing watering can also help prevent re-infestation.

Overwatering: Symptoms include softening of the stem, discoloration, and root rot, and treatment involves repotting with fresh soil, reducing watering, and improving air circulation. Allowing the plant to dry slightly between waterings can also help prevent root rot.

Underwatering: Symptoms include shriveling, wrinkling, or discoloration, and treatment involves increasing watering frequency, but avoiding overwatering, and ensuring good air circulation. Monitoring soil moisture and adjusting watering schedules can also help prevent underwatering.

Regular monitoring and appropriate pest control measures can help prevent and manage these issues. It will maintain the beauty of your star cactus! 

Where to Buy Astrophytum myriostigma?

When it comes to buying Bishop's Cap Astrophytum myriostigma, you might be able to find it at local nurseries or garden centers in your area that specialize in succulents and cacti. But Planet Desert is your easiest and best option if you're looking to buy affordable cacti online and have them conveniently shipped right to your door!

Here is the link to our product page for Astrophytum myriostigma. Here at Planet Desert, we have a large selection of over 500 cacti & succulents in stock and ready to ship nationwide. We guarantee that all our plants are of high quality and will arrive happy and healthy. 

Growers Reference Guide - Astrophytum myriostigma 

Bloom Season Summer
Botanical Name Astrophytum myriostigma
Common Name Bishop's Cap 
Dormancy Winter
Family Cactaceae
Flower Color Pale Yellow--Golden white
Genus Astrophytum
Growth Habit Globular
Growth Rate Slow
Hardiness Zone 9--10--11
Mature Size 12 in. tall--8 in. wide
Native Area Mexico
Plant Type Perennial cactus
Propagation By seeds
Resistance Drought tolerant--deer resistant--heat tolerant
Soil PH 6.5--Acidic--Neutral
Soil Type Cactus potting mix soil
Special Features Easy to maintain--Showy Blooms
Sun Exposure Full sun--partial shade
Toxicity Safe for humans--friendly to dogs--friendly to cats
Watering Needs Low

The Bottom Line

Overall, the Bishop's Cap cactus (Astrophytum myriostigma), is a captivating cactus species known for its unique shape and increasing number of ribs as it matures. This cactus is relatively easy to care for, making it a great choice for both experienced plant enthusiasts and beginners. It thrives in well-draining soil and requires bright, indirect light. Now that you have gone through the Bishop's Cap care guide, bring this attractive Astrophytum myriostigma home and add great vibes to your space.

Frequently Asked Questions

  • How do you take care of Astrophytum myriostigma? 

    Astrophytum myriostigma (Bishop's Cap cactus) is a low-maintenance cactus that thrives in bright, indirect light, so make sure to place it near a sunny window. When it comes to watering your Astrophytum myriostigma, allow the soil to dry out completely between waterings, and be cautious not to overwater. During the winter months, reduce watering even further. As for the temperature, this Bishop’s cap cactus prefers warm conditions, ideally between 50 and 55°F. Additionally, use well-draining soil and avoid excessive fertilization.

  • What is the minimum indoor temperature for Astrophytum myriostigma? 

    The minimum indoor temperature for Astrophytum myriostigma (Bishop's Cap cactus) should be around 50–55 °F. It's important to keep this cactus in a warm environment to ensure its optimal growth. If the temperature drops below this range, it might cause harm to the plant. So, make sure to keep it cozy and warm!

  • How do you propagate bishops cap? 

    Bishop's Cap cactus, or Astrophytum myriostigma, is primarily propagated from seeds. You can collect the seeds from mature fruits or purchase them from a reputable source. If you are in one of USDA zones 10 through 11, you can cultivate Astrophytum seeds outside. In colder climates, you can start indoor sowing on a seed mat or under a grow lamp. To propagate from seeds, sow them in well-draining soil and lightly cover them. Keep the soil slightly moist and provide bright, indirect light. With time and proper care, the seeds should germinate, and you'll have new Bishop's Cap cacti sprouting up.  

  • How big does Bishop's Cap Cactus get? 

    The Bishop’s Cap cactus (Astrophytum myriostigma) can grow to be about 8–40 inches tall and 4–8 inches wide. It has a unique shape, resembling a bishop's miter or hat, which gives it its name. As the cactus matures, it develops more pronounced ribs, which are vertical lines or ridges that run along its body. These ribs increase in number and become more prominent with age, adding to the cactus's distinctive appearance. It's a relatively small cactus compared to some others, but it can still make a beautiful addition to your plant collection.

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